Evidence for expression and functionality of FSH and LH/hCG receptors in human endometrium

The role of recombinant LH in ovarian stimulation: what's new?

It is widely recognized that luteinizing hormone (LH) activity is pivotal during folliculogenesis. Nonetheless, the use of LH during ovarian stimulation remains a matter of debate. Indeed, women with good LH function are able to sustain follicle growth and maturation during ovarian stimulation carried out with regimens based on follicle-stimulating hormone (FSH) alone. However, evidence exists that LH activity could be necessary in specific infertile subgroups undergoing assisted reproduction treatment (ART) who are characterized by a functional or constitutive LH deficiency. For instance, women with reduced sensitivity to gonadotropins, also called hypo-responders, usually present with a genetic condition that could impair the function of LH. Furthermore, women of advanced reproductive age present a less functional LH system and consequently reduced androgen production. Reduced ovarian sensitivity and advanced reproductive age represent the main criteria proposed by the POSEIDON group to identify women with impaired prognosis when undergoing ART. Hypogonadotropic hypogonadal women are characterized by undetectable LH levels, thus the addition of LH activity during stimulation is mandatory to achieve satisfactory follicular recruitment. The aim of the present review is to describe the role of recombinant LH in ovarian stimulation, identifying the specific infertile population for whom LH supplementation could improve the outcome of ART.

Frozen versus fresh embryo transfer in women with low prognosis for in vitro fertilisation treatment: pragmatic, multicentre, randomised controlled trial

OBJECTIVE

To test the hypothesis that a freeze-all strategy would increase the chance of live birth compared with fresh embryo transfer in women with low prognosis for in vitro fertilisation (IVF) treatment.

DESIGN

Pragmatic, multicentre, randomised controlled trial.

SETTING

Nine academic fertility centres in China.

PARTICIPANTS

838 women with a low prognosis for IVF treatment defined by ≤9 oocytes retrieved or poor ovarian reserve (antral follicle count <5 or serum anti-Müllerian hormone level <8.6 pmol/L).

INTERVENTIONS

Eligible participants were randomised (1:1) to undergo either frozen embryo transfer or fresh embryo transfer on the day of oocyte retrieval. Participants in the frozen embryo transfer group had all of their embryos cryopreserved and underwent frozen embryo transfer later. Participants in the fresh embryo transfer group underwent fresh embryo transfer after oocyte retrieval.

MAIN OUTCOME MEASURES

The primary outcome was live birth, defined as the delivery of neonates with a heartbeat and respiration at ≥28 weeks' gestation. Secondary outcomes were clinical pregnancy, singleton or twin pregnancy, pregnancy loss, ectopic pregnancy, birth weight, maternal and neonatal complications, and cumulative live birth after embryo transfers within one year after randomisation.

RESULTS

In an intention-to-treat analysis, the rate of live birth was lower in the frozen embryo transfer group than in the fresh embryo transfer group (32% (132 of 419) v 40% (168 of 419); relative ratio 0.79 (95% confidence interval 0.65 to 0.94); P=0.009). The frozen embryo group had a lower rate of clinical pregnancy than the fresh embryo group (39% (164 of 419) v 47% (197 of 419); 0.83 (0.71 to 0.97)). The cumulative live birth rate was lower in the frozen embryo transfer group compared with the fresh embryo transfer group (44% (185 of 419) v 51% (215 of 419), 0.86 (0.75 to 0.99)). No difference was observed in birth weight, incidence of obstetric complications, or risk of neonatal morbidities.

CONCLUSIONS

Fresh embryo transfer may be a better choice for women with low prognosis in terms of live birth rate compared with a freeze-all strategy. The treatment strategies that prevent fresh embryo transfers, such as accumulating embryos with back-to-back cycles or performing routine preimplantation genetic testing for aneuploidy, warrant further studies in women with a low prognosis.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2100050168.

Luteinizing hormone receptor knockout mouse: What has it taught us?

Luteinizing hormone (LH), along with its agonist choriongonadotropin (hCG) in humans, is the key hormone responsible for the tropic regulation of the gonadal function. LH and hCG act through their cognate receptor, the luteinizing hormone/choriongonadotropin receptor (LHCGR; more appropriately LHR in rodents lacking CG), located in the testis in Leydig cells and in the ovary in theca, luteal, and luteinizing granulosa cells. Low levels in LHCGR are also expressed in numerous extragonadal sites. Hypogonadism is observed in humans expressing inactivating mutations in the LHβ-subunit (LHB)and LHCGR genes, confirming the crucial role of LH and LHCGR in gonadal development and function. Unraveling of the LHR structure and the advent of gene manipulation techniques enabled the production of mouse models with inactivated LHR function, that is, the LHR knockout (LuRKO) mouse, some 20 years ago. This mouse model has thereafter been instrumental in various experimental settings, alone or combined with other genetically modified mouse models, in providing novel, and in some cases unexpected, details about the LH/LHR function. We will review here the salient findings of these studies.

Atlas of Fshr expression from novel reporter mice

The FSH-FSHR pathway has been considered an essential regulator in reproductive development and fertility. But there has been emerging evidence of FSHR expression in extragonadal organs. This poses new questions and long-term debates regarding the physiological role of the FSH-FSHR, and underscores the need for reliable, in vivo analysis of FSHR expression in animal models. However, conventional methods have proven insufficient for examining FSHR expression due to several limitations. To address this challenge, we developed Fshr-ZsGreen reporter mice under the control of Fshr endogenous promoter using CRISPR-Cas9. With this novel genetic tool, we provide a reliable readout of Fshr expression at single-cell resolution level in vivo and in real time. Reporter animals were also subjected to additional analyses,to define the accurate expression profile of FSHR in gonadal and extragonadal organs/tissues. Our compelling results not only demonstrated Fshr expression in intragonadal tissues but also, strikingly, unveiled notably increased expression in Leydig cells, osteoblast lineage cells, endothelial cells in vascular structures, and epithelial cells in bronchi of the lung and renal tubes. The genetic decoding of the widespread pattern of Fshr expression highlights its physiological relevance beyond reproduction and fertility, and opens new avenues for therapeutic options for age-related disorders of the bones, lungs, kidneys, and hearts, among other tissues. Exploiting the power of the Fshr knockin reporter animals, this report provides the first comprehensive genetic record of the spatial distribution of FSHR expression, correcting a long-term misconception about Fshr expression and offering prospects for extensive exploration of FSH-FSHR biology.

Clinical impact of endogenous luteinizing hormone in frozen-thawed embryo transfer during hormone replacement cycle without gonadotropin-releasing hormone analog coadministration: Effects on pregnancy outcomes

PURPOSE

To assess the correlation between serum luteinizing hormone (LH) levels preceding luteal replacement initiation and outcomes of frozen-thawed embryo transfer (FET) cycles during hormone replacement therapy (HRT) without co-administration of gonadotropin-releasing hormone (GnRH) analog.

METHODS

We retrospectively enrolled 490 FET cycles performed between March 2018 and May 2023. Patients were categorized into quartiles based on their serum LH levels preceding luteal replacement. Multivariate logistic regression analysis was performed, with clinical pregnancy and live birth rates as dependent variables. The independent variables included women's mean age, serum LH, and estradiol levels preceding luteal replacement, and endometrial thickness during transfer.

RESULTS

Mean age, serum estradiol, and LH levels preceding luteal replacement were 36.8 ± 0.2 years, 306.5 ± 7.7 pg/mL, and 10.3 ± 0.3 mIU/mL, respectively. The clinical pregnancy and live birth rates were 46.8% and 31.9%, respectively, and varied significantly between quartiles. Multivariate analysis revealed that younger age and higher LH levels were significantly associated with increased clinical pregnancy and live birth rates.

CONCLUSIONS

Endogenous LH may facilitate pregnancy within FET cycles under HRT without GnRH analogs by preparing the endometrium for implantation.

Gonadotropin-Releasing Hormone (GnRH) Agonist Protocol Improves Pregnancy Outcomes During In Vitro Fertilization (IVF) and Intracytoplasmic Sperm Injection (ICSI) Treatment in Young Infertile Women: A Retrospective Study

Objective The objective of this study was to determine if gonadotropin-releasing hormone agonist (GnRH-a) or gonadotropin-releasing hormone antagonist (GnRH-ant) protocols during in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment in young infertile women improve their pregnancy outcomes. Methodology We retrospectively reviewed the records of 876 young infertile women aged 20-35 years who underwent fresh embryo transfer in IVF/ICSI cycles. The data were collected from their initial visits to the reproductive medicine center of the Second Affiliated Hospital of Zhengzhou University between January 2019 and December 2022. We divided them into two groups according to the controlled ovarian hyperstimulation (COH) protocols: GnRH-a (n = 580) and GnRH-ant (n = 296). The primary outcome assessed in this study was the live birth rate. The secondary observation indicators included the total dose and duration of gonadotropin (Gn), total embryo transfer, day three (D3) embryo transfer, total two pro-nuclei (2PN) cleavage count, number of fertilizations, and implantation rate. Results The live birth rate had no clinical significance (P > 0.05). The total dose and duration of Gn stimulation in the GnRH-ant group were lower than in the GnRH-a group (P  < 0.05). The total embryo transfer, D3 embryo transfer, total cleavage count, total 2PN cleavage count, number of fertilizations, transfer, and mature oocytes in metaphase II (MII) of D3 embryos in the GnRH-a group were higher than those in the GnRH-ant group (P  < 0.05). The clinical pregnancy rate and implantation rate of the GnRH-a group were higher than those of the control group. Conclusions The total embryo transfer, D3 embryo transfer, total cleavage count, total 2PN cleavage count, number of fertilizations, transfer and MII of D3 embryos, clinical pregnancy, and implantation rates were significantly higher in the GnRH-a protocol group. The total dosage of Gn and duration of Gn stimulation were lower in the GnRH-ant group than in the GnRH-a group. These findings provide the basis for the selection of the COH protocol in normal Chinese ovarian response patients undergoing IVF/ICSI.

Enhancing endometrial receptivity: the roles of human chorionic gonadotropin in autophagy and apoptosis regulation in endometrial stromal cells

Inadequate endometrial receptivity often results in embryo implantation failure and miscarriage. Human chorionic gonadotropin (hCG) is a key signaling molecule secreted during early embryonic development, which regulates embryonic maternal interface signaling and promotes embryo implantation. This study aimed to examine the impact of hCG on endometrial receptivity and its underlying mechanisms. An exploratory study was designed, and endometrial samples were obtained from women diagnosed with simple tubal infertility or male factor infertile (n = 12) and recurrent implantation failure (RIF, n = 10). Using reverse transcription-quantitative PCR and western blotting, luteinizing hormone (LH)/hCG receptor (LHCGR) levels and autophagy were detected in the endometrial tissues. Subsequently, primary endometrial stromal cells (ESCs) were isolated from these control groups and treated with hCG to examine the presence of LHCGR and markers of endometrial receptivity (HOXA10, ITGB3, FOXO1, LIF, and L-selectin ligand) and autophagy-related factors (Beclin1, LC3, and P62). The findings revealed that the expressions of receptivity factors, LHCGR, and LC3 were reduced in the endometrial tissues of women with RIF compared with the control group, whereas the expression of P62 was elevated. The administration of hCG to ESCs specifically activated LHCGR, stimulating an increase in the endometrial production of HOXA10, ITGB3, FOXO1, LIF and L-selectin ligands. Furthermore, when ESCs were exposed to 0.1 IU/mL hCG for 72 h, the autophagy factors Beclin1 and LC3 increased within the cells and P62 decreased. Moreover, the apoptotic factor Bax increased and Bcl-2 declined. However, when small interfering RNA was used to knock down LHCGR, hCG was less capable of controlling endometrial receptivity and autophagy molecules in ESCs. In addition, hCG stimulation enhanced the phosphorylation of ERK1/2 and mTOR proteins. These results suggest that women with RIF exhibit lower levels of LHCGR and compromised autophagy function in their endometrial tissues. Thus, hCG/LHCGR could potentially improve endometrial receptivity by modulating autophagy and apoptosis.

Association between serum LH levels on hCG trigger day and live birth rate after fresh embryo transfer with GnRH antagonist regimen in different populations

Objective

To investigate whether serum LH levels on hCG trigger day are associated with live birth rate (LBR) after fresh embryo transfer with GnRH antagonist regimen in different populations.

Methods

This study was a retrospective study. A total of 3059 fresh embryo transfers were divided into three populations: predicted normal ovarian responders (NOR) (n=2049), patients with PCOS (n=533), and predicted poor ovarian responders (POR) (n=477). Each population was stratified into three groups based on LH levels: < 25th percentile, 25-75th percentile, and > 75th percentile. The primary outcome of the study was LBR, and secondary outcomes included implantation, clinical pregnancy, and early pregnancy loss rates. Univariable and multivariable regression analyses were performed to adjust for potential confounders.

Results

In NOR, compared to the reference group (>75th percentile), LBR was significantly lower in the < 25th percentile group (adjusted OR=0.662; 95%CI, 0.508-0.863) and 25-75th percentile group (adjusted OR=0.791; 95%CI, 0.633-0.988). In PCOS patients, LBR decreased significantly in the < 25th percentile group (41.4%) compared to the 25-75th percentile group (53.7%) and > 75th percentile group (56.1%). In addition, the LBR was lower in the < 25th percentile group (33.6%) compared with the 25-75th percentile group (43.4%) and the>75th percentile group (42.0%) in POR, but this was not statistically significant.

Conclusions

High serum LH levels are associated with increased LBR after fresh embryo transfer in GnRH antagonist cycles, which may be attributable to higher implantation rate. LH may be a predictor of whether to schedule fresh embryo transfer in IVF cycles for better clinical outcomes.

Ovulatory-cycle frozen embryo transfer: spontaneous or triggered ovulation and the impact of LH elevation at hCG triggering

The effect of the luteinizing hormone (LH) elevation before the human chorionic gonadotropin (hCG) trigger in ovulatory frozen-thawed embryo transfer (Ovu-FET) cycles has not been determined. We aimed to investigate whether triggering ovulation in Ovu-FET cycles affects the live birth rate (LBR), and the contribution of elevated LH at the time of hCG trigger. This retrospective study included Ovu-FET cycles performed in our center from August 2016 to April 2021. Modified Ovu-FET (hCG trigger) and true Ovu-FET (without hCG trigger) were compared. The modified group was divided according to whether hCG was administered, before or after LH increased to > 15 IU/L and was twice the baseline value. The modified (n = 100) and true (n = 246) Ovu-FET groups and both subgroups of the modified Ovu-FET, those who were triggered before (n = 67) or after (n = 33) LH elevation, had comparable characteristics at baseline. Comparison of true vs. modified Ovu-FET outcomes revealed similar LBR (35.4% vs. 32.0%; P = 0.62), respectively. LBR were similar between the modified Ovu-FET subgroups regardless of the hCG trigger timing (31.3% before vs. 33.3% after LH elevation; P = 0.84). In conclusion, LBR of Ovu-FET were not affected by hCG trigger or whether LH was elevated at the time of hCG trigger. These results add reassurance regarding hCG triggering even after LH elevation.

Gonadotropins as pharmacological agents in assisted reproductive technology and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrinopathy associated with subfertility/infertility and pregnancy complications. Most PCOS women opt for assisted reproductive technologies (ART) for successful conception; however, optimization of the relative doses of the gonadotropins [follicle-stimulating hormone (FSH), luteinizing hormone (LH)/human chorionic gonadotropin (hCG)] for appropriate steroidogenesis, without causing ovarian hyperstimulatory syndrome (OHSS), is challenging. Embryonic factors probably do not contribute to pregnancy loss in PCOS women, albeit hormonal imbalance impairs the metabolic microenvironment critical for oocyte maturation and endometrial receptivity. Certain clinical studies have confirmed the role of metabolic corrections in increasing the rate of pregnancy in PCOS women. This review focuses on the impact of untimely high LHCGR and/or LH levels on oocyte/embryo quality, pregnancy outcomes in ART, and exploring LHCGR as a potential drug target in PCOS women.

A novel role of follicle-stimulating hormone (FSH) in various regeneration-related functions of endometrial stem cells

Follicle-stimulating hormone (FSH) promotes the production and secretion of estrogen, which in turn stimulates the growth and maturation of ovarian follicles. Therefore, consecutive FSH treatment to induce ovarian hyperstimulation (superovulation) is still considered the most cost-effective option for the majority of assisted reproductive technologies (ARTs). However, a relatively high cancellation rate and subsequent low pregnancy outcomes (approximately 15%) are the most challenging aspects of this FSH-based ART. Currently, the main cause for this low implantation rate of FSH-based ART has not yet been revealed. Therefore, we hypothesized that these high cancellation rates with FSH-based superovulation protocols might be associated with the harmful effects of consecutive FSH treatment. Importantly, several recent studies have revealed that tissue-resident stem cell deficiency can significantly reduce cyclic endometrial regeneration and subsequently decrease the pregnancy outcome. In this context, we investigated whether FSH treatment could directly inhibit endometrial stem cell functions and consequently suppress endometrial regeneration. Consistent with our hypothesis, our results revealed for the first time that FSH could inhibit various regeneration-associated functions of endometrial stem cells, such as self-renewal, migration, and multilineage differentiation capacities, via the PI3K/Akt and ERK1/2 signaling pathways both in vitro and in vivo.

Follicle-stimulating hormone (FSH) is commonly administered to treat female infertility by stimulating the ovaries, but FSH treatment can also inhibit key cellular and physiological processes required for successful pregnancy. In the light of pregnancy outcomes as low as 15 percent after FSH-based assisted reproduction technologies, In-Sun Hong at Gachon University, Incheon, South Korea, and colleagues investigated the effects of FSH. Working with cultured human stem cells from the lining of the uterus, they found that FSH could inhibit multiple cellular regenerative functions that normally maintain this lining. They also identified a specific molecular signaling pathway involved in mediating these inhibitory effects. Studies in mice supported the cell culture results. The findings could help improve infertility treatment strategies by guiding research into methods to alleviate the unwanted effects of FSH.

In vitro fertilization cycle and embryo transfer outcomes in oligoanovulatory patients with hypothalamic hypogonadism vs. polycystic ovary syndrome and compared with normo-ovulatory patients

Objective

To study the difference in the live birth rates between anovulatory women with hypothalamic hypogonadism (HH) and those with polycystic ovary syndrome (PCOS) and normo-ovulatory women undergoing fresh embryo transfer or frozen embryo transfer (FET).

Design

Retrospective cohort study.

Setting

Academic medical center.

Patient(s)

Patients with oligoanovulation (HH, n = 47; PCOS, n = 533) and normo-ovulation (tubal factor infertility, n = 399) undergoing in vitro fertilization and intracytoplasmic sperm injection cycles from January 1, 2012, to June 30, 2019.

Intervention(s)

None.

Main Outcome Measure(s)

Live birth rate.

Result(s)

Patients with HH had longer stimulation durations than both patients with PCOS and tubal factor infertility. Patients with HH had fewer oocytes retrieved than patients with PCOS, but their numbers of blastocysts were similar. Patients with HH and tubal factor infertility had similar numbers of oocytes retrieved and blastocysts. In fresh embryo transfer cycles, the live birth rates were similar among patients with HH, PCOS, and tubal factor infertility (37.5% vs. 37.1% vs. 29.3%, respectively). When evaluating FET cycles, patients with HH had lower live birth rates than patients with PCOS (26.5% vs. 46.7%) and tubal factor infertility (42.6%).

Conclusion(s)

Live birth rates are similar among patients with HH, PCOS, and normo-ovulation undergoing fresh embryo transfer but are significantly lower in women with HH undergoing FET.

Novel roles of luteinizing hormone (LH) in tissue regeneration-associated functions in endometrial stem cells

Luteinizing hormone (LH) stimulates the synthesis and secretion of the key steroid hormone estrogen, which subsequently promotes ovarian follicular growth and development. Therefore, the administration of exogenous LH to achieve superovulation (multiple ovulations) and an LH surge is commonly used as the most effective therapeutic option in a majority of in vitro fertilization (IVF) clinics. However, a relatively low pregnancy rate (between 20% and 35%) is one of the most challenging aspects of LH-based infertility treatment. Furthermore, the major cause of this low pregnancy rate in LH-based infertility treatment remains unidentified. Recent studies have shown that endometrial stem cell loss or deficiency can significantly decrease tissue regeneration ability during the menstrual cycle and reduce endometrial receptivity. In this context, we postulated that the low pregnancy rates following LH-based ovarian hyperactivation may be the result of the adverse effects of consecutive exogenous LH administration on endometrial stem cells. To the best of our knowledge, this study revealed for the first time that in addition to its previously reported roles in stimulating ovarian functions through the pituitary-gonadal axis, LH brings about the extragonadal suppression of various tissue regeneration-associated functions in endometrial stem cells, such as self-renewal, migration ability, multilineage differentiation potential, and pluripotency/stemness, by inhibiting pro-survival Akt and ERK1/2 signaling pathways in vitro and in vivo, and as a consequence, it decreases the endometrial receptivity.

Intrauterine Instillation of Human Chorionic Gonadotropin with Intrauterine Insemination Catheter Around the Golden Time of Embryo Transfer Does Not Improve In Vitro Fertilization /Intracytoplasmic Sperm Injection Outcomes in Infertile Women: A Randomized Controlled Trial

BACKGROUND

We set out to explore the effect of intrauterine human chorionic gonadotropin (hCG) instillation by intrauterine insemination (IUI) catheter before embryo transfer (ET) on assisted reproductive technologies (ART) outcomes of infertile women.

METHODS

One hundred women with infertility who were scheduled for in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles were included in the study. They were randomly devoted to two groups: experimental (n= 50) and control (n= 50). In the experimental group, 500 IU hCG passed into the internal cervical orifice via IUI catheter within 15 minutes before the transfer of fresh or vitrified cleavage-stage embryos. The control group underwent the same ET procedure without prior injection of hCG.

RESULTS

None of the outcomes showed a statistically significant difference between the two groups. In the intervention and control groups, respectively, biochemical pregnancies rates were 26% and 18%, implantation rates were 13.5% and 8.6%, clinical pregnancies rates were 22% and 14%, ongoing pregnancies rates were 18% and 14%, and live birth rates were 14% and 12%.

CONCLUSION

Intrauterine injection of hCG via IUI catheter is not recommended in a clinical routine setting at this stage. Future efforts are warranted to further refine the applicability of this modality.

Expression and function of the luteinizing hormone choriogonadotropin receptor in human endometrial stromal cells

The human luteinising hormone choriogonadotropin receptor (LHCGR) is a G-protein coupled receptor activated by both human chorionic gonadotropin (hCG) and luteinizing hormone (LH), two structurally related gonadotropins with essential roles in ovulation and maintenance of the corpus luteum. LHCGR expression predominates in ovarian tissues where it elicits functional responses through cyclic adenosine mononucleotide (cAMP), Ca²⁺ and extracellular signal-regulated kinase (ERK) signalling. LHCGR expression has also been localized to the human endometrium, with purported roles in decidualization and implantation. However, these observations are contentious. In this investigation, transcripts encoding LHCGR were undetectable in bulk RNA sequencing datasets from whole cycling endometrial tissue and cultured human endometrial stromal cells (EnSC). However, analysis of single-cell RNA sequencing data revealed cell-to-cell transcriptional heterogeneity, and we identified a small subpopulation of stromal cells with detectable LHCGR transcripts. In HEK-293 cells expressing recombinant LHCGR, both hCG and LH elicited robust cAMP, Ca²⁺ and ERK signals that were absent in wild-type HEK-293 cells. However, none of these responses were recapitulated in primary EnSC cultures. In addition, proliferation, viability and decidual transformation of EnSC were refractory to both hCG and LH, irrespective of treatment to induce differentiation. Although we challenge the assertion that LHCGR is expressed at a functionally active level in the human endometrium, the discovery of a discrete subpopulation of EnSC that express LHCGR transcripts may plausibly account for the conflicting evidence in the literature.

Adverse impact of elevated serum progesterone and luteinizing hormone levels on the hCG trigger day on clinical pregnancy outcomes of modified natural frozen-thawed embryo transfer cycles

RESEARCH QUESTION

The relationship between serum progesterone (P) and luteinizing hormone (LH) levels on the human chorionic gonadotropin (hCG) trigger day and the clinical pregnancy outcomes in modified natural frozen-thawed embryo transfer (mNC-FET) cycles are controversial.

DESIGN

This was a retrospective study of 788 mNC-FET cycles. A smooth fitting curve and threshold effect analysis was performed to identify the effect of serum P and LH levels measured on the hCG day on the clinical pregnancy rate (CPR) and live birth rate (LBR) of mNC-FET cycles.

RESULTS

The CPR and LBR decreased significantly when the LH level on the hCG day was greater than or equal to 32 IU/L. Further subgroup analysis showed that the CPR decreased significantly when the P level on the hCG day was equal to or greater than 1 ng/mL. When the P level was lower (< 1 ng/mL), the patients with an LH level greater than or equal to 32 IU/L had reduced CPR and LBR in mNC-FET cycles.

CONCLUSION

Applying the hCG trigger on a day with a higher P level (≥ 1 ng/mL) leads to a decreased CPR and LBR. hCG administration with a higher LH level (≥ 32 IU/L) also leads to a decreased CPR and LBR in mNC-FET cycles when the P level is less than 1 ng/mL.

Low Endogenous LH on the COS Initiation Day of a GnRH-Agonist Regimen Increases the Risk of Early Pregnancy Loss and Adverse ART Outcomes

OBJECTIVE

To assess the impact of serum luteinizing hormone (LH) levels on the day of initiation of controlled ovarian stimulation (COS) after pituitary suppression on early pregnancy loss and assisted reproductive technology (ART) outcomes.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated hospital.

PATIENTS

A total of 9540 normogonadotrophic patients were treated with a GnRH agonist for in vitro fertilization (IVF). Based on the serum concentration of LH on the COS initiation day, patients were divided into low (<1 mIU/mL, n=2838), medium (1-1.49 mIU/mL, n=3357), or high (≥1.5 mIU/mL, n=3345) LH groups and received either fresh embryo transfer (ET) or frozen ET (women with high ovarian response, insufficient endometrial thickness, or requesting frozen ET). A total of 6279 cycles were fresh ET (1960, 2222, and 2097 in the low, medium, and high LH groups, respectively).

INTERVENTIONS

During IVF/ICSI, a GnRH agonist was used to suppress pituitary function in the midluteal phase or follicular phase, and then gonadotropin was used to induce COS.

MAIN OUTCOME MEASURES

The early pregnancy loss rate (ePLR) and live-birth rate (LBR) for fresh ET, as well as the cumulative ePLR and LBR for the entire ovarian stimulation cycle, were compared.

RESULTS

In the fresh ET cycles, the high, medium and low LH groups had an ePLR of 8.6%, 11.9% and 12.5%, respectively, and LBR of 42.1%, 37.9% and 37.5%, respectively. There were no significant differences in terms of clinical pregnancy rate (CPR), late pregnancy loss rate (lPLR), and ectopic pregnancy rate (EPR) among the three LH groups. For the entire ovarian stimulation cycle, the high LH group had a greater number of retrieved oocytes compared with the low and medium LH groups. Among the groups of high, medium and low LH, the cumulative CPR were 72.8%, 69.8% and 68.8%, respectively, and the cumulative LBR were 63.4%, 60.4% and 58.5%, respectively. There were no significant differences in the cumulative ePLR, lPLR, or EPR. After multivariable logistic regression, compared with the high LH group, the adjusted odds ratio of early pregnancy loss in the low and medium LH group were 1.429 (1.065-1.919, P = 0.018) and 1.389 (1.041-1.853, P = 0.026).

CONCLUSIONS

After pituitary suppression by a GnRH-agonist during IVF, a low LH level (<1.5 mIU/mL) on the COS initiation day was associated with adverse ART outcomes-including fewer oocytes, higher ePLR and lower LBR in fresh ET-and lower cumulative CPR and LBR in the entire ovarian-stimulation cycle. And LH on the COS initiation day was an independent factor affecting ePLR after multivariate regression.

GnRH agonist supplementation in hormone replacement therapy-frozen embryo transfer cycles: a randomized controlled trial

RESEARCH QUESTION

Will two boluses of gonadotrophin-releasing hormone agonist (GnRHa) during hormone replacement therapy-frozen embryo transfer (HRT-FET) cycles reduce the total pregnancy loss rate?

DESIGN

Randomized controlled trial including a total of 287 HRT-FET cycles performed between 2013 and 2019. After randomization participants allocated to the GnRHa group (n = 144) underwent a standard HRT protocol, supplemented with a total of two boluses of triptorelin 0.1 mg; one bolus 2 days before starting vaginal progesterone and one bolus on the 7th day of progesterone. The control group (n = 143) underwent a standard HRT-FET protocol only.

RESULTS

The intention-to-treat analysis showed no significant difference in total pregnancy loss between the GnRHa group and the control group (21% versus 33%; relative risk [RR] 0.63, 95% confidence interval [CI] 0.35-1.11), nor was the biochemical pregnancy loss per positive human chorionic gonadotrophin (HCG) significantly lower in the GnRHa group (12%, 8/67) compared with the control group (25%, 18/72) (RR 0.48, 95% CI 0.22-1.02). Participants with a live birth had a significantly higher mean progesterone concentration compared with participants without a live birth (25.0 ± 12.2 versus 23.8 ± 8.9 nmol/l; P = 0.001). Furthermore, a trend for a higher live birth rate (LBR) correlated with the highest oestradiol quartile concentration (oestradiol >0.957 nmol/l).

CONCLUSIONS

Although a difference of 14% in biochemical loss and 12% in total pregnancy loss in favour of GnRHa supplementation was seen this did not reach statistical difference. Luteal progesterone and oestradiol concentrations correlate with LBR in the HRT-FET cycle, emphasizing the importance of luteal serum progesterone and oestradiol monitoring.

An overview of FSH-FSHR biology and explaining the existing conundrums

FSH was first identified in 1930 and is central to mammalian reproduction. It is indeed intriguing that despite being researched upon for about 90 years, there is still so much more to learn about FSH-FSHR biology. The purpose of this review is to provide an overview of current understanding of FSH-FSHR biology, to review published data on biological and clinical relevance of reported mutations, polymorphisms and alternately spliced isoforms of FSHR. Tissue-resident stem/progenitor cells in multiple adult tissues including ovaries, testes and uterus express FSHR and this observation results in a paradigm shift in the field. The results suggest a direct action of FSH on the stem cells in addition to their well-studied action on Granulosa and Sertoli cells in the ovaries and testes respectively. Present review further addresses various concerns raised in recent times by the scientific community regarding extragonadal expression of FSHR, especially in cancers affecting multiple organs. Similar population of primitive and pluripotent tissue-resident stem cells expressing FSHR exist in multiple adult tissues including bone marrow and reproductive tissues and help maintain homeostasis throughout life. Any dysfunction of these stem cells results in various pathologies and they also most likely get transformed into cancer stem cells and initiate cancer. This explains why multiple solid as well as liquid tumors express OCT-4 and FSHR. More research efforts need to be focused on alternately spliced FSHR isoforms.

Endogenous, tissue-resident stem/progenitor cells in gonads and bone marrow express FSHR and respond to FSH via FSHR-3

Follicle stimulating hormone (FSH) is secreted by the anterior pituitary and acts on the germ cells indirectly through Granulosa cells in ovaries and Sertoli cells in the testes. Extragonadal action of FSH has been reported but is still debated. Adult tissues harbor two populations of stem cells including a reserve population of primitive, small-sized, pluripotent very small embryonic-like stem cells (VSELs) and slightly bigger, tissue-specific progenitors which include ovarian stem cells (OSCs) in ovaries, spermatogonial stem cells (SSCs) in testes, endometrial stem cells (EnSCs) in uterus and hematopoietic stem cells (HSCs) in the bone marrow. Data has accumulated in animal models showing FSHR expression on both VSELs and progenitors in ovaries, testes, uterus and bone marrow and eventually gets lost as the cells differentiate further. FSH exerts a direct action on the stem/progenitor cells via alternatively spliced FSHR-3 rather than the canonical FSHR-1. FSH stimulates VSELs to undergo asymmetrical cell divisions to self-renew and give rise to the progenitors that in turn undergo symmetrical cell divisions and clonal expansions followed by differentiation into specific cell types. Excessive self-renewal of VSELs results in cancer and this explains ubiquitous expression of embryonic markers including nuclear OCT-4 along with FSHR in cancerous tissues. Focus of this review is to compile published data to support this concept. FSHR expression in stem/progenitor cells was confirmed by immuno-fluorescence, Western blotting, in situ hybridization and by quantitative RT-PCR. Two different commercially available antibodies (Abcam, Santacruz) were used to confirm specificity of FSHR expression along with omission of primary antibody and pre-incubation of antibody with immunizing peptide as negative controls. Western blotting allowed detection of alternatively spliced FSHR isoforms. Oligoprobes and primers specific for Fshr-1 and Fshr-3 were used to study these alternately-sliced isoforms by in situ hybridization and their differential expression upon FSH treatment by qRT-PCR. To conclude, stem/progenitor cells in adult tissues express FSHR and directly respond to FSH via FSHR-3. These findings change the field of FSH-FSHR biology, call for paradigm shift, explain FSHR expression on cancer cells in multiple organs and provide straightforward explanations for various existing conundrums including extragonadal expression of FSHR.

Hsa-mir-548 family expression in human reproductive tissues

BACKGROUND

Hsa-miR-548ba expressed in ovarian granulosa cells targets PTEN and LIFR, which are essential for ovarian follicle activation and growth. The expression pattern of hsa-miR-548ba correlates with its host gene follicle-stimulating hormone receptor (FSHR), and FSH has a positive influence on hsa-miR-548ba expression. However, hsa-miR-548ba is a member of a large hsa-mir-548 family with potentially overlapping targets. The current study aims to investigate the co-expression of hsa-mir-548 family members in FSHR-positive reproductive tissues and to explore the potential co-regulation of pathways.

RESULTS

For the above-described analysis, small RNA sequencing data from public data repositories were used. Sequencing results revealed that hsa-miR-548ba was expressed at the highest level in the ovarian granulosa cells and uterine myometrial samples together with another twelve and one hsa-miR-548 family members, respectively. Pathway enrichment analysis of microRNA targets in the ovarian samples revealed the hsa-miR-548ba and hsa-miR-548b-5p co-regulation of RAB geranylgeranylation in mural granulosa cells. Moreover, other hsa-mir-548 family members co-regulate pathways essential for ovarian functions (PIP3 activates AKT signalling and signalling by ERBB4). In addition to hsa-miR-548ba, hsa-miR-548o-3p is expressed in the myometrium, which separately targets the peroxisome proliferator-activated receptor alpha (PPARA) pathway.

CONCLUSION

This study reveals that hsa-mir-548 family members are expressed in variable combinations in the reproductive tract, where they potentially fulfil different regulatory roles. The results provide a reference for further studies of the hsa-mir-548 family role in the reproductive tract.

Association between endogenous LH level prior to progesterone administration and live birth rate in artificial frozen-thawed blastocyst transfer cycles of ovulatory women

STUDY QUESTION

Is there an association between serum LH levels prior to progesterone administration and live birth rate (LBR) in artificial frozen-thawed embryo transfer (FET) cycles?

SUMMARY ANSWER

: Low serum LH levels on the day before progesterone initiation in artificial frozen-thawed blastocyst transfer cycles of ovulatory women are associated with a lower LBR.

WHAT IS KNOWN ALREADY

In artificial FET cycles, exogenous oestrogen and progesterone are administered sequentially to mimic the serum hormone pattern similar to the natural cycle. In oestrogen-only phase, the supplemental oestrogen causes thickening of the endometrium and is sometimes accompanied by a rise in serum LH. However, whether the endogenous LH level in artificial FET cycles is related to clinical outcomes remains unclear.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study including 3469 artificial frozen-thawed blastocyst transfer cycles was conducted at a tertiary-care academic medical centre between February 2014 and January 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 3469 frozen blastocyst transfer cycles were stratified into four groups based on the quartiles of serum LH level before progesterone initiation: <25th percentile (LH < 8.79 mIU/ml), 25-50th percentile (8.79 ≤ LH ≤ 13.91 mIU/ml), 51-75th percentile (13.91 < LH ≤ 20.75 mIU/ml) and >75th percentile (LH > 20.75 mIU/ml). The serum LH level >75th percentile group was considered as the reference group. Patients with polycystic ovarian syndrome or other ovulatory disorders were excluded from the study. We also excluded cycles with an endometrial thickness <7 mm before progesterone initiation and patients with intrauterine adhesions and uterine abnormalities. In order to avoid the interference of BMI, all patients were divided into two categories based on the overweight threshold: BMI <25 kg/m2 and ≥25 kg/m2, and the impacts of serum LH levels on LBR were investigated separately. Univariable and multivariable logistic regression analysis were performed to adjust for potential confounders. EmpowerStats software and R-project were used to build smooth curve fitting models.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared with the reference group, the implantation rate significantly decreased with low LH levels (<25th percentile) on the day before progesterone initiation (odds ratio [OR] = 0.74; 95% CI, 0.64-0.86; P = 0.001). Accounting for major covariates, low LH levels were associated with a relatively lower LBR (adjusted OR = 0.649; 95% CI, 0.531-0.794; P < 0.001), mainly due to a lower implantation rate, lower clinical pregnancy rate and higher pregnancy loss rate. Moreover, in the patients with BMI <25 kg/m2, low LH was associated with a lower LBR (P < 0.001); while in the overweight subgroup, LBR and LH were not correlated (P = 0.823).

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is its retrospective design. Owing to the relatively small number in the overweight group, the results of the overweight subgroup should be interpreted with caution.

WIDER IMPLICATIONS OF THE FINDINGS

The evidence provided in this study shows the importance of serum LH levels on the day before progesterone initiation in patients undergoing artificial FET cycles. Hypothalamic dysfunction may be one of the important causes of a relatively low LH, which is related to impaired pregnancy outcomes. Serum LH levels may be used as one of the clinical indicators to predict pregnancy outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

No funding and no competing interest were involved in this study.

TRIAL REGISTRATION NUMBER

NA.

Complementary and Alternative Medicine for the Treatment of Abnormal Endometrial Conditions in Women with PCOS: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

Endometrial lesions in patients with polycystic ovary syndrome (PCOS) exhibit complex pathological features, and these patients are at risk of both short-term and long-term complications. Complementary and alternative medicine (CAM), which is gradually becoming more accepted and is believed to be clinically effective, claims to be promising for treating PCOS, and thus its effect on the abnormal endometrium of PCOS patients should be assessed. The present meta-analysis sought to evaluate the efficacy and safety of CAM in treating endometrial lesions in patients with PCOS.

Methods

Randomized trials on CAM were identified in four Chinese and seven English-language databases from their establishment to January 2020. The present study included patients diagnosed with PCOS and abnormal endometrial conditions who underwent CAM therapy independently or in combination with traditional western medicine. Data were extracted, and the Cochrane "risk of bias" tool was used to assess methodological quality. Effects were expressed as the relative risk (RR) or mean difference (MD/SMD) with 95% confidence interval (CI) as calculated with Rev Man 5.3.

Results

A total of 13 randomized controlled trials were included, involving 1,297 PCOS patients treated for endometrial abnormalities. Methodological quality was generally unclear or had a low risk of bias. The trials tested four different types of CAM therapies (i.e., traditional Chinese medicine treatment, acupuncture treatment, traditional Chinese medicine in combination with western medicine treatment, and acupuncture in combination with western medicine treatment). CAM treatment could significantly reduce the endometrial thickness in PCOS patients compared to western medicine alone (SMD -0.88, 95% CI [-0.12, -0.57]; I ² = 64%). Compared with clomiphene treatment for the induction of ovulation, CAM treatment showed a clear improvement in endometrial thickness during ovulation (SMD 2.03, 95% CI [1.64, 2.02]; I ² = 48%). Moreover, CAM was more effective than western medicine alone in reducing the endometrial spiral artery pulsatility index. No significant difference was seen between CAM and traditional treatment when these were used to improve traditional Chinese medicine syndrome scores. Acupuncture alone or traditional Chinese medicines (taken orally) in combination with western medicine significantly increased the pregnancy rate of PCOS patients (RR 1.59, 95% CI [1.30, 1.93]; I ² = 51%, P < 0.00001), and CAM was more effective than western medicine alone for improving hormone levels. No serious adverse events were reported in 11 of the 13 trials.

Conclusions

CAM may effectively ameliorate the endometrial condition of PCOS patients, and it can regulate the level of hormone secretion to increase the ovulation rate and the pregnancy rate.

Steroid hormones and human choriogonadotropin influence the distribution of alpha6-integrin and desmoplakin 1 in gland-like endometrial epithelial spheroids

In human glandular endometrial epithelial cells, desmosomal and adherens junction proteins have been shown to extend from a subapically restricted lateral position to the entire lateral membrane during the implantation window of the menstrual cycle. Similarly, a menstrual cycle stage-dependent redistribution of the extracellular matrix adhesion protein α6-integrin has been reported. These changes are believed to be important for endometrial receptiveness and successful embryo implantation. To prove the hypothesis that steroid hormones and human choriogonadotropin can induce the redistribution of these adhesion molecules, we used the human endometrial cell line Ishikawa in a 3D culture system. Gland-like spheroids were grown in reconstituted basement membrane (Matrigel™). The lumen-bearing spheroids were treated for 2 or 4 days with ovarian steroids or human choriogonadotropin and then assessed by immunofluorescence microscopy. In addition, human endometrial biopsies were obtained from patients, who were in therapy for assisted reproductive technology, and were examined in parallel. Lateral redistribution of the desmosomal plaque protein desmoplakin 1 was observed in the spheroids treated either with progesterone, medroxyprogesterone acetate or human choriogonadotropin. Furthermore, the extracellular matrix adhesion protein α6-integrin showed an increased lateral membrane localization upon gestagen stimulation in the 3D culture system. The results of this study demonstrate that the 3D endometrial Ishikawa cell culture might be suited as an experimental model system to prove the effect of hormonal changes like those occurring during the window of implantation.

Prolonged recombinant pregnancy hormone use in BRCA1 and BRCA2 mutation carriers

BACKGROUND

An early first full-time pregnancy substantially reduces the risk of developing breast cancer later in life. Extensive studies indicate that this protective effect is mediated by the pregnancy hormone human chorionic gonadotrophin (hCG).

METHODS

In this proof-of-concept study 33 women with a BRCA mutation received recombinant-hCG (r-hCG). A 4-mm breast biopsy was obtained before (T1) and after 12 weeks of r-hCG injections (T2), as well as 6 months later (T3). The tissue was examined using RNA-sequencing methodology to determine if the 'high-risk' transcriptomic signature was converted to a 'low-risk' signature as in an early first full-time pregnancy. A stringent clinical safety monitoring was performed.

RESULTS

The r-hCG administration was well tolerated in all participants. No clinically relevant changes were observed. In 25 women, the RNA quality was good for RNA sequencing in all three breast tissue biopsies. In response to the r-hCG, we observed 1907 differentially expressed genes (DEGs) (1032 up, 875 down) at T2 vs. T1 and 1065 DEGs (897 up, 168 down) at T3 vs. T1 in the group of women (n = 11) not using any hormonal contraceptives during the study. There was no response at T2 vs. T1 and a small number of DEGs, 260 (214 up, 46 down) at T3 vs. T1 in the group of 14 women using contraceptives.

CONCLUSIONS

In summary, r-hCG has a remarkable effect on the gene expression profile of breast tissues from BRCA1/2 carriers who did not use any contraception. This opens an opportunity for a novel preventive strategy to reduce the incidence of breast cancer.

Endometriotic cell culture contamination and authenticity: a source of bias in in vitro research?

STUDY QUESTION

Are the primary cell cultures and cell lines used in endometriosis research of sufficient quality?

SUMMARY ANSWER

Primary cells used in endometriosis research lack purity and phenotypic characterisation, and cell lines are not genotypically authenticated.

WHAT IS KNOWN ALREADY

The poor reproducibility of in vitro research and the lack of authenticity of the cell lines used represent reasons of concern in the field of reproductive biology and endometriosis research.

STUDY DESIGN, SIZE, DURATION

In the present study, past in vitro research in the field of endometriosis was systematically reviewed to determine whether the appropriate quality controls were considered. In addition, we explored the performance of Paired Box 2 (Pax2) as an endometrium specific marker in endometrial and endometriotic primary cell cultures; we also characterised the most diffused endometriosis cell lines with respect to important markers including the short tandem repeat (STR) profile.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Literature review part: almost 300 published protocols describing the isolation and creation of primary cell cultures from endometriosis were reviewed. Wet-lab part: primary cells isolated from 13 endometriosis patients were analysed by immunohistochemistry, immunofluorescence and FACS for the expression of Pax2. Cell lines Z11 and Z12, the most diffused endometriosis cell lines, were characterised with respect to the expression of Pax2, steroid hormone receptors and STR profile.

MAIN RESULTS AND THE ROLE OF CHANCE

From the literature review work, we underscored the lack of sufficient cell purity and phenotypic characterisation of primary cell cultures, which present high risk of contaminations from surrounding non-endometriotic tissues. Past work based on the use of cell lines was reviewed as well, and it emerged that cell line authentication was never performed.

In an effort to address these weaknesses for future research, we present data on the performance of Pax2, a suitable marker to exclude ovarian (and other non-endometrial) cell contaminations from primary cell cultures; STR profiles of cell lines Z11 and Z12 were analysed and indicated that the cells were authentic. These profiles are now available for authentication purposes to researchers wishing to perform experiments with these cells.

A quality control pipeline to assure sufficient quality of in vitro research in the field of reproductive biology and endometriosis is proposed. We encourage scientists, research institutes, journal reviewers, editors and funding bodies to raise awareness of the problem and adopt appropriate policies to solve it in the future.

LARGE-SCALE DATA

STR profiles of cell lines Z11 and Z12 are deposited at the Cellosaurus database—web.expasy.org.

LIMITATIONS, REASONS FOR CAUTION

There may be additional markers suitable to assess cell quality.

WIDER IMPLICATIONS OF THE FINDINGS

Future in vitro research in endometriosis and the reliability of outcomes can be improved by using the recommendations presented in this study.

STUDY FUNDING/COMPETING INTEREST(S)

The study was partly financed by the ‘Stichting Fertility Foundation’ (The Netherlands). The authors declare no existing conflict of interest.

TRIAL REGISTRATION NUMBER

Non-applicable.

[Timing of HMG supplementation and clinical outcomes of advanced-age patients with diminished ovarian reserve receiving gonadotropin-releasing hormone antagonist protocol]

OBJECTIVE

To assess the effect and timing of human menopausal gonadotropin (HMG) supplementation in advancedage patients with diminished ovarian reserve (DOR) receiving gonadotropin-releasing hormone antagonist protocol.

OBJECTIVE

A total of 682 patients with DOR aged over 35 years undergoing IVF-ET treatment were included in this study. All the patients underwent a GnRH antagonist protocol, and controlled ovarian stimulation was initiated on day 2-3 of the menstrual cycle with follicle stimulation hormone (FSH). According to the timing of HMG supplementation, the patients were divided into no supplementation group (n=371) without HMG supplementation; early supplementation group (n=139), in which daily HMG supplementation started on the first day till the trigger day; and late supplementation group (n=172), in which HMG supplementation started when the leading follicle reached 10-14 mm in diameter and lasted until the trigger day. The pregnancy outcomes of the patients were compared among the 3 groups.

OBJECTIVE

The 3 groups showed no significant difference in hCG trigger day E2 and P levels, endometrial thickness, or the number of follicles with comparable fertilization rate and cleavage rate (P>0.05). Gn dose used was the lowest in no supplementation group, and the average number of oocytes retrieved was significantly smaller in early supplementation group than in late supplementation group (P < 0.05). The mean number of mature oocytes and embryos available were significantly higher in late supplementation group than in early supplementation group (P < 0.05). The clinical pregnancy rate of fresh embryo transfer cycle was significantly higher in late supplementation group than in no supplementation group (27.7% vs 45.1%, P < 0.05), but the implantation rate, early miscarriage rate, heterotopic pregnancy rate and live birth rate were comparable among the 3 groups (P>0.05). No significant differences were found among the 3 groups in the implantation rate, clinical pregnancy rate, early miscarriage rate, heterotopic pregnancy rate or live birth rate of the first frozen-thawed embryo transfer cycle with a freeze-all strategy (P>0.05).

OBJECTIVE

HMG supplementation in the middle and late follicular phase can improve the outcomes of controlled ovarian hyperstimulation and increase the clinical pregnancy rate of fresh embryo transfer cycle in advanced-age patients with DOR undergoing GnRH antagonist protocol.

Low Serum LH Levels During Ovarian Stimulation With GnRH Antagonist Protocol Decrease the Live Birth Rate After Fresh Embryo Transfers but Have No Impact in Freeze-All Cycles

OBJECTIVE

To explore the association between serum LH levels and the cumulative live birth rate (CLBR) within one complete cycle, and the impact of serum LH levels on the live birth rate (LBR) after the initial embryo transfer (ET) considering different ET strategies (fresh or freeze-all).

DESIGN

A retrospective cohort study.

SETTING

University-affiliated reproductive center.

PATIENTS

1480 normogonadotrophic women who underwent COS with GnRH antagonist protocol for the first IVF/ICSI attempt.

INTERVENTIONS

The sample was stratified into low and higher LH groups according to serum LH peak levels of <4 (Group A) and ≥4 IU/L (Group B) during COS. Patients were also sub-grouped into conventional fresh/frozen ET cycles and freeze-all cycles.

MAIN OUTCOME MEASURES

The LBR after the initial embryo transfer and the CLBR within one complete cycle.

SECONDARY OUTCOME MEASURES

The numbers of day-3 high-quality embryos, the numbers of embryos available, and the other pregnancy outcomes after the initial ET.

RESULTS

In the whole cohort, the CLBRs decreased significantly in the low (63.1% vs. 68.3%, P=.034) LH group compared to the higher LH group. Subgroup analysis revealed that patients with low LH levels had lower LBR after fresh ET (38.0% vs. 51.5%, P=.005) but comparable LBR after the first frozen-thawed ET (FET) in freeze-all cycles (49.8% vs. 51.8%, P=.517) than patients with higher LH peak levels. Likewise, patients with low LH levels had lower CLBR for conventional fresh/frozen ET cycles (54.8% vs. 66.1%, P=.015) but comparable CLBR for the freeze-all cycles (66.8% vs. 69.2%, P=.414) than those with higher LH levels. Following confounder adjustment, multivariable regression analyses showed that low LH level was an independent risk factor for the CLBR in the whole cohort (odds ratio (OR): 0.756, 95% confidence interval (CI): 0.604-0.965, P=.014) and in patients who underwent the conventional ET strategy (OR: 0.596, 95% CI: 0.408-0.917, P=.017). Moreover, the adverse impact of low LH levels on LBRs maintained statistically significant after fresh transfers (OR: 0.532, 95% CI: 0.353-0.800, P=.002) but not after the first FETs in freeze-all cycles (OR: 0.918, 95% CI: 0.711-1.183, P=.508).

CONCLUSIONS

In comparison with higher LH levels, low LH levels decrease the CLBRs per oocyte retrieval cycle for normogonadotrophic women who underwent COS using GnRH antagonists. This discrepancy may arise due to the significant detrimental effect of low LH levels on the LBRs after fresh embryo transfers.

Follicle-Stimulating Hormone Induces Lipid Droplets via Gαi/o and β-Arrestin in an Endometrial Cancer Cell Line

Follicle-stimulating hormone (FSH) and its G protein-coupled receptor, FSHR, represents a paradigm for receptor signaling systems that activate multiple and complex pathways. Classically, FSHR activates Gαs to increase intracellular levels of cAMP, but its ability to activate other G proteins, and β-arrestin-mediated signaling is well documented in many different cell systems. The pleiotropic signal capacity of FSHR offers a mechanism for how FSH drives multiple and dynamic downstream functions in both gonadal and non-gonadal cell types, including distinct diseases, and how signal bias may be achieved at a pharmacological and cell system-specific manner. In this study, we identify an additional mechanism of FSH-mediated signaling and downstream function in the endometrial adenocarcinoma Ishikawa cell line. While FSH did not induce increases in cAMP levels, this hormone potently activated pertussis toxin sensitive Gαi/o signaling. A selective allosteric FSHR ligand, B3, also activated Gαi/o signaling in these cells, supporting a role for receptor-mediated activation despite the low levels of FSHR mRNA. The low expression levels may attribute to the lack of Gαs/cAMP signaling as increasing FSHR expression resulted in FSH-mediated activation of the Gαs pathway. Unlike prior reports for FSH-mediated Gαs/cAMP signaling, FSH-mediated Gαi/o signaling was not affected by inhibition of dynamin-dependent receptor internalization. While chronic FSH did not alter cell viability, FSH was able to increase lipid droplet size. The β-arrestins are key adaptor proteins known to regulate FSHR signaling. Indeed, a rapid, FSH-dependent increase in interactions between β-arrestin1 and Gαi1 was observed via NanoBiT complementation in Ishikawa cells. Furthermore, both inhibition of Gαi/o signaling and siRNA knockdown of β-arrestin 1/2 significantly reduced FSH-induced lipid droplet accumulation, implying a role for a Gαi/o/β-arrestin complex in FSH functions in this cell type. As FSH/FSHR has been implicated in distinct hormone-dependent cancers, including endometrial cancer, analysis of the cancer genome database from 575 human endometrial adenocarcinoma tumors revealed that a subpopulation of samples expressed FSHR. Overall, this study highlights a novel mechanism for FSHR signal pleiotropy that may be exploited for future personalized therapeutic approaches.

In Vitro Study on the Regulation of Annexin IV and VEGF by hCG in the Human Endometrium

Objective

Whether changes in vascular endothelial growth factor (VEGF) and annexin IV during implantation are regulated through the LH/hCG-R needs further research. To investigate the mechanism of hCG on the expression of annexin IV and VEGF in human endometrial cells.

Methods

Endometrial cells were isolated and identified from human specimens. The proportion of glandular and epithelial cells was analyzed. Annexin IV and VEGF were analyzed by qRT-PCR (mRNA), western blot (proteins), and immunohistochemistry (proteins). Protein location was identified by immunohistochemistry. The cells were cultured with hCG, hCG/PD98059 (a MAPK inhibitor), or no treatment (control).

Results

The proportions between the glandular epithelial cells and stromal cells at inoculation and when adding hCG were 25.8 ± 0.2% and 27.8 ± 0.04%, respectively (P > 0.05). LH/hCG-R, annexin IV, and VEGF were found in the cytoplasm of endometrial cells. After 2, 6, 12, and 24 h of hCG treatment, compared with 1 h, VEGF mRNA was increased by 1.25-fold, 3.19-fold, 4.21-fold, and 4.86-fold and annexin IV by 2.23-fold, 3.37-fold, 5.14-fold, and 5.02-fold. Compared with the control group, annexin IV mRNA and protein were increased in the hCG and hCG/PD98059 groups (mRNA/protein: 1.99-fold/1.80-fold and 2.33-fold/1.93-fold, P < 0.05). Compared with the control group, VEGF mRNA and protein were increased in the hCG group (mRNA/protein: 2.30-fold/1.86-fold), but not in the hCG/PD98059 group.

Conclusion

hCG could upregulate the mRNA and protein expression of annexin IV and VEGF. The upregulation of annexin IV by hCG could not be inhibited by PD98059, but the upregulation of VEGF by hCG could.

Follicle-stimulating hormone administration affects amino acid metabolism in mammalian oocytes†

Culture media used in assisted reproduction are commonly supplemented with gonadotropin hormones to support the nuclear and cytoplasmic maturation of in vitro matured oocytes. However, the effect of gonadotropins on protein synthesis in oocytes is yet to be fully understood. As published data have previously documented a positive in vitro effect of follicle-stimulating hormone (FSH) on cytoplasmic maturation, we exposed mouse denuded oocytes to FSH in order to evaluate the changes in global protein synthesis. We found that dose-dependent administration of FSH resulted in a decrease of methionine incorporation into de novo synthesized proteins in denuded mouse oocytes and oocytes cultured in cumulus-oocyte complexes. Similarly, FSH influenced methionine incorporation in additional mammalian species including human. Furthermore, we showed the expression of FSH-receptor protein in oocytes. We found that major translational regulators were not affected by FSH treatment; however, the amino acid uptake became impaired. We propose that the effect of FSH treatment on amino acid uptake is influenced by FSH receptor with the effect on oocyte metabolism and physiology.

Corifollitropin alfa for poor responders patients, a prospective randomized study

BACKGROUND

Poor ovarian response remains one of the biggest challenges for reproductive endocrinologists. The introduction of corifollitropin alpha (CFA) offered an alternative option to other gonadotropins for its longer half-life, its more rapid achievement of the threshold and higher FSH levels. We compared two different protocols with CFA, a long agonist and a short antagonist, and a no-CFA protocol.

METHODS

Patients enrolled fulfilled at least two of the followings: AFC < 5, AMH < 1,1 ng/ml, less than three oocytes in a previous cycle, age > 40 years. Ovarian stimulation with an antagonist protocol was performed either with 300 UI rFSH and 150 UI rLH or 300UI HMG. In the long agonist group, after pituitary suppression with triptorelin, CFA was given the 1-2th day of cycle and 300 UI rFSH and 150 UI rLH the 5th day. In the short antagonist group CFA was given the 1-2th day of cycle and 300 UI rFSH and 150 UI rLH the 5th day. The primary objective was the effect on the number of oocytes and MII oocytes. Secondary objective were pregnancy rates, ongoing pregnancies and ongoing pregnancies per intention to treat.

RESULTS

The use of CFA resulted in a shorter lenght of stimulation and a lower number of suspended treatments. Both the CFA protocols were significantly different from the no-CFA group in the number of retrieved oocytes (p < 0,05), with a non-significant difference in favour of the long agonist protocol. Both CFA groups yielded higher pregnancy rates, especially the long protocol, due to the higher number of oocytes retrieved (p < 0,05), as implantation rates did not differ. The cumulative pregnancy rate was also different, due to the higher number of cryopreserved blastocysts (p < 0,02).

CONCLUSIONS

The long agonist protocol with the addition of rFSH and rLH showed the best results in all the parameters. A short antagonist protocol with CFA was less effective, but not significantly, although provided better results compared to the no-CFA group. We suggest that a long agonist protocol with CFA and recombinant gonadotropins might be a valuable option for poor responders.

TRIAL REGISTRATION

The study was approved by the local Ethics Committee (EudraCT2015-002817-31).

The effect of a transient premature luteinizing hormone surge without elevated serum progesterone on in vitro fertilization outcomes in a gonadotropin-releasing hormone antagonist flexible protocol

During controlled ovarian stimulation, the LH rising before triggering can lead to follicular luteinizations. However, LH can be suppressed immediately and no progesterone elevation with GnRH antagonist. This study retrospectively compared fresh IVF/ICSI cycle outcomes in antagonist protocols between the group with and the group without a premature LH surge. Logistic regression models were fitted to reduce the relevant confounders. Compared between premature LH surge group and control group, the implantation rates were 12.9% (30/233) vs 25.0% (141/536), p = .000; clinical pregnancy rates were 21.0% (25/119) vs 41.6% (119/286), p = .000; live birth rates were17.6% (21/119) vs 29.7% (85/286), p = .012. After adjusting for age, BMI, bFSH, and infertility factors, the adverse effects were still as pronounced for the clinical pregnancy rate (OR = 0.39, 95% CI = 0.24-0.66) and live birth rates (OR = 0.54, 95% CI = 0.32-0.93. In a GnRH antagonist flexible protocol, a transient premature LH surge which can be suppressed immediately after the initiation of antagonist without elevated serum progesterone, will cause a detrimental effect on the development of the embryo and IVF/ICSI pregnancy outcomes in fresh embryo transfer cycles.

Gonadotrophins modulate cell death-related genes expression in human endometrium

Background Gonadotrophins exert their functions by binding follicle-stimulating hormone receptor (FSHR) or luteinizing hormone and human chorionic gonadotropin receptor (LHCGR) present on endometrium. Within ovaries, FSH induces autophagy and apoptosis of granulosa cells leading to atresia of non-growing follicles, whereas hCG and LH have anti-apoptotic functions. Endometrial cells express functioning gonadotrophin receptors. The objective of this study was to analyze the effect of gonadotrophins on physiology and endometrial cells survival. Materials and methods Collected endometria were incubated for 48 or 72 h with 100 ng/mL of recombinant human FSH (rhFSH), recombinant human LH (rhLH) or highly purified hCG (HPhCG) alone or combined. Controls omitted gonadotrophins. The effect of gonadotrophins on cytochrome P450 family 11 subfamily A polypeptide 1 (CYP11A1), hypoxia inducible factor 1α (HIF1A), and cell-death-related genes expression was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Immunohistochemistry for microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B) and apoptotic protease activating factor 1 (APAF-1) was performed. Results Gonadotrophins are able to modulate the endometrial cells survival. FSH induced autophagy and apoptosis by increasing the relative expression of MAP1LC3B and FAS receptor. In FSH-treated samples, expression of apoptosis marker APAF-1 was detected and co-localized on autophagic cells. hCG and LH does not modulate the expression of cell-death-related genes while the up-regulation of pro-proliferative epiregulin gene was observed. When combined with FSH, hCG and LH prevent autophagy and apoptosis FSH-induced. Conclusions Different gonadotrophins specifically affect endometrial cells viability differently: FSH promotes autophagy and apoptosis while LH and hCG alone or combined with rhFSH does not.

Cloning and expression analysis of the follicle-stimulating hormone receptor (FSHR) gene in the reproductive axis of female yaks (Bos grunniens)

Follicle-stimulating hormone receptor (FSHR) plays a central role in promoting follicle maturation through the follicle-stimulating hormone (FSH)-mediated cAMP pathway in animals. The objectives of the present study were to clone the FSHR gene of yaks (Bos grunniens) and compare differences in FSHR mRNA expression in the reproductive axis between yaks and cattle. Hypothalamus, anterior pituitary, oviduct, ovary, and uterus tissue samples were collected from adult female yaks (n = 5) and cattle (n = 5) during the follicular phase. Using reverse transcriptase-polymerase chain reaction (RT-PCR), we found that the FSHR coding region of the yak is 2088 bp and encodes 695 amino acids. Its amino acid sequence showed 99.38%-72.22% similarity to the homologous genes of cattle, goats, sheep, cats, donkeys, horses, humans, chickens, monkeys, mice, rats, and wild boar. Real-time PCR analysis revealed that the FSHR gene was expressed in all tissues examined. Expression of the FSHR gene in the yak was higher in the uterus than other tissues (P < 0.05) but, in cattle, was higher in the ovary than other tissues (P < 0.05). The FSHR gene expression level in the cattle ovary was significantly higher than that in the yak ovary (P < 0.01). These results indicate that the FSHR gene is relatively conserved in the course of animal evolution. The variation in sequence and expression level of FSHR between the two species might be associated with the difference in their reproduction.

Intrauterine injection of human chorionic gonadotropin before embryo transfer can improve in vitro fertilization-embryo transfer outcomes: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate whether intrauterine injection of hCG before embryo transfer can improve IVF-ET outcomes.

DESIGN

Meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Infertile women who underwent IVF-ET and received an intrauterine injection of hCG before ET.

INTERVENTION(S)

Infertile women treated with or without intrauterine hCG injection before ET.

MAIN OUTCOME MEASURE(S)

The primary outcomes were live birth rate (LBR), ongoing pregnancy rate (OPR), and clinical pregnancy rate (CPR), and the secondary outcomes were implantation rate (IR) and miscarriage rate (MR). Odds ratios with 95% confidence intervals (CIs) and successful ET rates were pooled to determine the effects of hCG on IVF-ET outcomes.

RESULT(S)

Fifteen randomized controlled trials (RCTs) with a total of 2,763 participants were included. Infertile women in the experimental group (treated with intrauterine hCG injection before ET) exhibited significantly higher LBR (44.89% vs. 29.76%), OPR (48.09% vs. 33.42%), CPR (47.80% vs. 32.78%), and IR (31.64% vs. 22.52%) than those in the control group (intrauterine injection of placebo or no injection). Furthermore, MR was significantly lower (12.45% vs. 18.56%) in the experimental group than in the control group.

CONCLUSION(S)

The findings of this meta-analysis indicate that intrauterine injection of hCG can improve LBR, OPR, CPR, and IR after IVF-ET cycles. In addition, different timing and dosages of hCG administration may exert different effects on IVT-ET outcomes. Notably, infertile women treated with 500 IU hCG within 15 minutes before ET can achieve optimal IVF-ET outcomes.

Receptor Binding Inhibitor Suppresses Carcinogenesis of Cervical Cancer by Depressing Levels of FSHR and ERβ in Mice

BACKGROUND

FSH Receptor Binding Inhibitor (FRBI) blocked the binding of FSH to FSHR. Our initial study revealed FRBI reduced the maturation rate, enhanced the apoptosis of sheep Cumulus-Oocyte Complex (COCs). Little is known about whether FRBI modulates ERβ and FSHR levels in the normal uterine and cancerous tissues. The present study aimed to evaluate the FRBI effects on the expressions of Estrogen Receptor-beta (ERβ) and FSH receptor (FSHR) in the uteri.

METHODS

150 mice were assigned to FRBI+FSH (COM), FSH and control groups (CG). Mice of COM-1, COM-2 and COM-3 groups were simultaneously intramuscularly injected with 500, 750 and 1000 µg FRBI with 10 IU FSH, respectively for five days. Western blotting and qPCR were utilized to determine the expression of ERβ and FSHR.

RESULTS

In comparison with FSH group, uterine lumen and glands of COM groups became narrow. The uterine wall and endometrial epithelium were thinned, and uterine lumen became narrow. Epithelial cells were decreased. Uterine wall thicknesses of COM-1, COM-2 and COM-3 groups were reduced by 6.49%, 14.89% and 15.69% on day 30 as compared with FSH group. Uterine perimetrium thicknesses of COM-1, COM-2 and COM-3 groups were reduced by 16.17%, 17.93% and 19.92% on day 20 in comparison with FSH group. Levels of FSHR mRNAs and proteins of COM-1, COM-2 and COM-3 groups were less than FSH group on days 20 and 30 (P<0.05). ERβ protein of COM-3 group was less than FSH group. Serum estradiol (E2) and FSH concentrations of COM-2 and COM-3 were lower than that of FSH group on day 30.

CONCLUSION

FRBI could decrease UWT and UPT, also block the uterine development, decline expression levels of ERβ and FSHR protein. Additionally, FRBI reduced the secretion of secretion of FSH and E2. Downregulating expression of FSHR and ERβ may be a potential treatment regimen for cervical cancer patients.

Effect of intrauterine injection of human chorionic gonadotropin before frozen-thawed embryo transfer on pregnancy outcomes in women with endometriosis

Objective

To investigate the effect of human chorionic gonadotropin (hCG) intrauterine injection before frozen–thawed embryo transfer (FET) in women with endometriosis.

Methods

This retrospective cohort study included 45 women with endometriosis who underwent hCG intrauterine injection before FET; each woman was matched with three patients with endometriosis who did not receive hCG intrauterine injection (controls). Data on pregnancy and prenatal outcomes were extracted from medical records and compared.

Results

Patients in the hCG intrauterine injection group had significantly higher rates of pregnancy and clinical pregnancy (64.4% and 57.8%, respectively) than controls (47.4% and 39.3%, respectively). Neonatal birth weight for both singletons and twins was significantly higher in the hCG group (3486 ± 458 g and 2710 ± 437 g, respectively) than in the control group (3195 ± 401 g and 2419 ± 370 g, respectively).

Conclusion

Pregnancy rate, clinical pregnancy rate, and birth weight were improved in women with endometriosis who underwent intrauterine hCG injection compared with those who did not receive hCG before FET.

Proliferation Profile of Uterine Endometrial Stromal Cells during In Vitro Culture with Gonadotropins: Recombinant versus Urinary Follicle Stimulating Hormone

BACKGROUND

Provision of optimal endometrial stromal cells is essential in uterine tissue engineering. Culture of these cells is significantly influenced by gonadotropin hormones. This investigation attempted to define the proliferation profiles of murine uterine endometrial stromal cells during in vitro culture with recombinant follicle stimulating hormone (rFSH), urinary follicle stimulating hormone (uFSH), and human chorionic gonadotropin (hCG).

METHODS

Murine uterine endometrial stromal cells were collected from 8-week-old mice and cultured in vitro up to 72 h, with rFSH, uFSH, or hCG. Cell cycles were analyzed by BrdU assay, and cyclin D1 expression was evaluated according to dose and duration of gonadotropin treatment.

RESULTS

BrdU assay showed a further inhibitory effect on murine uterine endometrial stromal cell proliferation when cultured with rFSH compared to uFSH, and a similar inhibitory proliferation profile when cultured with hCG at a specific range of concentrations. The expression of cyclin D1 of murine uterine endometrial stromal cells was down-regulated when cultured with rFSH, uFSH, or hCG, compared to control.

CONCLUSIONS

FSH may inhibit the proliferation of murine uterine endometrial stromal cells during in vitro culture. rFSH may have more significant inhibitory effects on the proliferation of endometrial stromal cells than uFSH. Establishing an optimal endocrine milieu is necessary using more advanced combination of female hormones for in vitro culture of this type of cells.

Extragonadal FSHR Expression and Function-Is It Real?

Expression of the follicle-stimulating hormone receptor (FSHR), besides gonadal tissues, has recently been detected in several extragonadal normal and tumorous tissues, including different types of primary and metastatic cancer and tumor vessel endothelial cells (TVEC). The suggested FSH actions in extragonadal tissues include promotion of angiogenesis, myometrial contractility, skeletal integrity, and adipose tissue accumulation. Non-malignant cells within cancer tissue have been shown to be devoid of FSHR expression, which implies a potential role of FSHR as a diagnostic, prognostic, or even a therapeutic tool. There are shared issues between several of the published reports questioning the validity of some of the conclusion. Firstly, protein expression of FSHR was performed solely with immunohistochemistry (IHC) using either an unavailable "in house" FSHR323 monoclonal antibody or poorly validated polyclonal antibodies, usually without additional methodological quality control and confirmations. Secondly, there is discrepancy between the hardly traceable or absent FSHR gene amplification/transcript data and non-reciprocal strong FSHR protein immunoreactivity. Thirdly, the pharmacological high doses of recombinant FSH used in in vitro studies also jeopardizes the physiological or pathophysiological meaning of the findings. We performed in this review a critical analysis of the results presenting extragonadal expression of FSHR and FSH action, and provide a rationale for the validation of the reported results using additional more accurate and sensitive supplemental methods, including in vivo models and proper positive and negative controls.

Pharmacogenetics of FSH Action in the Female

The purpose of a pharmacogenomic approach is to tailor treatment on the basis of an individual human genotype. This strategy is becoming increasingly common in medicine, and important results have been obtained in oncologic and antimicrobial therapies. The rapid technological developments and availability of innovative methodologies have revealed the existence of numerous genotypes that can influence the action of medications and give rise to the idea that a true "individualized" approach could become in the future a reality in clinical practice. Moreover, compared to the past, genotype analyses are now more easily available at accessible cost. Concerning human reproduction, there is ample evidence that several variants of gonadotropins and their receptors influence female reproductive health and ovarian response to exogenous gonadotropins. In more detail, variants in genes of follicle-stimulating hormone β-chain (FSH-B) and its receptor (FSH-R) seem to be the most promising candidates for a pharmacogenomic approach to controlled ovarian stimulation in assisted reproductive technologies. In the present review, we summarize the evidence regarding FSH-B and FSH-R variants, with special reference to their impact on reproductive health and assisted reproductive technology treatments.

FSH Actions and Pregnancy: Looking Beyond Ovarian FSH Receptors

By mediating estrogen synthesis and follicular growth in response to FSH, the ovarian FSH receptor (FSHR) is essential for female fertility. Indeed, ovarian stimulation via administration of FSH to women with infertility is part of the primary therapeutic intervention used in assisted reproductive technology. In physiological and therapeutic contexts, current dogma dictates that once ovulation has occurred, FSH/FSHR signaling is no longer required for successful pregnancy outcomes. However, a continued role for FSH during pregnancy is suggested by recent studies demonstrating extraovarian FSHR in the female reproductive tract. Furthermore, functional roles for FSHR in placenta and in uterine myometrium have now been demonstrated. In placenta, vascular endothelial FSHR of fetal vessels within the chorionic villi (human) or labyrinth (mouse) mediate angiogenesis, and it has further been shown that deletion of placental Fshr in mice has deleterious effects on pregnancy. In uterine myometrium, changes in the densities of FSHR in muscle fiber and stroma in the nonpregnant state, early pregnancy, and term pregnancy differentially regulate contractile activity, suggesting that signaling through myometrial FSHR may contribute to the quieting of contractile activity required for successful implantation and that the temporal upregulation of the FSHR at term pregnancy may be required for the appropriate timing of parturition. In addition, extraovarian expression of mRNAs encoding the glycoprotein hormone α subunit and the FSH β subunit has been demonstrated, suggesting that these novel aspects of extraovarian FSH/FSHR signaling during pregnancy may be mediated by locally synthesized FSH.