Empty follicle syndrome

Exome sequencing in genuine empty follicle syndrome: Novel candidate genes

OBJECTIVE(S)

Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved in an IVF cycle despite apparently normal follicular development and meticulous follicular aspiration following ovulation induction. The EFS is called genuine (gEFS) when the trigger administration is correct. The existence of gEFS is a subject of controversy, and it is quite rare with an undetermined etiology. Genetic defects in specific genes have been demonstrated to be responsible for this condition in some patients. Our objective was to identify novel genetic variants associated with gEFS.

STUDY DESIGN

We conducted a prospective observational study including 1,689 egg donors from July 2017 to February 2023. WES were performed in patients suffering gEFS.

RESULTS

Only 7 patients (0.41 %) exhibited gEFS after two ovarian stimulation cycles and we subsequently performed whole exome sequencing (WES) on these patients. Following stringent filtering, we identified 6 variants in 5 affected patients as pathogenic in new candidate genes which have not been previously associated with gEFS before, but which are involved in important biological processes related to folliculogenesis. These genetic variants included c.603_618del in HMMR, c.1025_1028del in LMNB1, c.1091-1G > A in TDG, c.607C > T in HABP2, c.100 + 2 T > C in HAPLN1 and c.3592_3593del in JAG2.

CONCLUSION

As a conclusion, we identified new candidate genes related to gEFS that expand the mutational spectrum of genes related to gEFS.This study show that WES might be an efficient tool to identify the genetic etiology of gEFS and provide further understanding of the pathogenic mechanism of gEFS.

The Implications of Double Human Chorionic Gonadotropin (hCG) Trigger on a Pseudo-Empty Follicle Syndrome Patient Seeking Infertility Treatment Through Assisted Reproductive Technology (ART)

In the field of assisted reproductive technology (ART), empty follicle syndrome (EFS) is a known condition in which no oocytes are found despite adequate follicular development, which leads to a troublesome situation for patients seeking infertility treatment. In this case study, an EFS patient seeking treatment for infertility at an in vitro fertilization (IVF) clinic was examined to determine the effects of employing a double human chorionic gonadotropin (hCG) trigger. The final oocyte maturation and retrieval are induced by using the double hCG trigger, which includes giving two doses of hCG. In this particular patient, the study looks at the results of follicular development, oocyte retrieval, fertilization rates, embryo quality, and pregnancy rates. The conclusion provides information on how well the double hCG trigger affects treatment outcomes for EFS patients. According to the results of this case study, the two-stage hCG trigger procedure is suggested to enhance the results of oocyte retrieval in the uncategorized EFS patient. In all cycles after the procedural change, the double trigger's application led to effective oocyte maturation and retrieval. The study also showed that the double hCG trigger procedure had no negative consequences on patient safety or ovarian response. There were also no signs of ovarian hyperstimulation syndrome (OHSS) or any other problems. Due to the higher likelihood of oocyte retrieval, the patient also reported better emotional health and less anxiety during subsequent treatment cycles. The positive result of this case study demonstrates the potential advantages of a double hCG trigger procedure in pseudo-EFS patients receiving IVF treatment. When handling EFS cases, this modified strategy may be used as a potential answer by infertility clinics. The effectiveness and safety of the double hCG trigger procedure still need to be confirmed by doing randomized controlled trials on larger populations in order to validate the result.

Case report: A novel homozygous variant in ZP3 is associated with human empty follicle syndrome

Empty follicle syndrome (EFS) is a rare condition in female infertility. It is characterized by the inability to retrieve oocytes from visibly large, normally developing follicles in the ovaries, despite ovarian stimulation. The genetic factors contributing to this syndrome remain unclear. This study focused on patients who underwent three consecutive ovarian stimulation procedures for oocyte retrieval but experienced unsuccessful outcomes, despite the presence of observable large follicles. Ultrasound examinations were conducted to assess follicular development during each procedure. In order to investigate potential genetic causes, we performed whole exome sequencing on peripheral blood samples from the patient. Interestingly, we identified that this patient carries a homozygous mutation in the ZP3 genes. Within the ZP3 gene, we identified a homozygous variant [NM_001110354.2, c.176T>A (p.L59H)] specifically located in the zona pellucida (ZP) domain. Further analysis, including bioinformatics methods and protein structure modeling, was carried out to investigate the conservation of the ZP3L59H variant across different species. This homozygous variant exhibited a high degree of conservation across various species. Importantly, the homozygous ZP3L59H variant was associated with the occurrence of empty follicle syndrome in affected female patients. The homozygous ZP3L59H variant represents a newly discovered genetic locus implicated in the development of human empty follicle syndrome. Our findings contribute to a deeper understanding of the role of zona pellucida-related genes in infertility and provide valuable insights for the genetic diagnosis of female infertility.

Unraveling the Puzzle: Oocyte Maturation Abnormalities (OMAS)

Oocyte maturation abnormalities (OMAS) are a poorly understood area of reproductive medicine. Much remains to be understood about how OMAS occur. However, current knowledge has provided some insight into the mechanistic and genetic origins of this syndrome. In this study, current classifications of OMAS syndromes are discussed and areas of inadequacy are highlighted. We explain why empty follicle syndrome, dysmorphic oocytes, some types of premature ovarian insufficiency and resistant ovary syndrome can cause OMAS. We discuss live births in different types of OMAS and when subjects can be offered treatment with autologous oocytes. As such, we present this review of the mechanism and understanding of OMAS to better lead the clinician in understanding this difficult-to-treat diagnosis.

Oocyte maturation abnormalities - A systematic review of the evidence and mechanisms in a rare but difficult to manage fertility pheneomina

A small proportion of infertile women experience repeated oocyte maturation abnormalities (OMAS). OMAS include degenerated and dysmorphic oocytes, empty follicle syndrome, oocyte maturation arrest (OMA), resistant ovary syndrome and maturation defects due to primary ovarian insufficiency. Genetic factors play an important role in OMAS but still need specifications. This review documents the spectrum of OMAS and to evaluate the multiple subtypes classified as OMAS. In this review, readers will be able to understand the oocyte maturation mechanism, gene expression and their regulation that lead to different subtypes of OMAs, and it will discuss the animal and human studies related to OMAS and lastly the treatment options for OMAs. Literature searches using PubMed, MEDLINE, Embase, National Institute for Health and Care Excellence were performed to identify articles written in English focusing on Oocyte Maturation Abnormalities by looking for the following relevant keywords. A search was made with the specified keywords and included books and documents, clinical trials, animal studies, human studies, meta-analysis, randomized controlled trials, reviews, systematic reviews and options written in english. The search detected 3,953 sources published from 1961 to 2021. After title and abstract screening for study type, duplicates and relevancy, 2,914 studies were excluded. The remaining 1,039 records were assessed for eligibility by full-text reading and 886 records were then excluded. Two hundred and twenty seven full-text articles and 0 book chapters from the database were selected for inclusion. Overall, 227 articles, one unpublished and one abstract paper were included in this final review. In this review study, OMAS were classified and extensively evaluatedand possible treatment options under the light of current information, present literature and ongoing studies. Either genetic studies or in vitro maturation studies that will be handled in the future will lead more informations to be reached and may make it possible to obtain pregnancies.

Antral follicle count, oocyte production and embryonic developmental competence of senescent Nellore (Bos indicus) cows

Information on the follicular population and oocyte quality of cows in the final period of reproductive life is scarce. The present study aimed to compare the antral follicle count (AFC), oocyte production and embryonic developmental competence of young versus long-lived and senescent Bos indicus beef cows. Nellore cows (Bos indicus) were classified into three groups according to age: young (4-9 years, n = 10), long-lived (14-17 years, n = 10) and senescent (17-23 years, n = 10). At a random time in the estrus cycle, the cows received cloprostenol sodium salt (0.5 mg, IM), estradiol benzoate (1 mg, IM) and an intravaginal P4 device (1.4 g). Five days later, the P4 devise was removed and oocyte collection (OPU1) was performed. A second OPU (OPU2) was performed 5 days after the first in order to aspirate only growing follicles. During each OPU, AFC and the number and quality of cumulus-oocyte complexes (COCs) were evaluated. Then, the COCs were placed in standard maturation medium (IVM), fertilized and incubated for 9 days. The data were subjected to ANOVA and Multinomial Logistic Regression. The AFC was smaller in long-lived and senescent cows in both OPU1 and OPU2 when compared to younger cows. There was no difference in AFC between OPU1 (19.9 ± 1.8) and OPU2 (17.6 ± 1.9) in young cows, however, more follicles were punctured in long-lived and senescent cows in OPU1 (12.0 ± 2.6 and 19.3 ± 4.6) than in OPU2 (9.2 ± 1.9 and 10.3 ± 2.3), respectively (P < 0.01). The numbers of COCs recovered from young cows (OPU1 = 14.2 ± 1.8; OPU2 = 8.4 ± 0.9) were higher than those obtained from long-lived cows (OPU1 = 5.9 ± 2.3; OPU2 = 4.3 ± 1.0) and senescent cows (OPU1 = 7.2 ± 3.0; OPU2 = 4.1 ± 1.7), respectively (P < 0.05). The cleavage rate did not differ between groups. However, the rate of blastocyst formation was higher for young (64.8%) and long-lived (65.0%) compared to senescent (16.5%) cows (P < 0.01). In conclusion our results indicate that the AFC is lower in long-lived and senescent cows compared with young cows. However, unlike in senescent cows, the embryonic development of long-lived cows is similar to that of young cows. This suggests that Nellore cows aged >17 years begin to have reduced embryonic development capacity due to ovarian aging.

Novel mutations in ZP1 and ZP2 cause primary infertility due to empty follicle syndrome and abnormal zona pellucida

PURPOSE

Mutations in the zona pellucida glycoprotein genes have been reported to be associated with empty follicle syndrome (EFS) and abnormal zona pellucida (ZP). In this study, we performed genetic analysis in the patients with female infertility due to abnormal zona pellucida and empty follicle syndrome to identify the disease-causing gene mutations in these patients.

METHODS

We characterized three patients from two independent families who had suffered from empty follicle syndrome or abnormal zona pellucida. Whole exome sequencing and Sanger sequencing were used to identify the mutations in the families. Western blot was used to check the expression of wild type and mutant disease genes.

RESULTS

We identified two novel mutations in these patients, including a novel compound heterozygous mutation (c.507delC, p. His170fs; c.239 G>A, p. Cys80Tyr and c.241 T>C, p. Tyr81His) in ZP1 gene and a compound mutation in ZP2 gene (c.860_861delTG, p.Val287fs and c.1924 C>T, p.Arg642Ter). Expression of the mutant ZP1 protein (p. Cys80Tyr and p. Tyr81His) is significantly decreased compared with the wild-type ZP1. Other three mutations produce truncated proteins.

CONCLUSIONS

Our findings expand the mutational spectrum of ZP1 and ZP2 genes associated with EFS and abnormal oocytes and provide new support for the genetic diagnosis of female infertility.

Characteristics of Empty Follicular Syndrome during In vitro Fertilization Embryo Transfer and its Association with Various Etiologies in Comparatively Young Patients

Background:

Nearly 0.6%–7% of patients undergoing in vitro fertilization embryo transfer (IVF ET) will not be able to yield any oocyte despite successful ovarian stimulation and this condition is called as empty follicular syndrome (EFS). EFS is a dreadful situation for clinicians as well as patients, seems to be an unavoidable clinical condition despite a proper ovarian stimulation.

Materials and Methods:

This was a retrospective observational study conducted at a tertiary hospital; 1103 patients who underwent IVF ET between January 2016 and May 2017 were included in the study.

Study Outcome:

To estimate the incidence of empty follicle syndrome (EFS) and to study the associated factors.

Results:

There were 53 (4.8%) cases of EFS out of 1103 cycles of IVF ET; 43 (3.9%) cases were false EFS and 10 (0.9%) cases were genuine EFS. Mean age of EFS group and oocyte retrieved group was 30.17 years and 29.12 years respectively. Recurrence rate of EFS during the next IVF cycle was 36.8%. Decreased ovarian reserve was associated with an increased chance of EFS (54.7%) with a recurrence rate as high as 57%.

Conclusion:

The incidence of EFS is not an uncommon clinical scenario; it depends upon ovarian reserve to a great extent. Young age is not immune for the occurrence of EFS as there is a similar incidence in comparatively younger age group in our study. EFS is seen in all etiological groups of infertility, but only respite is that there is a chance of about 63.2% oocyte retrieval during repeat IVF cycle.

Self-Detection of the LH Surge in Urine After GnRH Agonist Trigger in IVF-How to Minimize Failure to Retrieve Oocytes

Research question: Urine LH testing may be useful to confirm an LH surge after the GnRH agonist (GnRHa) trigger prior to oocyte retrieval in IVF. Design: A prospective cohort study, including oocyte donors undergoing ovarian stimulation, treated with a GnRHa trigger for final oocyte maturation. Urine LH testing was performed at home, 12 h after the GnRHa trigger. In the case of a negative result, serum LH and progesterone measurements were done that same day. Donors with no serum LH peak after trigger were re-scheduled using a dual trigger, with GnRHa and hCG. Results: Three hundred and fifty nine oocyte donors were included in the analysis. Three hundred and fifty six donors had positive urine LH tests, followed by oocyte retrieval. In one case, the LH test was positive, however, no oocytes were retrieved (false positive 1/356). Three LH tests were negative in urine: in one of these three cases, LH was tested again in blood, confirming an LH rise, consistent with an optimal response to the GnRHa trigger; in the other two cases, serum LH was <15 mUI/mL, after which the oocyte retrieval was re-scheduled for 36 h after an being re-triggered, resulting in the retrieval of 19 and 22 MII oocytes, respectively. Considering the cost analysis, it would be a significantly cost-saving strategy, as blood testing would have costed 14,840€ vs. only 185.5€ in urine LH kits. Conclusions: Urinary testing of the LH surge after GnRHa trigger is easy, safe, reliable, and convenient. In addition, LH urine testing allows identifying donors and patients who could benefit from a rescue hCG trigger after an unsuccessful GnRHa trigger.

Empty Follicle Syndrome: A Challenge to Physician

Background:

Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved from normally growing ovarian follicles after ovarian stimulation. It is a rare and frustrating condition of obscure etiology.

Objective:

The objective of this study was to estimate the incidence of EFS and study factors related to it.

Design:

This was a retrospective study.

Setting:

This study was conducted in hospital-based research center.

Methods:

In 1968 in vitro fertilization cycles from January 2010 to August 2016 were studied. Agonist, antagonist, and miniflare protocols were used for the stimulation.

Results:

The incidence of EFS is 2.38% (47/1968 cycles). Antagonist protocol group (76.59%, n = 36) had highest incidence of EFS (6.69%). Literature on EFS depicts decreased ovarian reserve (DOR) as the main cause, but only 4.25% of patients had DOR in our study. Interestingly, polycystic ovary syndrome and unexplained infertility were found in 31.9% of the cases. Serum anti-Müllerian hormone (AMH) levels (mean ± standard deviation [SD]) were 4.47 ± 3.54 ng/ml, and antral follicle count (AFC) was 15.30 ± 8.07 (mean ± SD) emphasizing that diminished ovarian reserve is not the main factor for EFS. All patients (n = 95) who underwent ovum pickup on day when any patient had EFS were taken as control. Patients with EFS were compared with controls. A statistically significant difference was not observed in serum AMH (P = 0.38) and AFC (P = 0.52).

Conclusion:

EFS is an uncommon event. Antagonist cycles have higher chances of empty follicle at ovum pickup. Looking at the profile of patients in this study, we conclude that EFS is not a manifestation of DOR.

Empty Follicle Syndrome Following GnRHa Trigger in PCOS Patients Undergoing IVF Cycles

BACKGROUND

The objective of this study was to analyze the incidence and the underlying mechanisms of empty follicle syndrome (EFS) occurring in gonadotropin releasing hormone agonist (GnRHa) triggered in in vitro fertilization (IVF) cycles with GnRH antagonist protocol in women with polycystic ovary syndrome (PCOS) of Indian origin. The study also intended to evaluate the cycle outcome following a rescue trigger.

METHODS

Retrospective cohort analysis of data was extracted from the hospital database of 271 PCOS patients who underwent IVF in antagonist protocol triggered with GnRHa from August 2014 to December 2016. All cases with failure to obtain oocytes following retrieval were analyzed. Continuous variables were expressed as mean±SD using t-test and Chi-squared test for categorical variables. A p<0.05 was considered statistically significant.

RESULTS

Incidence of EFS following GnRHa trigger was found to be 3.3%. False empty follicle syndrome (FEFS) accounted for majority of the cases (8/9=88.8%). Of the nine EFS, six cases were salvaged with a rescue trigger, resulted in transfer of reasonably good quality embryos in a frozen-thawed embryo replacement cycle achieving clinical pregnancy in three cases (3/6=50%).

CONCLUSION

Our experience with EFS cases following GnRHa, albeit small, given the rarity of its occurrence, suggests that majority of EFS are of false forms and can be effectively salvaged which results in reasonably favorable outcome.

Empty follicle syndrome revisited: definition, incidence, aetiology, early diagnosis and treatment

In this review, the definition, incidence and possible causes of empty follicle syndrome (EFS), including molecular mechanisms that may underlie the syndrome, are discussed, along with prevention and treatment options. EFS is the complete failure to retrieve oocytes after ovarian stimulation, despite apparently normal follicle development and adequate follicular steroidogenesis. Two variants of EFS have been described: the 'genuine' form (gEFS), which occurs in the presence of adequate circulating HCG levels at the time of oocyte aspiration, and the 'false' form (f-EFS), which is associated with circulating HCG below a critical threshold. Heterogeneous HCG concentration thresholds, however, have been used to define gEFS, and to date no standardization exist. The situation is unclear when GnRH-analogues are used for ovulation trigger, as the threshold circulating LH and progesterone levels used to define EFS as 'genuine' are not established. The cause of fEFS has been clearly identified as an error in HCG administration at the time of ovulation trigger; in contrast, the cause of gEFS is still unclear, although some pathogenetic hypotheses have been proposed. Optimal treatment and prognosis of these patients are still poorly understood. Large, systematic multi-centre studies are needed to increase the understanding of EFS.

Dual trigger for final oocyte maturation improves the oocyte retrieval rate of suboptimal responders to gonadotropin-releasing hormone agonist

OBJECTIVE

To identify the risk factors for suboptimal response to GnRH agonist (GnRH-a) trigger and evaluate the effect of hCG on the outcome of patients with suboptimal response to GnRH-a.

DESIGN

A retrospective data analysis.

SETTING

A tertiary-care academic medical center.

PATIENT(S)

A total of 8,092 women undergoing 8,970 IVF/intracytoplasmic sperm injection (ICSI) treatment cycles.

INTERVENTION(S)

All women underwent hMG + medroxyprogesterone acetate (MPA)/P treatment cycles during IVF/ICSI, which were triggered using a GnRH-a alone or in combination with hCG (1,000, 2,000, or 5,000 IU). Viable embryos were cryopreserved for later transfer.

MAIN OUTCOME MEASURE(S)

The rates of oocyte retrieval, mature oocytes, fertilization, and the number of oocytes retrieved, mature oocytes, and embryos frozen.

RESULT(S)

In total, 2.71% (243/8,970) of patients exhibited a suboptimal response to GnRH-a. The suboptimal responders (LH ≤15 mIU/mL) had a significantly lower oocyte retrieval rate (48.16% vs. 68.26%), fewer mature oocytes (4.10 vs. 8.29), and fewer frozen embryos (2.32 vs. 3.54) than the appropriate responders. Basal LH levels served as the single most valuable marker for differentiating suboptimal responders with the areas under the receiver operating curve of 0.805. Administering dual trigger (GnRH-a and hCG 1,000, 2,000, 5,000 IU) significantly increased oocyte retrieval rates (60.04% vs. 48.16%; 68.13% vs. 48.16%; and 65.76% vs. 48.16%, respectively) in patients with a suboptimal response.

CONCLUSION(S)

Basal LH level was useful predictor of the suboptimal response to GnRH-a trigger. Administrating dual trigger including 1,000 IU hCG for final oocyte maturation could improve the oocytes retrieval rate of GnRH-a suboptimal responder.

Empty Follicle Syndrome: The Possible Cause of Occurrence

OBJECTIVES

Empty follicle syndrome (EFS), although rare, is a disappointing condition in which no oocytes are retrieved from mature follicle after ovulation induction in in vitro fertilization (IVF) cycles. The aim of this study was to estimate the incidence and factors associated with EFS.

METHODS

All cycles resulting in EFS from May 2012 to September 2013 were retrospectively identified at a tertiary referral infertility center. Among the 3,356 cycles performed, 58 (1.7%) women who underwent their first IVF cycle and had no oocyte retrieval were enrolled in the study. Three different stimulation protocols (long, antagonist, and miniflare) were mainly used for induction of follicular growth. Data relating to the age, follicle stimulating hormone (FSH) level, anti-Müllerain hormone (AMH) level, and the number of ampules and follicles for each patient was obtained.

RESULTS

Out of 58 individuals, 10 (17.2%) showed false type and 48 (82.8%) showed genuine EFS. The most frequent findings in our study were diminished ovarian reserve, low anti-Müllerian hormone (AMH; ≤0.5 ng/mL), and less than four mature follicles, indicating EFS in 1.7% of the patients.

CONCLUSION

Low serum AMH levels and a small number of follicles after ovarian stimulation is the manifestation of diminished ovarian reserve. Thus, we suggest that EFS could be a manifestation of low ovarian reserve.

Is the time interval between HCG administration and oocyte retrieval associated with oocyte retrieval rate?

The aim of this study was to evaluate whether prolongation of the time interval between HCG administration and oocyte retrieval, from 36 h to 38 h, affects oocyte retrieval rate in women undergoing ovarian stimulation with gonadotrophins and GnRH antagonists for IVF. One hundred and fifty-six normo-ovulatory women were randomized to have oocyte retrieval performed 36 h (n = 78) or 38 h (n = 78) following HCG administration. Oocyte retrieval rate was defined as number of cumulus-oocyte-complex (COC) retrieved/follicle ≥ 11 mm present on day of HCG administration. No significant differences were observed between the groups regarding baseline characteristics. Moreover, no significant difference was observed between the groups regarding oocyte retrieval rate (difference: + 1.2%, 95% CI for difference between medians: -4.5 to +12.1). The median (95% CI for the median) was not significantly different between the groups regarding number of cumulus-oocyte-complexes (COCs) retrieved: 5.5 (5.0-7.0) versus 6.0 (5.0-6.2), respectively, and fertilization rates: 57.7% (50.0-66.7) versus 50.0% (44.8-65.5), respectively. Live birth rates were similar between the groups (20.5% versus 16.7%, RD: + 3.8%, 95% CI: -8.5 to +16.1, respectively). Prolongation of time interval between HCG administration and oocyte retrieval from 36 h to 38 h does not affect oocyte retrieval rate.

Predictive factors for oocyte retrieval failure in controlled ovarian hyperstimulation protocols: a retrospective observational cohort study

BACKGROUND

Oocyte retrieval failure following an ovarian hyperstimulation protocol is uncommon in assisted reproductive technology (ART) programs. We analyzed the predictive factors for oocyte retrieval failure following controlled ovarian hyperstimulation (COH) with gonadotropin-releasing hormone (GnRH) agonist and GnRH antagonist protocols in ART programs.

METHODS

This study was a retrospective cohort observational study. In total, 744 cycles from 361 patients who underwent controlled ovarian hyperstimulation with GnRH agonist long protocol or antagonist protocol were analyzed. Treatment cycles with oocyte retrieval failure and with one or more oocytes retrieved were compared to determine predictive factors for oocyte retrieval failure using univariate and multilevel multivariate logistic regression analyses.

RESULTS

Oocyte retrieval failure occurred in 38 cycles (5.1%). The oocyte retrieval failure rate of the GnRH antagonist protocol (8.1%) was significantly higher than that of the GnRH agonist long protocol (3.7%). On multilevel multivariate logistic analysis, cycles with GnRH antagonist protocol (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.05-8.96), estradiol level on the day of human chorionic gonadotropin (hCG) injection (OR 0.997, 95% CI 0.996-0.998), and luteinizing hormone (LH) level on the day of hCG injection (OR 1.19, 95% CI 1.06-1.33) were independent predictive factors for oocyte retrieval failure. The efficacy of estradiol and LH levels on the day of hCG injection for predicting oocyte retrieval failure was evaluated using receiver operating characteristic curves. In all cycles, the areas under the curve (AUCs) for estradiol and LH were 0.84 and 0.63, respectively, for all cycles; 0.84 and 0.52, respectively, for cycles with GnRH agonist long protocol; and 0.81 and 0.82, respectively, for cycles with GnRH antagonist protocol.

CONCLUSIONS

Our results suggest that in cycles with GnRH antagonist protocol, the levels of estradiol and LH on the day of hCG injection might be predictive factors for oocyte retrieval failure. This relationship may provide useful information to both patients and physicians for developing better COH protocols in ART programs.

Infertility and Immunocontraception based on zona pellucida

The zona pellucida (ZP) is an extracellular matrix surrounding ovarian oocytes, ovulated eggs and preimplantation embryos. It plays several important roles at different stages of reproduction. Its constituent glycoproteins are expressed specifically in the ovary. It is thus possible to produce autoantibodies to ZP proteins that interfere with reproductive functions including folliculogenesis, fertilization and implantation. First, this article describes the history of anti-ZP antibodies detected in women with idiopathic infertility. Second, the current relationship between anti-ZP antibodies and infertility is discussed in relation to assisted reproductive medicine. Third, we introduce the latest studies of animal experiments involving the ZP. Finally, immunocontraceptive vaccine development using various ZP antigens is reviewed.