Role and effectiveness of progestins in pituitary suppression during ovarian stimulation for assisted reproductive technology: a systematic review and a meta-analysis

INTRODUCTION

Despite the many unknowns about its exact mechanism, progesterone and progestins are being successfully used to prevent luteinizing hormone (LH) surge during ovarian stimulation for assisted reproductive technology (ART). We will review progestin primed ovarian stimulation (PPOS) protocols in comparison with gonadotropin releasing hormone (GnRH) analogues and each other.

EVIDENCE ACQUISITION

MEDLINE via PubMed; Cochrane Central Register of Controlled Trials (CENTRAL); Scopus; Web of Science were screened with keywords related to assisted reproductive technology, ovarian stimulation progesterone, GnRH analogue and progesterone in several combinations. Search period was from the date of inception of each database until 20 May 2022.

EVIDENCE SYNTHESIS

Live birth or ongoing pregnancy rate per embryo transfer (ET) was similar in PPOS and GnRH antagonist cycles (RR=1.16, 95% CI: 0.93-1.44). Clinical pregnancy rate per ET was likewise similar (RR=1.12, 95% CI: 0.92-1.37). Miscarriage rate per pregnancy was similar with PPOS and GnRH antagonists in autologous cycles (RR=1.01, 95% CI: 0.65-1.55). Pooled analyses showed similar live birth rate between progestins and short GnRH agonist protocols (RR=1.01, 95% CI: 0.49-2.09), however, clinical pregnancy rates per ET were significantly higher with progestins (RR=1.31, 95% CI: 1.06-1.62). Miscarriage rate per pregnancy was similar with progestins (RR=0.82, 95% CI: 0.55-1.21).

CONCLUSIONS

Progestins seem to be an efficient option for pituitary suppression during ovarian suppression, providing similar outcomes for stimulation and pregnancy. They can be especially beneficial for women for whom fresh ET is not considered.

Progesterone signaling in the regulation of luteal steroidogenesis

The corpus luteum is the major source of progesterone, the essential hormone for female reproductive function. While progesterone activity has been the subject of extensive research for decades, characterization of non-canonical progesterone receptor/signaling pathways provided a new perspective for understanding the complex signal transduction mechanisms exploited by the progesterone hormone. Deciphering these mechanisms has significant implications in the management of luteal phase disorders and early pregnancy complications. The purpose of this review is to highlight the complex mechanisms through which progesterone-induced signaling mediates luteal granulosa cell activity in the corpus luteum. Here, we review the literature and discuss the up-to-date evidence on how paracrine and autocrine effects of progesterone regulate luteal steroidogenic activity. We also review the limitations of the published data and highlight future research priorities.

Male minipuberty involves the gonad-independent activation of preoptic nNOS neurons

BACKGROUND

The maturation of the hypothalamic-pituitary-gonadal (HPG) axis is crucial for the establishment of reproductive function. In female mice, neuronal nitric oxide synthase (nNOS) activity appears to be key for the first postnatal activation of the neural network promoting the release of gonadotropin-releasing hormone (GnRH), i.e. minipuberty. However, in males, the profile of minipuberty as well as the role of nNOS-expressing neurons remain unexplored.

METHODS

nNOS-deficient and wild-type mice were studied during postnatal development. The expression of androgen (AR) and estrogen receptor alpha (ERα) as well as nNOS phosphorylation were evaluated by immunohistochemistry in nNOS neurons in the median preoptic nucleus (MePO), where most GnRH neuronal cell bodies reside, and the hormonal profile of nNOS-deficient male mice was assessed using previously established radioimmunoassay and ELISA methods. Gonadectomy and pharmacological manipulation of ERα were used to elucidate the mechanism of minipubertal nNOS activation and the maturation of the HPG axis.

RESULTS

In male mice, minipubertal FSH release occurred at P23, preceding the LH surge at P30, when balanopreputial separation occurs. Progesterone and testosterone remained low during minipuberty, increasing around puberty, whereas estrogen levels were high throughout postnatal development. nNOS neurons showed a sharp increase in Ser¹⁴¹² phosphorylation of nNOS at P23, a phenomenon that occurred even in the absence of the gonads. In male mice, nNOS neurons did not appear to express AR, but abundantly expressed ERα throughout postnatal development. Selective pharmacological blockade of ERα during the infantile period blunted Ser¹⁴¹² phosphorylation of nNOS at P23.

CONCLUSIONS

Our results show that the timing of minipuberty differs in male mice when compared to females, but as in the latter, nNOS activity in the preoptic region plays a role in this process. Additionally, akin to male non-human primates, the profile of minipuberty in male mice is shaped by sex-independent mechanisms, and possibly involves extragonadal estrogen sources.

Postnatal developmental trajectory of sex-biased gene expression in the mouse pituitary gland

BACKGROUND

The pituitary gland regulates essential physiological processes such as growth, pubertal onset, stress response, metabolism, reproduction, and lactation. While sex biases in these functions and hormone production have been described, the underlying identity, temporal deployment, and cell-type specificity of sex-biased pituitary gene regulatory networks are not fully understood.

METHODS

To capture sex differences in pituitary gene regulation dynamics during postnatal development, we performed 3' untranslated region sequencing and small RNA sequencing to ascertain gene and microRNA expression, respectively, across five postnatal ages (postnatal days 12, 22, 27, 32, 37) that span the pubertal transition in female and male C57BL/6J mouse pituitaries (n = 5-6 biological replicates for each sex at each age).

RESULTS

We observed over 900 instances of sex-biased gene expression and 17 sex-biased microRNAs, with the majority of sex differences occurring with puberty. Using miRNA-gene target interaction databases, we identified 18 sex-biased genes that were putative targets of 5 sex-biased microRNAs. In addition, by combining our bulk RNA-seq with publicly available male and female mouse pituitary single-nuclei RNA-seq data, we obtained evidence that cell-type proportion sex differences exist prior to puberty and persist post-puberty for three major hormone-producing cell types: somatotropes, lactotropes, and gonadotropes. Finally, we identified sex-biased genes in these three pituitary cell types after accounting for cell-type proportion differences between sexes.

CONCLUSION

Our study reveals the identity and postnatal developmental trajectory of sex-biased gene expression in the mouse pituitary. This work also highlights the importance of considering sex biases in cell-type composition when understanding sex differences in the processes regulated by the pituitary gland.

Genetic variation in progesterone receptor gene and ovarian cancer risk: A case control study

BACKGROUND

Previous studies examined the association of genetic variation in progesterone receptor (PR) gene (PGR) with ovarian cancer, possibly by altering the expression of PR-B isoform, but with mixed outcome.

OBJECTIVE

This study evaluated the association of PGR variants with ovarian cancer and associated features.

METHODS

This was a retrospective case-control study, which involved 82 women with ovarian cancer and 95 cancer-free women who served as controls. Genotyping was done by Taqman® SNP genotyping by qRT-PCR. The PGR variants tested were rs471767 (A > G), rs590688 (G > C), and rs10895068 (G > A). Stratification analyses were used for testing the correlation between the PGR variants with ovarian cancer susceptibility according to menstruation status, FIGO classification, pathological grade, and chemotherapy.

RESULTS

Significantly lower minor allele frequency (MAF) of rs10895068 was seen among ovarian cancer patients, thereby imparting disease protective nature to this variant. Significant association of rs10895068 genotypes with ovarian cancer was seen under the dominant model, but not other genetic models. FIGO classification correlated positively with rs471767 and rs10895068, while rs10895068 correlated positively with lymph node positivity. Three-locus haplotype analysis identified ACA and HCG haplotypes to be negatively associated with the risk of ovarian cancer.

CONCLUSIONS

This report confirms the contribution of PGR variants, specifically the rs10895068 (+331G/A) the etiology of ovarian cancer.

Evaluation of Expression and Phosphorylation of Progesterone Receptor in Endometrial Stromal Cells of Patients with Recurrent Implantation Failure Compared to Healthy Fertile Women

Recurrent implantation failure (RIF) is the repeated failure of good-quality embryos in implantation process following several assisted reproduction cycles. Disruption of the endometrial receptivity is one of the main causes of RIF. Progesterone plays a pivotal role in the endometrial receptivity through the regulation of gene expression pattern by binding to its receptors in the endometrial cells. The aim of this study was to evaluate the expression level of progesterone receptor (PR) and its phosphorylated form in the endometrial stromal cells (eSC) of RIF patients and compare it to the eSC of healthy fertile women as control group. After isolation of the eSC from biopsy samples of RIF patients and healthy fertile women and their characterization, expression levels of PR mRNA, PR protein, and phospho-Ser294 PR protein were evaluated by quantitative real-time PCR and immunofluorescence staining, respectively. The results demonstrated a significant reduction in PR mRNA expression (P < 0.01.) and phospho-Ser294 PR protein (P < 0.05) level in RIF patients compared to the control group. These data for the first time suggest that the expression of PR and its phosphorylated form are impaired in RIF patients. Therefore, designing therapeutic methods for improving PR expression status and its regulation in the endometrium of RIF patients may help in improving the final reproductive outcomes of these cases.

Progestins for pituitary suppression during ovarian stimulation for ART: a comprehensive and systematic review including meta-analyses

BACKGROUND

Progestins are capable of suppressing endogenous LH secretion from the pituitary. Progestins can be used orally and are less expensive than GnRH analogues. However, early endometrial exposure to progestin precludes a fresh embryo transfer (ET), but the advent of vitrification and increasing number of oocyte cryopreservation cycles allow more opportunities for using progestins for pituitary suppression.

OBJECTIVE AND RATIONALE

This review summarizes: the mechanism of pituitary suppression by progestins; the effectiveness of progestins when compared with GnRH analogues and with each other; the effect of progestins on oocyte and embryo developmental potential and euploidy status; and the cost-effectiveness aspects of progestin primed stimulation. Future research priorities are also identified.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, the Web of Science and Scopus were screened with a combination of keywords related to ART, progesterone, GnRH analogue and ovarian stimulation, in various combinations. The search period was from the date of inception of each database until 1 April 2020. Only full text papers published in English were included.

OUTCOMES

Overall, the duration of stimulation, gonadotrophin consumption and oocyte yield were similar with progestins and GnRH analogues. However, sensitivity analyses suggested that progestins were associated with significantly lower gonadotrophin consumption than the long GnRH agonist protocol (mean difference (MD) = -648, 95% CI = -746 to -550 IU) and significantly higher gonadotrophin consumption than the short GnRH agonist protocol (MD = 433, 95% CI = 311 to 555 IU). Overall, live birth, ongoing and clinical pregnancy rates per ET were similar with progestins and GnRH analogues. However, when progestins were compared with GnRH agonists, sensitivity analyses including women with polycystic ovary syndrome (risk ratio (RR) = 1.27, 95% CI = 1.06 to 1.53) and short GnRH agonist protocols (RR = 1.14, 95% CI = 1.02 to 1.28) showed significantly higher clinical pregnancy rates with progestins. However, the quality of evidence is low. Studies comparing medroxyprogesterone acetate, dydrogesterone and micronized progesterone suggested similar ovarian response and pregnancy outcomes. The euploidy status of embryos from progestin primed cycles was similar to that of embryos from conventional stimulation cycles. Available information is reassuring regarding obstetric and neonatal outcomes with the use of progestins. Despite the lower cost of progestins than GnRH analogues, the mandatory cryopreservation of all embryos followed by a deferred transfer may increase cost per live birth with progestins as compared to an ART cycle culminating in a fresh ET.

WIDER IMPLICATIONS

Progestins can present an effective option for women who do not contemplate a fresh ET, e.g. fertility preservation, anticipated hyper responders, preimplantation genetic testing, oocyte donors, double stimulation cycles.

Systemic distribution of progesterone receptor subtypes in human tissues

Progesterone receptor (PR) is expressed in a wide variety of human tissues, including both reproductive and non-reproductive tissues. Upon binding to the PR, progesterone can display several non-reproductive functions, including neurosteroid activity in the central nervous system, inhibition of smooth muscle contractile activity in the gastrointestinal tract, and regulating the development and maturation of the lung. PR exists as two major isoforms, PRA and PRB. Differential expression of these PR isoforms reportedly contributes to different biological activities of the hormone. However, the distribution of the PR isoforms in human tissues has remained virtually unexplored. In this study, we immunolocalized PR expression in various human tissues using PR (1294) specific antibody, which is capable of detecting both PRA and PRB, and PRB (250H11) specific antibody. Tissues from the uterus, ovary, breast, placenta, prostate, testis, cerebrum, cerebellum, pituitary, spinal cord, esophagus, stomach, small intestine, colon, pancreas, liver, kidney, urinary bladder, lung, heart, aorta, thymus, adrenal gland, thyroid, spleen, skin, and bone were examined in four different age groups (fetal, pediatric, young, and old) in male and female subjects. PR and PRB were detected in the nuclei of cells in the female reproductive system, in both the nuclei and cytoplasm of pituitary gland and pancreatic acinar cells, and only in the cytoplasm of cells in the testis, stomach, small intestine, colon, liver, kidney, urinary bladder, lung, adrenal gland, and skin. Of particular interest, total PRB expression overlapped with that of total PR expression in most tissues but was negative in the female fetal reproductive system. The findings indicate that progesterone could affect diverse human organs differently than from reproductive organs. These findings provide new insights into the novel biological roles of progesterone in non-reproductive organs.

Efficacy of Different Progestins in Women With Advanced Endometriosis Undergoing Controlled Ovarian Hyperstimulation for in vitro Fertilization-A Single-Center Non-inferiority Randomized Controlled Trial

Object: Is it possible to use different progestins cotreatment with human menopausal gonadotrophin (hMG) in women with advanced endometriosis but normal ovulation during controlled ovarian hyperstimulation (COH) in vitro fertilization (IVF)? Whether different progestins treatments can be an alternative choice for women with severe endometriosis in considering IVF/ICSI treatment remains unknown? Design: Non-inferiority randomized clinical trial. Setting: Tertiary-care academic medical center. Population: Four hundred and fifty infertile patients with severe endometriosis undergoing IVF/ICSI between May 2016 and March 2017. Methods: Four hundred and fifty infertile patients with severe endometriosis undergoing IVF/ICSI were randomized to: medroxyprogesterone acetate +hMG; dydrogesterone +hMG; and progesterone +hMG. Ovulation was induced with a gonadotropin-releasing hormone agonist (GnRH-a) and chorionic gonadotropin (hCG). Viable embryos were cryopreserved for later transfer. Main Outcome Measures: The primary endpoint outcome was the number of oocytes retrieved. Secondary indicators included the incidence of a premature surge in luteinizing hormone (LH), the number of viable embryos, and clinical pregnancy outcomes. Results: The number of oocytes retrieved was higher in the medroxyprogesterone acetate +hMG group than the two other groups (9.3 ± 5.7 vs. 8.0 ± 4.5 vs. 7.8 ± 5.2, P = 0.021). LH levels were suppressed after a 6-day progestin treatment in the medroxyprogesterone acetate +hMG and dydrogesterone +hMG groups, but there was a rebound of LH values in the progesterone +hMG group. No premature LH surge and ovarian hyperstimulation syndrome (OHSS) occurred. No significant differences among the three groups were observed in fertilization and pregnancy outcomes. Conclusion: It is mandatory to point out that our conclusions are valid for patients with ovarian advanced endometriosis but normal ovarian functions. These results suggest three different progestins protocols are equivalent in terms of pregnancy outcomes for women with advanced endometriosis. PPOS protocol can be an alternative choice for women with severe endometriosis and normal ovarian reserve in IVF/ICSI treatment. These methods could be tested with other populations of women with endometriosis. Clinical Trial Registration: www.ClinicalTrials.gov, identifier:ChiCTR-OIN-16008529. Trial registration date: 2014-05-25. Date of first patient enrollment: May 2016.

Use of medroxyprogesterone acetate in women with ovarian endometriosis undergoing controlled ovarian hyperstimulation for in vitro fertilization

This study investigated the use of medroxyprogesterone acetate (MPA) or a short protocol for controlled ovarian hyperstimulation (COH) in patients with advanced endometriosis who have normal ovarian function, and to compare cycle characteristics and pregnancy outcomes after frozen-thawed embryo transfer (FET). This was a retrospective case-control study of 244 patients with advanced endometriosis undering COH. The patients were allocated to three groups: the surgery group with MPA COH (62 patients, 71 IVF/ICSI cycles, 78 FET cycles); the aspiration group with MPA COH (85 patients had ovarian “chocolate” cysts (>3 cm) aspirated, 90 IVF/ICSI cycles, 76 FET cycles); and the short protocol group (97 patients, 101 IVF/ICSI cycles, 51 FET cycles). The results showed that higher rates of mature oocyte, D3 high quality embryo, hMG dose were observed in the two study groups using MPA compared with the short protocol. The number of >10–14 mm follicles on the trigger day, D3 top-quality embryos, viable embryos, rates of cancellation, fertilization, implantation, pregnancy outcomes were similar among the three groups. The oocytes, embryos, and pregnancy outcomes were not influenced by endometrioma surgery or presence of endometrioma. MPA COH could be effective for women with ovarian advanced endometriosis who had normal ovarian function.