1. bookVolume 56 (2022): Issue 1 (March 2022)
Journal Details
License
Format
Journal
eISSN
1581-3207
First Published
30 Apr 2007
Publication timeframe
4 times per year
Languages
English
access type Open Access

In vitro maturation of immature oocytes for fertility preservation in cancer patients compared to control patients with fertility problems in an in vitro fertilization program

Published Online: 22 Dec 2021
Page range: 119 - 128
Received: 05 Aug 2021
Accepted: 25 Nov 2021
Journal Details
License
Format
Journal
eISSN
1581-3207
First Published
30 Apr 2007
Publication timeframe
4 times per year
Languages
English
Abstract Background

The aim of this study was to determine whether in vitro maturation (IVM) of immature oocytes after controlled hormonal stimulation of the ovaries could be important in cancer patients to improve their chances of conception in the future.

Patients and methods

After ovarian stimulation in cancer patients, the number of oocytes and their quality and maturity were compared to control patients with fertility problems in the in vitro fertilization (IVF) program. In both groups of patients, immature oocytes at the developmental stage of germinal vesicle were matured in vitro and the proportion of oocytes that matured in vitro was compared between groups. In a subset of women with fertility problems, intracytoplasmic sperm injection (ICSI) was performed on IVM oocytes to assess their ability to be fertilized and develop into an embryo compared to vivo matured oocytes in the same cycles and consider the procedure in cancer patients.

Results

In patients with different cancers, the disease did not affect the number and quality of retrieved oocytes. In cancer patients, there was even a significantly lower proportion of immature oocytes than in patients with fertility problems (30.0% vs. 43.6%; P < 0.05). However, in patients with cancer, fewer oocytes per patient matured in vitro than in patients with fertility problems (1.39 ± 1.04 vs. 2.48 ± 1.83; P < 0.05). After ICSI, the proportions of fertilized oocytes and fertilized oocytes developing into an embryo did not differ between oocytes matured in vitro and in vivo in the same cycles.

Conclusions

Oocyte IVM is proving to be a reliable procedure for resolving immature oocytes after controlled ovarian stimulation in cancer patients.

Key words

Introduction

Many young women in the reproductive period of life who do not yet have children or would like to have another child suffer from cancer. Today, cancer therapies are successful, but unfortunately, they can negatively affect the ovarian function (including oocyte quality) and fertility. At a median of 5.0 years from initial breast cancer diagnosis, 49% patients after adjuvant chemotherapy with anthracyclines and taxanes and 11% after therapy with tamoxifen had become post- and peri-menopausal.1 Decreased ovarian follicle reserve occurs in more than one-third of patients after breast cancer treatment resulting in permanent infertility.2 In long-term female survivors of pediatric hema tologic malignancies 26.7% experienced premature ovarian insufficiency and face infertility after cancer treatment.3 The situation is similar with other cancers; cancer therapy is the cause of premature ovarian failure in 25% of women with this diagnosis.4 Therefore, it is very important to consider the preservation of female fertility before oncotherapy. An improvement in the survival rates of cancer patients and recent advances in assisted reproductive technologies have led to significant progress in fertility preservation treatments.

One option is vitrification and long-term storage of the patient's oocytes for later in vitro fertilization (IVF) with partner's sperm and transfer of embryos into the uterus. This program is established in many health care institutions around the world for a variety of cancers, including breast cancer.5, 6, 7, 8, 9, 10, 11, 12 Oocyte cryopreservation is an effective approach5, 6, 7, 8, 9, 10, 11, 12, but it is still thought that further studies are needed in cancer patients to ensure the excellent outcomes obtained in women without cancer.16 After controlled hormonal stimulation of the ovaries, in vitro maturation (IVM) of immature oocytes before vitrification is recommended and not after vitrification/ devitrification procedure.17 Even if there are no differences in survival rates between oocytes vitrified before or after IVM procedure, decreased maturation rates of immature oocytes vitrified before IVM may be explained by underlying ultrastructural and biomolecular alterations.17

Human oocyte cryopreservation may offer some advantages compared to embryo freezing in cancer patients and also eliminates some ethical, legal, and moral concerns of embryo freezing17, and is an option in young cancer patients who are single.9,18 However, the chance of success depends primarily on the number of oocytes that have been vitrified in the patient15 and some breast cancer patients may have contraindications to exogenous gonadotropin administration for controlled ovarian stimulation.19 Some recent data show that ovarian stimulation for oocyte vitrification does not modify disease-free survival and overall survival rates in patients with early breast cancer20 and the safety of pregnancy after an established diagnosis of breast cancer has been confirmed in numerous studies.21

In the case of vitrification and storage of oocytes, controlled hormonal stimulation of the ovaries is required to obtain oocytes. Despite careful hormonal stimulation of the ovaries, the significant proportion of oocytes obtained by ultrasound-guided aspiration of ovarian follicles is immature as metaphase I (MI) oocytes or prophase I oocytes with germinal vesicle (GV). Immature MI oocytes mostly mature spontaneously in vitro and are vitrified, while immature GV oocytes do not mature spontaneously and are incapable of fertilization. Therefore, GV oocytes are not vitrified and stored in liquid nitrogen in clinical practice and are discarded and lost to the patient. The important question is whether the maturation of these oocytes in vitro makes sense. There is a lack of data regarding the outcome of in vitro matured oocytes cryopreserved in cancer patients.22 Recently, the first birth achieved after fertility preservation using vitrification of in vitro matured oocytes in a patient with breast cancer has been reported.23

The purpose of this study was to investigate the effectiveness of maturation of immature GV oocytes of cancer patients in laboratory conditions (in maturation medium and co-culture with cumulus cells from mature oocytes of the same patients) compared to control women involved in the IVF program due to fertility problems. Because all oocytes of cancer patients are still frozen, we tried to elucidate the success of IVF procedure, actually intracytoplasmic sperm injection (ICSI), on the in vitro matured oocytes of patients with fertility problems as a model for cancer patients.

Patients and methods

This research was approved by the Slovenian National Medical Ethical Committee (No. 0120222/2016-2; KME 115/04/16). In this prospective research the immature (germinal vesicle-GV, prophase I) oocytes of two groups of patients were included: i) 45 oocytes of 18 cancer patients with predominating breast cancer (Figure 1) and ii) 74 oocytes of 21 healthy (non-cancer) patients (control) with fertility problems (partners of infertile men with impaired semen quality: oligozoospermia with less than 15 million spermatozoa/ml or teratozoospermia with less than 4% morphologically normal spermatozoa according to the World Health Organization (WHO) Criteria 201024 who were included in the IVF program. All patients were in the reproductive period of life, aged 18 to 43 years.

Figure 1

Types of disease in cancer patients included in this study. Breast cancer patients predominated.

Oocytes after controlled hormonal stimulation of the ovaries

In both groups of patients, both immature and mature oocytes were together retrieved after controlled hormonal stimulation of the ovaries using the same, antagonist protocol and ultrasoundguided aspiration of ovarian follicles. In patients with fertility problems, the stimulation was started on day 2 of the menstrual cycle with 150 to 300 I.U. of recombinant follicle-stimulating hormone (rFSH) daily. In cancer patients, the stimulation was initiated immediately after they have been sent to our department, no matter of the cycle phase. The ovarian stimulation was started with 225 to 300 I.U. of rFSH. In breast cancer patients, an aromatase inhibitor – letrozole (2.5 mg every 12 hours) was added to prevent estradiol rise and its possible detrimental effect on breast cancer. In all patients, the gonadotropin-releasing hormone (GnRH) antagonist was added, when dominant follicle measured 14 mm in a diameter. In patients with fertility problems, the oocyte maturation was triggered with choriogonadotropin alfa – Ovitrelle, when follicles measured 18 mm or more. If there were more than 15 follicles in both ovaries, the maturation triggering was performed with GnRH agonist. In majority of cancer patients, GnRH agonist was used for oocyte maturation to prevent ovarian hyperstimulation (ovarian hyperstimulation syndrome; OHSS), but some of them, if there were less than 10 follicles in both ovaries, were also treated by Ovitrelle. All follicles with a diameter of 16 mm or more were aspirated in all patients. A constant aspiration pressure of 180 mm Hg was used to aspirate the oocytes from the follicles.

Mature oocytes with expressed polar body were immediately vitrified by soaking in a mixture of cryoprotectants, direct plunging into liquid nitrogen (-196oC), and stored in it, as described elsewhere.25

In vitro maturation of immature oocytes

Immature GV oocytes were exposed to the procedure of IVM in a seria of media of the IVM Maturation System (MediCult IVM®System, Origio/CooperSurgical, Denmark).

For IVM, each GV oocyte was first exposed for two hours in the LAG Medium for conditioning and then for 24 to 28 hours to the maturation medium of this system containing the reproductive hormones: follicle stimulating hormone (FSH; 75 mIU/ ml) and human chorionic gonadotropin (HCG; 100 mIU/ml) and in a co-culture with cumulus cells denuded from mature oocytes of the same patient, as described elsewhere (Figure 2).26 During incubation in these media, oocytes were cultured in a CO2incubator at 37oC and 6% CO2 in air. Oocytes were supposed to be mature (in a metaphase II) when they extruded a polar body. All oocytes of cancer patients and the majority of oocytes of women with fertility problems that matured in vitro were vitrified and stored in liquid nitrogen for later clinical use (IVF). Patients with ≥ 31% GV oocytes had increased oocyte immaturity. A subset of in vitro matured oocytes of women with fertility problems was fertilized in vitro.

Figure 2

In vitro maturation of the oocyte in the maturation medium and in coculture with the cumulus cells of mature oocytes in the same patient at magnification 40 X (A) and magnification 100 X (B).

CC = cumulus (granulosa) cells; O = oocyte; Red bar = A) 100 μm in B) 50 μm

In vitro fertilization by ICSI

In a subgroup of 17 in vitro matured oocytes from 17 patients (1 oocyte per patient) with fertility problems (female partners of infertile men with oligozoospermia or teratozospermia) ICSI was performed with partner's sperm one day later after oocyte and sperm retrieval from a couple. Oocytes were denuded by hyaluronidase to remove the cumulus cells and microinjection of one spermatozoon per oocyte was performed, as described elsewhere.27 Only motile spermatozoa were used for ICSI. The next day, fertilization (presence of two pronuclei and extruded second polar body) was checked and embryo cleavage one day later. Good quality embryos were vitrified and stored in liquid nitrogen (-196oC) for later clinical use (transfer to the uterus). The rates of fertilization and embryo cleavage were compared between oocytes that matured in vitro and in vivo (in the ovaries; aspirated as mature) in the same patients after controlled ovarian hormonal stimulation.

Statistics

Both groups of patients, cancer and infertile patients, were compared in terms of the number of oocytes obtained after controlled hormonal stimulation of their ovaries, the proportion of immature and degenerated oocytes, and the proportion of immature (GV) oocytes that matured in vitro. Due to the relatively small number of patients/oocytes included and the abnormal distribution of data, tested by Shapiro-Wilk normality test, non-parametric tests (Fisher's exact and Mann-Whitney U tests) were performed; statistical significance was set at P < 0.05. After ICSI, the fertilization and embryo cleavage rates of oocytes that matured in vitro were compared with oocytes of the same patients that matured in vivo and were aspirated from the ovaries as mature oocytes in the same cycle of controlled ovarian hormonal stimulation using Fisher's exact and Wilcoxon tests; statistical significance was set at P < 0.05.

Results

Cancer patients had different types of cancer, but breast cancer was predominant (Figure 1). The average age of cancer patients was 30.3 ± 6.3 years and of women with fertility problems 33.4 ± 5.0 years. The two groups of women did not differ significantly in their age. There was also no significant difference in the age of patients with breast cancer and patients with other cancers (32.0 ± 6.2 vs. 29.0 ± 6.0 years).

Numbers, quality and immaturity of oocytes after controlled hormonal stimulation of the ovaries

After controlled hormonal stimulation of the ovaries, 198 oocytes were retrieved in cancer patients and 259 oocytes in infertile women. Cancer patients and patients with fertility problems did not differ significantly in the number of retrieved oocytes (11.0 ± 9.0 oocytes/patient vs. 12.3 ± 9.2 oocytes/patient), as revealed by Mann-Whitney U test. In cancer patients, the proportion of immature GV and MI oocytes was significantly lower than in patients with fertility problems (30.0% vs. 43.6%; P < 0.05), as revealed by Fisher's exact test (Table 1). The groups did not differ significantly in the proportion of GV oocytes (23.0% vs. 28.6%) (Table 1); among patients with immature oocytes, 50% of cancer patients and 48.0% of patients with fertility problems had increased proportion (≥ 31%) of GV oocytes with a germinal vesicle, which did not differ significantly. There was also no difference in the proportion of degenerated oocytes between cancer patients and patients with fertility problems (8.6 vs. 6.5%) (Table 1).

Differences in the number, quality and immaturity of oocytes after controlled hormonal stimulation of the ovaries in cancer patients compared to patients with fertility problems

Cancer patients (n = 18) Patients with fertility problems (n = 21)
Age (years) 30.3 ± 6.3 33.4 ± 5.0
Number of retrieved oocytes 198 259
Oocytes per patient 11.0 ± 9.0 12.3 ± 9.2
Number of degenerated oocytes 17 (8.6%) 17 (6.5%)
Number of immature (MI + GV) oocytes 59 (30.0%)* 113 (43.6%) *
Number of immature GV oocytes 45 (23.0%) 74 (28.6%)

* = statistically significant difference (P = 0.0064) revealed by Fisher's exact test; significance was set at P < 0.05; GV = germinal vesicle; MI = metaphase I (oocyte meiosis)

If we considered the type of cancer, we found that there was no significant difference in the number of all immature (MI and GV) oocytes in patients with breast cancer compared to patients with fertility problems or patients with other cancers (4.17 ± 3.25 vs. 5.29 ± 3.76 and 2.92 ± 2.47 immature oocytes/patient, respectively), as revealed by Mann-Whitney U test. There was also no statistically significant difference in the proportion of all immature (GV and MI) oocytes in breast cancer patients compared to patients with other cancers or patients with fertility problems (36.0% vs. 27.0% and 43.6%), as found using the Fisher's exact test. Nevertheless, there was a tendency for a significantly higher proportion of immature, GV oocytes in breast cancer patients compared to patients with other cancers (31.43% vs. 18.75%; P = 0.0531, Fisher's exact test).

In vitro matured oocytes

Forty-five GV oocytes in cancer patients and 74 GV oocytes in patients with fertility problems underwent IVM procedure (Table 2); the proportion of oocytes (15.5% in cancer patients and 12.2% in women with fertility problems) degenerated just before or during conditioning in LAG medium. We found that a lower proportion of oocytes matured in vitro in cancer patients compared to patients with fertility problems (66.0 vs. 80.0%), however, the difference was not statistically significant, as revealed by Fisher's exact test. In spite of that, number of oocytes that matured in vitro per patient was significantly lower in cancer patients than in patients with fertility problems (1.39 ± 1.04 vs. 2.48 ± 1.83 oocytes/patient; P < 0.05, Mann-Whitney U test), as shown in Table 2.

Numbers and percentages of oocytes that matured in vitro in patients with different cancers compared to patients with fertility problems

Number of oocytes that underwent in vitro maturation Number of oocytes that matured in vitro
All cancer patients (n = 18) 38 / 45 25 (1.39 ± 1.04 per patient)* (66.0%)
Patients with breast cancer (n = 8) 22 12 (54.5%)
Patients with other cancers (n = 10) 16 13 (81.2%)
Patients with fertility problems (n = 21) 65 / 74 52 (2.48 ± 1.83 per patient)* (80.0%)

* = statistically significant difference (P < 0.05; Mann-Whitney U test)

In cancer patients, there was also a lower proportion of oocytes that matured in vitro in patients with breast cancer than in patients with other cancers and patients with fertility problems (54.5% vs. 81.2% and 80.0%) (Table 2). The difference between patients with breast cancer and women with fertility problems tended to be statistically significant (P = 0.0862; Fisher's exact test) and was probably not significant due to the relatively low number of oocytes included.

Overall, 198 oocytes were retrieved in cancer patients, of which 139 were mature. Following IVM, the number of total mature oocytes increased to 164 (13.0% increase in mature oocyte yield). In patients with fertility problems, 259 oocytes were retrieved, of which 146 were mature. After IVM, the number of total mature oocytes increased to 198, which means 20.1% increase in mature oocyte yield. Thus, there was no significant difference in the yield of mature oocytes after IVM between cancer patients and patients with fertility problems. 15.5% (7/45) GV oocytes in cancer patients and 12.2% (9/74) GV oocytes in patients with fertility problems degenerated before in vitro maturation procedure.

Results of ICSI of in vitro matured oocytes in patients with fertility problems

In vitro fertilization of 49 oocytes in 17 patients with fertility problems (average age 34.3 ± 4.4 years) was performed by ICSI with partner's semen (in 2 men oligozoospermia and 15 men teratozoospermia). After performing this method, 27 (55.1%) oocytes were fertilized (expressing two pronuclei and two polar bodies) and 23 (85.2%) fertilized oocytes (zygotes) further developed into an embryo, as shown in Table 3; four zygotes did not cleave further. Good quality embryos were vitrified and stored in liquid nitrogen for future clinical use in patients (transfer into the uterus).

Non-significant differences in fertilized oocytes, non-cleaved zygotes, and cleavage embryos obtained by intracytoplasmic sperm injection (ICSI) on in vitro matured and in vivo matured oocytes of patients with fertility problems (in the same cycles)

ICSI cycles (n = 17) In vitro matured oocytes In vivo matured oocytes*
Number of microinjected oocytes 49 121
Fertilized oocytes (55.127 %) (57.069 %)
Non-cleaved zygotes (15.04 %) (11.68 %)
Cleavage embryos (85.223 %) (88.461 %)

* = non-significant differences, as revealed by Fisher's exact test

After ICSI, the fertilization and cleavage rates of 49 oocytes that matured in vitro were compared with 121 oocytes of the same patients that matured in vivo and were aspirated from their ovaries as mature oocytes (metaphase II [MII] oocyte meiosis) in the same cycle of controlled ovarian hormonal stimulation. Of the 121 oocytes obtained as mature oocytes, 69 oocytes were fertilized, representing a fertilization rate of 57.0%. Sixty-one fertilized oocytes further developed into an embryo (Table 3). Fisher's exact test revealed no statistical differences in the proportions of fertilized oocytes, non-cleaved zygotes, and embryos obtained by ICSI on in vitro and in vivo matured oocytes (Table 3).

In patients with an increased proportion of immature (GV) oocytes (≥ 31%), there was a tendency for a lower proportion of fertilized oocytes and a higher proportion of non-cleaved zygotes, but the differences were not statistically significant (Table 4).

Non-significant differences in results of intracytoplasmic sperm injection (ICSI) cycles (fertilized oocytes, non-cleaved zygotes, cleavage embryos) on in vitro matured oocytes of patients with fertility problems regarding the number of immature (germinal vesicle [GV]) oocytes

ICSI cycles (n = 17) ≤ 30% GV oocytes ≥ 31% GV oocytes
Female age (years) 34.4 ± 3.0 34.3 ± 5.6
Number of microinjected oocytes 16 33
Fertilized oocytes 11 (69.0%) 16 (48.5%)
Non-cleaved zygotes 0 (0%) 4 (25.0%)
Cleavage embryos 11 (100%) 12 (75%)

Non-significant differences, as revealed by Fisher's exact test

Discussion

The results of this research show that cancer and control healthy patients with fertility problems did not differ in the number and quality of oocytes after controlled hormonal stimulation of their ovaries, which is positive. In cancer patients, there was even a significantly lower proportion of immature oocytes than in patients with fertility problems.

However, in patients with cancer, fewer oocytes per patient matured in vitro than in patients with fertility problems (1.39 ± 1.04 vs. 2.48 ± 1.83, P < 0.05). Following ICSI of oocytes in patients with fertility problems, the fertilization and embryo cleavage rates were approximately the same in oocytes that matured in vitro and in vivo in the same patients, in the same cycles of controlled hormonal stimulation of the ovaries. This is also to be expected in cancer patients.

The proportion of mature, MII oocytes in the patients with fertility problems included in this research was relatively low (56.4%) compared to the internationally accepted reference value of 7080%28, because we included mainly patients with a higher proportion of immature oocytes which did not reflect the average condition; in cancer patients, the proportion of mature oocytes was higher (70%) and within the reference value.28 The number and quality of oocytes in cancer patients did not differ between different cancers and from control patients with fertility problems. The same has been found in other studies for different types of cancer such as breast cancer, lymphoma, gliomas and other cancers.29,30 For breast cancer, the results of various studies are otherwise contradictory. In a study by Malacarne et al., as in our study, the average number of oocytes obtained per breast cancer patient after ovarian stimulation did not differ significantly from healthy control women including oocyte donors, women with fertility preservation for non-medical reasons, and female partners of infertile men in an IVF program31; it was concluded that patients with breast cancer undergoing controlled ovarian hormonal stimulation for fertility preservation can expect the ovarian response predicted for their age. The results obtained by different studies do not support the notion of a negative impact of the breast cancer gene 1/2 (BRCA1/2) mutation on the ovarian response of women with breast cancer.31, 32, 33 Nevertheless, the results of some other studies suggest the reduced number and maturity of oocytes obtained for cryostorage in patients with breast cancer34,which may be attributed to the higher grade of cancer35 or different expression of hormonal receptors.36

There is little data in the literature on how different cancers affect the oocyte IVM in cancer patients. The oocyte IVM rate in breast cancer patients was found to be approximately 53.2 to 64.2% in the study of Shalom Paz et al.37, which is very similar to our study (54.5%), or slightly higher – 62.0%, 66.0% or 66.7% in some other studies.22,32 In this study, the proportion of immature oocytes matured in vitro tended to be lower in breast cancer patients (54.5%) than in patients with fertility problems (80.0%), while this was not observed in patients with other cancers (81.2%). Although, the difference was not significant, possibly due to relatively low number of patients and oocytes included. In a study conducted by Liu et al., 811 genes were identified that were expressed differently in malignant breast tissue compared to healthy breast tissue38; among the up-regulated genes was also a group of genes involved in the cell cycle and progesteronemediated oocyte maturation. For cancer patients, Cohen et al. found that the mean oocyte maturation rate in stimulated IVF cycles was 38%39, which is significantly lower than in our study (66.0%; 54.5% in breast cancer and 81.0% in other cancers). In our study, IVM of oocytes in coculture with cumulus cells from mature oocytes in the same patients may have been beneficial, at least in part providing an ovarian niche.26 Also Chatroudi et al. found that cumulus cell supplementation in IVM culture media enhances the viability of human embryos (blastocysts) after IVF.40 The rates of in vitro matured oocytes in cancer patients and patients with fertility problems in our study were very similar to the published rates of IVM of immature oocytes in the usual IVF program, where 65.0%, 68.7%, 68.9% and 69.7% maturation rates were obtained in different maturation media.41, 42, 43 Oktay et al. reported the 45% increase in mature oocyte yield after IVM of immature oocytes after controlled hormonal stimulation of the ovaries in breast cancer patients and a high fertilization rate of these oocytes.44 Moreover, an IVM of oocytes retrieved without hormonal stimulation of the ovaries was considered for fertility preservation in breast cancer patients to avoid the ovarian stimulation, shorten the time to oocyte retrieval, and not to increase both the serum estradiol level and delay in cancer treatment.45, 46, 47

It should be noted that our study was limited to a relatively small number of patients involved and a small number of oocytes. In cancer patients and patients with fertility problems, we tried to perform as comparable controlled hormonal stimulation of the ovaries as possible using a GnRH antagonist. Nevertheless, we also had to take certain safety precautions in cancer patients. In these patients, the ovarian hormonal stimulation was initiated immediately after they have been sent to our department, no matter of the cycle phase to be fast and prevent further progression of disease. The oocyte maturation in cancer patients was initiated by GnRH analogue to prevent hyperstimulation, but more patients with less than 10 follicles were also treated with Ovitrelle similar to patients with fertility problems. Thus, in most patients, oocyte maturation was triggered by Ovitrelle. If we used exactly the same method of hormonal ovarian stimulation and triggering oocyte maturation in cancer patients and patients with fertility problems, there might be more immature oocytes in cancer patients, but this was not possible for cancer-related safety reasons.

In addition, for safety reasons, breast cancer patients were also treated with an aromatase inhibitor, letrozole, to prevent an increase in estradiol and worsening of the disease. Thus, based on our own experience and literature48,49, we believe that both random start of hormonal stimulation in cancer patients and use of aromatase inhibitor in patients with breast cancer do not affect the number, maturity and in vitro maturation of oocytes obtained in these patients.

Letrozole treatment may also increase the intraovarian androgen levels, which have a negative impact on granulosa cells (apoptosis) in the late antral and pre-ovulatory follicles.50 In this research, granulosa (cumulus) cells were used in co-culture for oocyte maturation, which may lower the maturation rate. However, we performed in vitro maturation of oocytes with cumulus cells of mature oocytes because our previous work showed that coculture with cumulus cells does not affect the proportion of in vitro matured oocytes, but improves the molecular status of oocytes (gene expression profile) compared to oocytes matured in vivo.26

In patients with fertility problems, we determined the FSH, LH and AMH levels in early follicular phase of the cycle as well as the number of antral follicles. For cancer patients, we have no such data. Only informative ovarian scan with antral follicle estimation was performed at the beginning of ovarian stimulation.

In our study, approximately the same proportion of oocytes were fertilized and further cleaved into an embryo after ICSI of in vitro and in vivo matured oocytes. Some studies have shown poorer embryo development and live birth rates with in vitro matured oocytes51,52, which could be linked to structural and morphologic differences in human oocytes after IVM53 due to suboptimal maturation medium and lack of ovarian niche. It needs to be point out that in our study, oocyte IVM was performed in coculture with cumulus cells from mature oocytes of the same patients thus providing a degree of ovarian niche. In spite of a lower rate of good-quality embryos and different developmental dynamics of embryos, pregnancy rates as well as live births did not necessarily differ after oocyte IVM, as found by Roesner et al.54 Moreover, in a matched setting between IVM and IVF babies born from women with polycystic ovaries, no significant increased risk associated with IVM has been identified in 2-year-old singletons born after IVM and after a mean follow-up up to 7.5 years.55,56 In general, more studies are urgently required to improve IVM –vitrification method to successfully preserve oocytes collected from cancer patients.57,58

Conclusions

We may conclude that ‘rescue’ of immature oocytes with IVM is a useful strategy to improve the mature oocyte yield of fertility preservation cycles in cancer patients. Immature oocytes retrieved during oocyte and also embryo cryopreservation cycles in cancer patients should not be discarded in order to improve the future potential of pregnancy in these patients. Their immature oocytes can mature in vitro comparable to healthy controls. After ICSI, approximately the same proportion of in vitro matured oocytes could be fertilized and developed into an embryo as in oocytes matured in vivo.

Figure 1

Types of disease in cancer patients included in this study. Breast cancer patients predominated.
Types of disease in cancer patients included in this study. Breast cancer patients predominated.

Figure 2

In vitro maturation of the oocyte in the maturation medium and in coculture with the cumulus cells of mature oocytes in the same patient at magnification 40 X (A) and magnification 100 X (B).
CC = cumulus (granulosa) cells; O = oocyte; Red bar = A) 100 μm in B) 50 μm
In vitro maturation of the oocyte in the maturation medium and in coculture with the cumulus cells of mature oocytes in the same patient at magnification 40 X (A) and magnification 100 X (B). CC = cumulus (granulosa) cells; O = oocyte; Red bar = A) 100 μm in B) 50 μm

Non-significant differences in fertilized oocytes, non-cleaved zygotes, and cleavage embryos obtained by intracytoplasmic sperm injection (ICSI) on in vitro matured and in vivo matured oocytes of patients with fertility problems (in the same cycles)

ICSI cycles (n = 17) In vitro matured oocytes In vivo matured oocytes*
Number of microinjected oocytes 49 121
Fertilized oocytes (55.127 %) (57.069 %)
Non-cleaved zygotes (15.04 %) (11.68 %)
Cleavage embryos (85.223 %) (88.461 %)

Numbers and percentages of oocytes that matured in vitro in patients with different cancers compared to patients with fertility problems

Number of oocytes that underwent in vitro maturation Number of oocytes that matured in vitro
All cancer patients (n = 18) 38 / 45 25 (1.39 ± 1.04 per patient)* (66.0%)
Patients with breast cancer (n = 8) 22 12 (54.5%)
Patients with other cancers (n = 10) 16 13 (81.2%)
Patients with fertility problems (n = 21) 65 / 74 52 (2.48 ± 1.83 per patient)* (80.0%)

Differences in the number, quality and immaturity of oocytes after controlled hormonal stimulation of the ovaries in cancer patients compared to patients with fertility problems

Cancer patients (n = 18) Patients with fertility problems (n = 21)
Age (years) 30.3 ± 6.3 33.4 ± 5.0
Number of retrieved oocytes 198 259
Oocytes per patient 11.0 ± 9.0 12.3 ± 9.2
Number of degenerated oocytes 17 (8.6%) 17 (6.5%)
Number of immature (MI + GV) oocytes 59 (30.0%)* 113 (43.6%) *
Number of immature GV oocytes 45 (23.0%) 74 (28.6%)

Non-significant differences in results of intracytoplasmic sperm injection (ICSI) cycles (fertilized oocytes, non-cleaved zygotes, cleavage embryos) on in vitro matured oocytes of patients with fertility problems regarding the number of immature (germinal vesicle [GV]) oocytes

ICSI cycles (n = 17) ≤ 30% GV oocytes ≥ 31% GV oocytes
Female age (years) 34.4 ± 3.0 34.3 ± 5.6
Number of microinjected oocytes 16 33
Fertilized oocytes 11 (69.0%) 16 (48.5%)
Non-cleaved zygotes 0 (0%) 4 (25.0%)
Cleavage embryos 11 (100%) 12 (75%)

Yeo W, Pang E, Liem GS, Suen JJS, Ng RYW, Yip CCH, et al. Menopausal symptoms in relationship to breast cancer-specific quality of life after adjuvant cytotoxic treatment in young breast cancer survivors. Health Qual Life Outcomes 2020; 18: 24. doi: 10.1186/s12955-020-1283-xYeo W Pang E Liem GS Suen JJS Ng RYW Yip CCH et al Menopausal symptoms in relationship to breast cancer-specific quality of life after adjuvant cytotoxic treatment in young breast cancer survivors Health Qual Life Outcomes 2020 18 24 10.1186/s12955-020-1283-xOpen DOISearch in Google Scholar

Silvestris E, Dellino M, Cafforio P, Paradiso AV, Cormio G, D'Oronzo S. Breast cancer: an update on treatment-related infertility. J Cancer Res Clin Oncol 2020; 146: 647-57. doi: 10.1007/s00432-020-03136-7Silvestris E Dellino M Cafforio P Paradiso AV Cormio G D'Oronzo S Breast cancer: an update on treatment-related infertility J Cancer Res Clin Oncol 2020 146 647 57 10.1007/s00432-020-03136-7Open DOISearch in Google Scholar

Felicetti F, Castiglione A, Biasin E, Fortunati N, Dionisi-Vici M, Matarazzo P, et al. Effects of treatments on gonadal function in long-term survivors of pediatric hematologic malignancies: a cohort study. Pediatr Blood Cancer 2020; 67: e28709. doi: 10.1002/pbc.28709Felicetti F Castiglione A Biasin E Fortunati N Dionisi-Vici M Matarazzo P et al Effects of treatments on gonadal function in long-term survivors of pediatric hematologic malignancies: a cohort study Pediatr Blood Cancer 2020 67 e28709 10.1002/pbc.28709Open DOISearch in Google Scholar

Yeganeh L, Boyle JA, Gibson-Helm M, Teede H, Vincent AJ. Women's perspectives of early menopause: development of a word cloud. Climacteric 2020; 23: 417-20. doi: 10.1080/13697137.2020.1730318Yeganeh L Boyle JA Gibson-Helm M Teede H Vincent AJ Women's perspectives of early menopause: development of a word cloud Climacteric 2020 23 417 20 10.1080/13697137.2020.1730318Open DOISearch in Google Scholar

Delattre S, Segers I, Van Moer E, Drakopoulos P, Mateizel I, Enghels L, et al. Combining fertility preservation procedures to spread the eggs across different baskets: a feasibility study. Hum Reprod 2020; 35: 2524-36. doi: 10.1093/humrep/deaa193.Delattre S Segers I Van Moer E Drakopoulos P Mateizel I Enghels L et al Combining fertility preservation procedures to spread the eggs across different baskets: a feasibility study Hum Reprod 2020 35 2524 36 10.1093/humrep/deaa193Open DOISearch in Google Scholar

Dinas KD. Fertility counseling and preservation for breast cancer patients. Adv Exp Med Biol 2020; 1252: 181-87. doi: 10.1007/978-3-030-41596-9_25Dinas KD Fertility counseling and preservation for breast cancer patients Adv Exp Med Biol 2020 1252 181 87 10.1007/978-3-030-41596-9_25Open DOISearch in Google Scholar

Bénard J, Duros S, El Hachem H, Sonigo C, Sifer C, Grynberg M. Freezing oocytes or embryos after controlled ovarian hyperstimulation in cancer patients: the state of the art. Future Oncol 2016; 12: 1731-41. doi: 10.2217/fon-2016-0095Bénard J Duros S El Hachem H Sonigo C Sifer C Grynberg M Freezing oocytes or embryos after controlled ovarian hyperstimulation in cancer patients: the state of the art Future Oncol 2016 12 1731 41 10.2217/fon-2016-0095Open DOISearch in Google Scholar

de Pedro M, Otero B, Martín B. Fertility preservation and breast cancer: a review. Ecancer 2015; 9: 503. doi: 10.3332/ecancer.2015.503de Pedro M Otero B Martín B Fertility preservation and breast cancer: a review Ecancer 2015 9 503 10.3332/ecancer.2015.503Open DOISearch in Google Scholar

Kasum M, Beketić-Orešković L, Peddi PF, Orešković S, Johnson RH. Fertility after breast cancer treatment. Eur J Obstet Gynecol Reprod Biol 2014; 173: 13-8. doi: 10.1016/j.ejogrb.2013.11.009Kasum M Beketić-Orešković L Peddi PF Orešković S Johnson RH Fertility after breast cancer treatment Eur J Obstet Gynecol Reprod Biol 2014 173 13 8 10.1016/j.ejogrb.2013.11.009Open DOISearch in Google Scholar

Peccatori FA, Pup LD, Salvagno F, Guido M, Sarno MA, Revelli A, et al. Fertility preservation methods in breast cancer. Breast Care 2012; 7: 197202. doi: 10.1159/000339671Peccatori FA Pup LD Salvagno F Guido M Sarno MA Revelli A et al Fertility preservation methods in breast cancer Breast Care 2012 7 197202 10.1159/000339671Open DOISearch in Google Scholar

Redig AJ, Brannigan R, Stryker SJ, Woodruff TK, Jeruss JS. Incorporating fertility preservation into the care of young oncology patients. Cancer 2011; 117: 4-10. doi: 10.1002/cncr.25398Redig AJ Brannigan R Stryker SJ Woodruff TK Jeruss JS Incorporating fertility preservation into the care of young oncology patients Cancer 2011 117 4 10 10.1002/cncr.25398Open DOISearch in Google Scholar

Meirow D. Reproduction post-chemotherapy in young cancer patients. Mol Cell Endocrinol 2000; 169: 123-31. doi: 10.1016/s0303-7207(00)00365-8Meirow D Reproduction post-chemotherapy in young cancer patients Mol Cell Endocrinol 2000 169 123 31 10.1016/s0303-7207(00)00365-8Open DOISearch in Google Scholar

Specchia C, Baggiani A, Immediata V, Ronchetti C, Cesana A, Smeraldi A, et al. Oocyte cryopreservation in oncological patients: eighteen years’ experience of a tertiary care referral center. Front Endocrinol 2019; 10: 600. doi: 10.3389/fendo.2019.00600Specchia C Baggiani A Immediata V Ronchetti C Cesana A Smeraldi A et al Oocyte cryopreservation in oncological patients: eighteen years’ experience of a tertiary care referral center Front Endocrinol 2019 10 600 10.3389/fendo.2019.00600Open DOISearch in Google Scholar

Gook DA, Edgar DH. Cryopreservation of female reproductive potential. Best Pract Res Clin Obstet Gynaecol 2019; 55: 23-36. doi: 10.1016/j.bpobgyn.2018.08.005Gook DA Edgar DH Cryopreservation of female reproductive potential Best Pract Res Clin Obstet Gynaecol 2019 55 23 36 10.1016/j.bpobgyn.2018.08.005Open DOISearch in Google Scholar

Cobo A, García-Velasco J, Domingo J, Pellicer A, Remohí J. Elective and oncofertility preservation: factors related to IVF outcomes. Hum Reprod 2018; 33: 2222-31. doi: 10.1093/humrep/dey321Cobo A García-Velasco J Domingo J Pellicer A Remohí J Elective and oncofertility preservation: factors related to IVF outcomes Hum Reprod 2018 33 2222 31 10.1093/humrep/dey321Open DOISearch in Google Scholar

Dolmans MM, Donnez J. Fertility preservation in women for medical and social reasons: oocytes vs ovarian tissue. Best Pract Res Clin Obstet Gynaecol 2020; 21: S1521-6934(20)30122-X. doi: 10.1016/j.bpobgyn.2020.06.011Dolmans MM Donnez J Fertility preservation in women for medical and social reasons: oocytes vs ovarian tissue Best Pract Res Clin Obstet Gynaecol 2020 21 S1521 6934 (20)30122-X 10.1016/j.bpobgyn.2020.06.011Open DOISearch in Google Scholar

Khalili MA, Shahedi A, Ashourzadeh S, Nottola SA, Macchiarelli G, Palmerini MG. Vitrification of human immature oocytes before and after in vitro maturation: a review. J Assist Reprod Genet 2017; 34: 1413-26. doi: 10.1007/s10815-017-1005-4Khalili MA Shahedi A Ashourzadeh S Nottola SA Macchiarelli G Palmerini MG Vitrification of human immature oocytes before and after in vitro maturation: a review J Assist Reprod Genet 2017 34 1413 26 10.1007/s10815-017-1005-4Open DOISearch in Google Scholar

Ata B, Chian RC, Tan SL. Cryopreservation of oocytes and embryos for fertility preservation for female cancer patients. Best Pract Res Clin Obstet Gynaecol 2010; 24: 101-12. doi: 10.1016/j.bpobgyn.2009.11.007Ata B Chian RC Tan SL Cryopreservation of oocytes and embryos for fertility preservation for female cancer patients Best Pract Res Clin Obstet Gynaecol 2010 24 101 12 10.1016/j.bpobgyn.2009.11.007Open DOISearch in Google Scholar

El Hachem H, Atallah D, Grynberg M. Fertility preservation in breast cancer patients. Future Oncol 2014; 10: 1767-77. doi: 10.2217/fon.14.55El Hachem H Atallah D Grynberg M Fertility preservation in breast cancer patients Future Oncol 2014 10 1767 77 10.2217/fon.14.55Open DOISearch in Google Scholar

Muñoz E, Domingo J, De Castro G, Lorenzo I, García-Velasco JA, Bellver J, et al. Ovarian stimulation for oocyte vitrification does not modify disease-free survival and overall survival rates in patients with early breast cancer. Reprod Biomed Online 2019; 39: 860-67. doi: 10.1016/j.rbmo.2019.07.003Muñoz E Domingo J De Castro G Lorenzo I García-Velasco JA Bellver J et al Ovarian stimulation for oocyte vitrification does not modify disease-free survival and overall survival rates in patients with early breast cancer Reprod Biomed Online 2019 39 860 67 10.1016/j.rbmo.2019.07.003Open DOISearch in Google Scholar

Rodgers RJ. Fertility preservation in breast cancer patients. Minerva Ginecol 2019; 71: 196-206. doi: 10.23736/S0026-4784.19.04409-5Rodgers RJ Fertility preservation in breast cancer patients Minerva Ginecol 2019 71 196 206 10.23736/S0026-4784.19.04409-5Open DOISearch in Google Scholar

Grynberg M, Poulain M, le Parco S, Sifer C, Fanchin R, Frydman N. Similar in vitro maturation rates of oocytes retrieved during the follicular or luteal phase offer flexible options for urgent fertility preservation in breast cancer patients. Hum Reprod 2016; 31: 623-9. doi: 10.1093/humrep/dev325Grynberg M Poulain M le Parco S Sifer C Fanchin R Frydman N Similar in vitro maturation rates of oocytes retrieved during the follicular or luteal phase offer flexible options for urgent fertility preservation in breast cancer patients Hum Reprod 2016 31 623 9 10.1093/humrep/dev325Open DOISearch in Google Scholar

Grynberg M, Mayeur Le Bras A, Hesters L, Gallot V, Frydman N. First birth achieved after fertility preservation using vitrification of in vitro matured oocytes in a woman with breast cancer. Ann Oncol 2020; 31: 541-42. doi: 10.1016/j.annonc.2020.01.005Grynberg M Mayeur Le Bras A Hesters L Gallot V Frydman N First birth achieved after fertility preservation using vitrification of in vitro matured oocytes in a woman with breast cancer Ann Oncol 2020 31 541 42 10.1016/j.annonc.2020.01.005Open DOISearch in Google Scholar

World Health Organisation. WHO laboratory manual for the examination and processing of human semen. Geneva: WHO Press; 2010.World Health Organisation WHO laboratory manual for the examination and processing of human semen Geneva WHO Press 2010Search in Google Scholar

Stimpfel M, Vrtacnik-Bokal E, Virant-Klun I. No difference in mitochondrial distribution is observed in human oocytes after cryopreservation. Arch Gynecol Obstet 2017; 296: 373-81. doi: 10.1007/s00404-017-4428-3Stimpfel M Vrtacnik-Bokal E Virant-Klun I No difference in mitochondrial distribution is observed in human oocytes after cryopreservation Arch Gynecol Obstet 2017 296 373 81 10.1007/s00404-017-4428-3Open DOISearch in Google Scholar

Virant-Klun I, Bauer C, Ståhlberg A, Kubista M, Skutella T. Human oocyte maturation in vitro is improved by co-culture with cumulus cells from mature oocytes. Reprod Biomed Online 2018; 36: 508-23. doi: 10.1016/j.rbmo.2018.01.011Virant-Klun I Bauer C Ståhlberg A Kubista M Skutella T Human oocyte maturation in vitro is improved by co-culture with cumulus cells from mature oocytes Reprod Biomed Online 2018 36 508 23 10.1016/j.rbmo.2018.01.011Open DOISearch in Google Scholar

Stimpfel M, Verdenik I, Zorn B, Virant-Klun I. Magnetic-activated cell sorting of non-apoptotic spermatozoa improves the quality of embryos according to female age: a prospective sibling oocyte study. J Assist Reprod Genet 2018; 35: 1665-74. doi:10.1007/s10815-018-1242-1Stimpfel M Verdenik I Zorn B Virant-Klun I Magnetic-activated cell sorting of non-apoptotic spermatozoa improves the quality of embryos according to female age: a prospective sibling oocyte study J Assist Reprod Genet 2018 35 1665 74 10.1007/s10815-018-1242-1Open DOISearch in Google Scholar

ESHRE Special Interest Group of Embryology and Alpha Scientists in Reproductive Medicine. The Vienna consensus: report of an expert meeting on the development of art laboratory performance indicators. Hum Reprod Open 2017; 2017: 1-17. doi: 10.1093/hropen/hox011ESHRE Special Interest Group of Embryology and Alpha Scientists in Reproductive Medicine The Vienna consensus: report of an expert meeting on the development of art laboratory performance indicators Hum Reprod Open 2017 2017 1 17 10.1093/hropen/hox011Open DOISearch in Google Scholar

Lefebvre T, Mirallié S, Leperlier F, Reignier A, Barrière P, Fréour T. Ovarian reserve and response to stimulation in women undergoing fertility preservation according to malignancy type. Reprod Biomed Online 2018; 37: 201-7. doi: 10.1016/j.rbmo.2018.04.047Lefebvre T Mirallié S Leperlier F Reignier A Barrière P Fréour T Ovarian reserve and response to stimulation in women undergoing fertility preservation according to malignancy type Reprod Biomed Online 2018 37 201 7 10.1016/j.rbmo.2018.04.047Open DOISearch in Google Scholar

Nordan T, Thomas AM, Ginsburg ES, Wen PY, Dolinko AV, Bortoletto P. Fertility preservation outcomes in women with gliomas: a retrospective case-control study. J Neurooncol 2020; 147: 371-76. doi: 10.1007/s11060-020-03429-4Nordan T Thomas AM Ginsburg ES Wen PY Dolinko AV Bortoletto P Fertility preservation outcomes in women with gliomas: a retrospective case-control study J Neurooncol 2020 147 371 76 10.1007/s11060-020-03429-4Open DOISearch in Google Scholar

Malacarne E, Devesa M, Martinez F, Rodriguez I, Coroleu B. COH outcomes in breast cancer patients for fertility preservation: a comparison with the expected response by age. J Assist Reprod Genet 2020; 37: 3069-76. doi: 10.1007/s10815-020-01944-xMalacarne E Devesa M Martinez F Rodriguez I Coroleu B COH outcomes in breast cancer patients for fertility preservation: a comparison with the expected response by age J Assist Reprod Genet 2020 37 3069 76 10.1007/s10815-020-01944-xOpen DOISearch in Google Scholar

Grynberg M, Dagher Hayeck B, Papanikolaou EG, Sifer C, Sermondade N, Sonigo C. BRCA1/2 gene mutations do not affect the capacity of oocytes from breast cancer candidates for fertility preservation to mature in vitro. Hum Reprod 2019; 34: 374-79. doi: 10.1093/humrep/dey358Grynberg M Dagher Hayeck B Papanikolaou EG Sifer C Sermondade N Sonigo C BRCA1/2 gene mutations do not affect the capacity of oocytes from breast cancer candidates for fertility preservation to mature in vitro Hum Reprod 2019 34 374 79 10.1093/humrep/dey358Open DOISearch in Google Scholar

Gunnala V, Fields J, Irani M, D'Angelo D, Xu K, Schattman G, et al. BRCA carriers have similar reproductive potential at baseline to noncarriers: comparisons in cancer and cancer-free cohorts undergoing fertility preservation. Fertil Steril 2019; 111: 363-71. doi: 10.1016/j.fertnstert.2018.10.014Gunnala V Fields J Irani M D'Angelo D Xu K Schattman G et al BRCA carriers have similar reproductive potential at baseline to noncarriers: comparisons in cancer and cancer-free cohorts undergoing fertility preservation Fertil Steril 2019 111 363 71 10.1016/j.fertnstert.2018.10.014Open DOISearch in Google Scholar

Moria A, Das M, Shehata F, Holzer H, Son WY, Tulandi T. Ovarian reserve and oocyte maturity in women with malignancy undergoing in vitro maturation treatment. Fertil Steril 2011; 95: 1621-3. doi: 10.1016/j.fertnstert.2010.12.041Moria A Das M Shehata F Holzer H Son WY Tulandi T Ovarian reserve and oocyte maturity in women with malignancy undergoing in vitro maturation treatment Fertil Steril 2011 95 1621 3 10.1016/j.fertnstert.2010.12.041Open DOISearch in Google Scholar

Volodarsky-Perel A, Cai E, Tulandi T, Son WY, Suarthana E, Buckett W. Influence of stage and grade of breast cancer on fertility preservation outcome in reproductive-aged women. Reprod Biomed Online 2020; 40: 215-22. doi: 10.1016/j.rbmo.2019.11.006Volodarsky-Perel A Cai E Tulandi T Son WY Suarthana E Buckett W Influence of stage and grade of breast cancer on fertility preservation outcome in reproductive-aged women Reprod Biomed Online 2020 40 215 22 10.1016/j.rbmo.2019.11.006Open DOISearch in Google Scholar

Balayla J, Tulandi T, Buckett W, Holzer H, Steiner N, Shrem G, et al. Outcomes of ovarian stimulation and fertility preservation in breast cancer patients with different hormonal receptor profiles. J Assist Reprod Genet 2020; 37: 913-21. doi: 10.1007/s10815-020-01730-9Balayla J Tulandi T Buckett W Holzer H Steiner N Shrem G et al Outcomes of ovarian stimulation and fertility preservation in breast cancer patients with different hormonal receptor profiles J Assist Reprod Genet 2020 37 913 21 10.1007/s10815-020-01730-9Open DOISearch in Google Scholar

Shalom-Paz E, Almog B, Shehata F, Huang J, Holzer H, Chian RC, et al. Fertility preservation for breast-cancer patients using IVM followed by oocyte or embryo vitrification. Reprod Biomed Online 2010; 21: 566-71. doi: 10.1016/j.rbmo.2010.05.003Shalom-Paz E Almog B Shehata F Huang J Holzer H Chian RC et al Fertility preservation for breast-cancer patients using IVM followed by oocyte or embryo vitrification Reprod Biomed Online 2010 21 566 71 10.1016/j.rbmo.2010.05.003Open DOISearch in Google Scholar

Liu Z, Liang G, Tan L, Su AN, Jiang W, Gong C. High-efficient screening method for identification of key genes in breast cancer through microarray and bioinformatics. Anticancer Res 2017; 37: 4329-35. doi: 10.21873/anticanres.11826Liu Z Liang G Tan L Su AN Jiang W Gong C High-efficient screening method for identification of key genes in breast cancer through microarray and bioinformatics Anticancer Res 2017 37 4329 35 10.21873/anticanres.11826Open DOISearch in Google Scholar

Cohen Y, Tannus S, Volodarsky-Perel A, Son WY, Tulandi T, Buckett W. Added benefit of immature oocyte maturation for fertility preservation in women with malignancy. Reprod Sci 2020; 27: 2257-64. doi: 10.1007/s43032-020-00245-zCohen Y Tannus S Volodarsky-Perel A Son WY Tulandi T Buckett W Added benefit of immature oocyte maturation for fertility preservation in women with malignancy Reprod Sci 2020 27 2257 64 10.1007/s43032-020-00245-zOpen DOISearch in Google Scholar

Chatroudi MH, Khalili MA, Ashourzadeh S, Anbari F, Shahedi A, Safari S. Growth differentiation factor 9 and cumulus cell supplementation in in vitro maturation culture media enhances the viability of human blastocysts. Clin Exp Reprod Med 2019; 46: 166-72. doi: 10.5653/cerm.2019.00402Chatroudi MH Khalili MA Ashourzadeh S Anbari F Shahedi A Safari S Growth differentiation factor 9 and cumulus cell supplementation in in vitro maturation culture media enhances the viability of human blastocysts Clin Exp Reprod Med 2019 46 166 72 10.5653/cerm.2019.00402Open DOISearch in Google Scholar

Sacha CR, Kaser DJ, Farland LV, Srouji S, Missmer SA, Racowsky C. The effect of short-term exposure of cumulus-oocyte complexes to in vitro maturation medium on yield of mature oocytes and usable embryos in stimulated cycles. J Assist Reprod Genet 2018; 35: 841-49. doi: 10.1007/s10815-018-1155-zSacha CR Kaser DJ Farland LV Srouji S Missmer SA Racowsky C The effect of short-term exposure of cumulus-oocyte complexes to in vitro maturation medium on yield of mature oocytes and usable embryos in stimulated cycles J Assist Reprod Genet 2018 35 841 49 10.1007/s10815-018-1155-zOpen DOISearch in Google Scholar

Pongsuthirak P, Songveeratham S, Vutyavanich T. Comparison of blastocyst and Sage media for in vitro maturation of human immature oocytes. Reprod Sci 2015; 22: 343-6. doi: 10.1177/1933719114542027Pongsuthirak P Songveeratham S Vutyavanich T Comparison of blastocyst and Sage media for in vitro maturation of human immature oocytes Reprod Sci 2015 22 343 6 10.1177/1933719114542027Open DOISearch in Google Scholar

Junk SM, Yeap D. Improved implantation and ongoing pregnancy rates after single-embryo transfer with an optimized protocol for in vitro oocyte maturation in women with polycystic ovaries and polycystic ovary syndrome. Fertil Steril 2012; 98: 888-92. doi: 10.1016/j.fertnstert.2012.06.055Junk SM Yeap D Improved implantation and ongoing pregnancy rates after single-embryo transfer with an optimized protocol for in vitro oocyte maturation in women with polycystic ovaries and polycystic ovary syndrome Fertil Steril 2012 98 888 92 10.1016/j.fertnstert.2012.06.055Open DOISearch in Google Scholar

Oktay K, Buyuk E, Rodriguez-Wallberg KA, Sahin G. In vitro maturation improves oocyte or embryo cryopreservation outcome in breast cancer patients undergoing ovarian stimulation for fertility preservation. Reprod Biomed Online 2010; 20: 634-8. doi: 10.1016/j.rbmo.2010.01.012Oktay K Buyuk E Rodriguez-Wallberg KA Sahin G In vitro maturation improves oocyte or embryo cryopreservation outcome in breast cancer patients undergoing ovarian stimulation for fertility preservation Reprod Biomed Online 2010 20 634 8 10.1016/j.rbmo.2010.01.012Open DOISearch in Google Scholar

D'Hondt C, Vanhoeij M, Van Moer E, Segers I, Fontaine C, Tournaye H, et al. Fertility preservation does not delay the initiation of chemotherapy in breast cancer patients treated with adjuvant or neo-adjuvant chemotherapy. Breast Cancer Res Treat 2020; 184: 433-44. doi: 10.1007/s10549-020-05858-1D'Hondt C Vanhoeij M Van Moer E Segers I Fontaine C Tournaye H et al Fertility preservation does not delay the initiation of chemotherapy in breast cancer patients treated with adjuvant or neo-adjuvant chemotherapy Breast Cancer Res Treat 2020 184 433 44 10.1007/s10549-020-05858-1Open DOISearch in Google Scholar

Huang JY, Chian RC, Gilbert L, Fleiszer D, Holzer H, Dermitas E, et al. Retrieval of immature oocytes from unstimulated ovaries followed by in vitro maturation and vitrification: A novel strategy of fertility preservation for breast cancer patients. Am J Surg 2010; 200: 177-83. doi: 10.1016/j.amjsurg.2009.04.004Huang JY Chian RC Gilbert L Fleiszer D Holzer H Dermitas E et al Retrieval of immature oocytes from unstimulated ovaries followed by in vitro maturation and vitrification: A novel strategy of fertility preservation for breast cancer patients Am J Surg 2010 200 177 83 10.1016/j.amjsurg.2009.04.004Open DOISearch in Google Scholar

Oktay K, Demirtas E, Son WY, Lostritto K, Chian RC, Tan SL. In vitro maturation of germinal vesicle oocytes recovered after premature luteinizing hormone surge: description of a novel approach to fertility preservation. Fertil Steril 2008; 89: 228.e19-22. doi: 10.1016/j.fertnstert.2007.02.028Oktay K Demirtas E Son WY Lostritto K Chian RC Tan SL In vitro maturation of germinal vesicle oocytes recovered after premature luteinizing hormone surge: description of a novel approach to fertility preservation Fertil Steril 2008 89 228 e19-22 10.1016/j.fertnstert.2007.02.028Open DOISearch in Google Scholar

Marklund A, Eloranta S, Wikander I, Kitlinski ML, Lood M, Nedstrand E, et al. Efficacy and safety of controlled ovarian stimulation using GnRH antagonist protocols for emergency fertility preservation in young women with breast cancer-a prospective nationwide Swedish multicenter study. Hum Reprod 2020; 35: 929-38. doi: 10.1093/humrep/deaa029Marklund A Eloranta S Wikander I Kitlinski ML Lood M Nedstrand E et al Efficacy and safety of controlled ovarian stimulation using GnRH antagonist protocols for emergency fertility preservation in young women with breast cancer-a prospective nationwide Swedish multicenter study Hum Reprod 2020 35 929 38 10.1093/humrep/deaa029Open DOISearch in Google Scholar

American Society for Reproductive Medicine. Fertility preservation in patients undergoing gonadotoxic therapy or gonadectomy: a committee opinion. Practice Committee of the American Society for Reproductive Medicine. Fertil Steril 2019; 112: 1022-33. doi: 10.1016/j.fertnstert.2019.09.013American Society for Reproductive Medicine Fertility preservation in patients undergoing gonadotoxic therapy or gonadectomy: a committee opinion Practice Committee of the American Society for Reproductive Medicine. Fertil Steril 2019 112 1022 33 10.1016/j.fertnstert.2019.09.013Open DOISearch in Google Scholar

Rose BI, Brown SE. A review of the physiology behind letrozole applications in infertility: are current protocols optimal? J Assist Reprod Genet 2020; 37: 2093-104. doi: 10.1007/s10815-020-01892-6Rose BI Brown SE A review of the physiology behind letrozole applications in infertility: are current protocols optimal? J Assist Reprod Genet 2020 37 2093 104 10.1007/s10815-020-01892-6Open DOISearch in Google Scholar

Santiquet NW, Greene AF, Becker J, Barfield JP, Schoolcraft WB, Krisher RL. A pre-in vitro maturation medium containing cumulus oocyte complex ligand-receptor signaling molecules maintains meiotic arrest, supports the cumulus oocyte complex and improves oocyte developmental competence. Mol Hum Reprod 2017; 23: 594-606. doi: 10.1093/molehr/gax032Santiquet NW Greene AF Becker J Barfield JP Schoolcraft WB Krisher RL A pre-in vitro maturation medium containing cumulus oocyte complex ligand-receptor signaling molecules maintains meiotic arrest, supports the cumulus oocyte complex and improves oocyte developmental competence Mol Hum Reprod 2017 23 594 606 10.1093/molehr/gax032Open DOISearch in Google Scholar

Walls ML, Hunter T, Ryan JP, Keelan JA, Nathan E, Hart RJ. In vitro maturation as an alternative to standard in vitro fertilization for patients diagnosed with polycystic ovaries: a comparative analysis of fresh, frozen and cumulative cycle outcomes. Hum Reprod 2015; 30: 88-96. doi: 10.1093/humrep/deu248Walls ML Hunter T Ryan JP Keelan JA Nathan E Hart RJ In vitro maturation as an alternative to standard in vitro fertilization for patients diagnosed with polycystic ovaries: a comparative analysis of fresh, frozen and cumulative cycle outcomes Hum Reprod 2015 30 88 96 10.1093/humrep/deu248Open DOISearch in Google Scholar

Walls ML, Hart R, Keelan JA, Ryan JP. Structural and morphologic differences in human oocytes after in vitro maturation compared with standard in vitro fertilization. Fertil Steril 2016; 106: 1392-98. doi: 10.1016/j.fertnstert.2016.08.014Walls ML Hart R Keelan JA Ryan JP Structural and morphologic differences in human oocytes after in vitro maturation compared with standard in vitro fertilization Fertil Steril 2016 106 1392 98 10.1016/j.fertnstert.2016.08.014Open DOISearch in Google Scholar

Roesner S, Dietrich JE, Weigert J, Montag M, Toth B, Strowitzki T. Time-lapse imaging reveals differences in growth dynamics of embryos after in vitro maturation compared with conventional stimulation. Fertil Steril 2017; 107: 606-12. doi: 10.1016/j.fertnstert.2016.12.026Roesner S Dietrich JE Weigert J Montag M Toth B Strowitzki T Time-lapse imaging reveals differences in growth dynamics of embryos after in vitro maturation compared with conventional stimulation Fertil Steril 2017 107 606 12 10.1016/j.fertnstert.2016.12.026Open DOISearch in Google Scholar

Belva F, Roelants M, Vermaning S, Desmyttere S, De Schepper J, Bonduelle M, et al. Growth and other health outcomes of 2-year-old singletons born after IVM versus controlled ovarian stimulation in mothers with polycystic ovary syndrome. Hum Reprod Open 2020; 2020: hoz043. doi: 10.1093/hropen/hoz043Belva F Roelants M Vermaning S Desmyttere S De Schepper J Bonduelle M et al Growth and other health outcomes of 2-year-old singletons born after IVM versus controlled ovarian stimulation in mothers with polycystic ovary syndrome Hum Reprod Open 2020 2020: hoz043 10.1093/hropen/hoz043Open DOISearch in Google Scholar

Yu EJ, Yoon TK, Lee WS, Park EA, Heo JY, Ko YK, et al. Obstetrical, neonatal, and long-term outcomes of children conceived from in vitro matured oo-cytes. Fertil Steril 2019; 112: 691-99. doi: 10.1016/j.fertnstert.2019.05.034Yu EJ Yoon TK Lee WS Park EA Heo JY Ko YK et al Obstetrical, neonatal, and long-term outcomes of children conceived from in vitro matured oo-cytes Fertil Steril 2019 112 691 99 10.1016/j.fertnstert.2019.05.034Open DOISearch in Google Scholar

Son WY, Henderson S, Cohen Y, Dahan M, Buckett W. Immature Oocyte for Fertility Preservation. Front Endocrinol 2019; 10: 464. doi: 10.3389/fendo.2019.00464Son WY Henderson S Cohen Y Dahan M Buckett W Immature Oocyte for Fertility Preservation Front Endocrinol 2019 10 464 10.3389/fendo.2019.00464Open DOISearch in Google Scholar

Shirasawa H, Terada Y. In vitro maturation of human immature oocytes for fertility preservation and research material. Reprod Med Biol 2017; 16: 25867. doi: 10.1002/rmb2.12042Shirasawa H Terada Y In vitro maturation of human immature oocytes for fertility preservation and research material Reprod Med Biol 2017 16 25867 10.1002/rmb2.12042Open DOISearch in Google Scholar

Recommended articles from Trend MD

Plan your remote conference with Sciendo