Effect of clomiphene citrate on endometrial thickness, ovulation, pregnancy and live birth in anovulatory women: systematic review and meta-analysis

Zingiberis rhizoma-based carbon dots alter serum oestradiol and follicle-stimulating hormone levels in female mice

Chinese herbs contain substances that regulate female hormones. Our study confirmed that Zingiberis rhizoma carbonisata contains Zingiberis rhizoma-based carbon dots (ZR-CDs), which exert regulatory effects on serum oestradiol and FSH in mice and show impacts on endometrial growth and follicular development that potentially affect the ability of female fertility. ZR-CDs were characterized to clarify the microstructure, optical features, and functional group characteristics. It shows that ZR-CDs are spherical carbon nanostructures ranging from 0.97 to 2.3 nm in diameter, with fluorescent properties and a surface rich in functional groups. We further investigated the impact of ZR-CDs on oestradiol and FSH in serum, growth, and the development of ovarian and uterine using normal female mice and exogenous oestradiol intervention model. It was observed that ZR-CDs accelerated oestrogen metabolism and attenuated oestradiol-induced endometrial hyperplasia. Simultaneously, ZR-CDs triggered an increase in FSH, even in the presence of high-serum oestradiol that inhibits FSH secretion. Our findings suggest that ZR-CDs could be a potential therapeutic treatment for anovulatory menstruation.

The impact of estradiol supplementation on endometrial thickness and intrauterine insemination outcomes

The impact of estrogen supplementation during the follicular/proliferative phase on the endometrial lining thickness (EMT) prior to intrauterine insemination (IUI) remains largely unstudied. Our study examined changes in EMT and rates of clinical pregnancy, miscarriage, and live birth for all patients who completed an IUI cycle at Stanford Fertility Center from 2017-2023 (n = 2281 cycles). Cycles with estradiol supplementation (n = 309) were compared to reference cycles without supplementation (n = 1972), with the reference cohort further categorized into cycles with a pre-ovulatory EMT of < 7 mm ("thin-lining", n = 536) and ≥ 7 mm ("normal-lining", n = 1436). The estradiol group had a statistically significant greater change in EMT from baseline to ovulation compared to the thin-lining reference groups (2.4 mm vs 1.9 mm, p < =0.0001). Similar rates of clinical pregnancy and live birth were observed. After adjusting for age, BMI, race/ethnicity, infertility diagnosis, and EMT at trigger, the estradiol cohort had a significantly increased odds of miscarriage versus the entire reference cohort (2.46, 95 % confidence interval [1.18, 5.14], p = 0.02). Thus, although estradiol supplementation had a statistically significant increase in EMT compared to IUI cycles with thin pre-ovulatory EMT (<7 mm), this change did not translate into improved IUI outcomes such as increased rates of clinical pregnancy and live birth or decreased rate of miscarriage. Our study suggests that supplemental estradiol does not appear to improve IUI outcomes.

Comparison of Letrozole and Clomiphene Citrate in Pregnancy Outcomes in Patients with Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis

Clomiphene citrate (CC) and letrozole are the predominant medical interventions for the management of infertility in patients with polycystic ovary syndrome (PCOS). To comprehensively summarize the evidence, a systematic review and meta-analysis of randomized clinical trials (RCTs) was carried out to assess the effect of letrozole and CC on pregnancy outcomes in PCOS patients. We searched PubMed/MEDLINE, Scopus, and Cochrane Central Register of Controlled Trials from inception to January 2023. We included RCTs conducted on PCOS women comparing letrozole to CC and assessing endometrial thickness, the number and size of follicles, and ovulation and pregnancy rates. The endpoints were summarized as risk ratio (RR) or standardized mean difference (SMD) with 95% confidence interval (CI) using the random-effects model. Heterogeneity was examined using the I2 statistic. Fifty trials met our inclusion criteria. The mean endometrial thickness was significantly higher in the letrozole group compared to CC group (SMD: 0.89; 95% CI: 0.49, 1.28; I2=97.72%); however, the number of follicles was higher in the CC group (SMD: -0.56; 95% CI: -0.96, -0.17; I2=96.34%). Furthermore, letrozole intake induced higher ovulation rate (RR: 1.20; 95% CI: 1.13, 1.26; I2=54.49%) and pregnancy rate (RR: 1.44; 95% CI: 1.28, 1.62; I2=65.58%) compared to CC. Compared to CC, letrozole has a positive effect on endometrial thickness, monofollicular development, and ovulation and pregnancy rates suggesting that letrozole may be a strong alternative to CC as a first-line medical intervention for chronic anovulation in PCOS women. Larger studies are warranted to further clarify these findings.

Polycystic ovary syndrome and thyroid disorder: a comprehensive narrative review of the literature

Background

Published data on the relationship between polycystic ovary syndrome (PCOS) and thyroid dysfunction are sparse and confusing.

Objective

To comprehensively review data available in the literature regarding the relationship between PCOS and the thyroid function, and its abnormalities.

Methods

Nine main areas of interest were identified and analyzed according to the available evidence: 1) Evaluation of thyroid function for PCOS diagnosis; 2) Epidemiology data on thyroid function/disorders in patients with PCOS, and vice versa; 3) Experimental data supporting the relationship between thyroid function/disorders and PCOS; 4) Effects of thyroid function/disorders on PCOS features, and vice versa; 5) Effect of thyroid alterations on the cardiometabolic risk in women with PCOS; 6) Effect of thyroid abnormalities on reproductive outcomes in women with PCOS; 7) Relationship between thyroid function/abnormalities in patients with PCOS who are undergoing fertility treatment; 8) Effect of treatments for thyroid diseases on PCOS; and 9) Effect of treatments for PCOS on thyroid function. An extensive literature search for specific keywords was performed for articles published from 1970 to March 2023 using PubMed and Web of Science. Data were reported in a narrative fashion.

Results

PCOS is a diagnosis of exclusion for which diagnosis is possible only after excluding disorders that mimic the PCOS phenotype, including thyroid dysfunctions. However, the tests and the cutoff values used for this are not specified. Many experimental and clinical data suggest a relationship between perturbations of the thyroid function and PCOS. Direct and unequivocal evidence on the effects of thyroid function/disorders on PCOS features are lacking. High thyroid-stimulating hormone levels and subclinical hypothyroidism may be associated with significant worsening of several intermediate endpoints of cardiometabolic risk in women with PCOS. Thyroid abnormalities may worsen reproductive outcomes, especially in patients undergoing fertility treatment. To date, there are no data demonstrating the efficacy of thyroid medications on fertility and cardiometabolic risk in women with PCOS. Lifestyle modification changes, metformin, and vitamin D seem to improve thyroid function in the general population.

Conclusion

PCOS and thyroid disorders are closely related, and their coexistence may identify patients with a higher reproductive and metabolic risk. Regular screening for thyroid function and thyroid-specific autoantibodies in women with PCOS, particularly before and during pregnancy, is highly recommended.

How to Choose the Optimal Starting Dose of Clomiphene Citrate (50 or 100 mg per Day) for a First Cycle of Ovulation Induction in Anovulatory PCOS Women?

RESEARCH QUESTION

Clomiphene citrate (CC) is one of the first-line treatments for ovulation induction in women with anovulatory polycystic ovary syndrome (PCOS). However, nearly 1 out of 2 women is resistant to 50 mg/day of CC. The objective of this study is to investigate the clinical, biological, and/or ultrasound factors that may predict the resistance to 50 mg/day of CC in the first cycle of treatment in women with anovulatory PCOS. This would make it possible to identify PCOS patients to whom the dose of 100 mg/day would be offered as of the first cycle.

DESIGN

A retrospective and monocentric study was conducted on 283 women with anovulatory PCOS who required the use of ovulation induction with CC (903 cycles).

RESULTS

During the first cycle of treatment, 104 patients (36.8%) were resistant to 50 mg/day of CC. Univariate regression analysis showed that patients who resisted 50 mg/day of CC had significantly higher BMI, waist circumference, serum levels of AMH, total testosterone, Δ4-androstenedione, 17-OHP, and insulin (p < 0.05), compared to patients ovulating with this dose. Serum levels of SHBG were significantly lower in patients resistant to 50 mg/day (p < 0.05). After multivariate analysis, only AMH and SHBG remained statistically significant (p = 0.01 and p = 0.001, respectively). However, areas under the ROC curves were weak (0.59 and 0.68, respectively).

CONCLUSION

AMH and SHBG are the only two parameters significantly associated with the risk of resistance to 50 mg/day of CC. However, no satisfactory thresholds have been established to predict resistance to 50 mg CC.

Factors associated with spontaneous miscarriage risk in IUI treatment: A retrospectively cohort of 31,933 cycles

To determine the factors associated with intrauterine insemination (IUI) miscarriages and reduce the IUI miscarriage rate, a retrospective study was performed by reviewing 31,933 IUI cycles from 2006 to 2018. The overall there were 14.50% clinical pregnancies, and 16.74% miscarriages. Logistic regression revealed the following three predictive variables: females aged ≥ 35 years (odds ratio [OR] = 2.131; p < 0.001), spontaneous miscarriage history (OR = 1.513; p = 0.005), and ovarian stimulation schemes such as clomiphene citrate (CC) (OR = 1.459; p = 0.003). The natural cycle led to a lower miscarriage rate for patients without spontaneous miscarriage history both for those over 35 years old (OR = 0.402; p = 0.034) and for those under 35 years old (OR = 0.806; p = 0.017). Gonadotropin (Gn) showed the lowest miscarriage rate for patients without abortion history, though no significant differences were found. Patients under 35 with a history of miscarriage were protected from miscarriage by using CC and Gn together (OR = 0.516; p = 0.032). No significant differences were found between various ovarian protocols when patients with abortion history were aged ≥ 35 years (p = 0.606). CC + Gn showed the lowest miscarriage rate. In conclusion, the natural cycle could be suggested for infertility couples to minimize abortion risk. When ovarian induction is required, CC + Gn had the lowest miscarriage rate for women with a history of spontaneous miscarriage while Gn is more successful for individuals without such a history.

Recent clomiphene citrate exposure does not impact subsequent clinical outcomes in single euploid frozen embryo transfer cycles

STUDY QUESTION

Do infertile couples who recently utilized clomiphene citrate (CC) for ovulation induction or ovarian stimulation (<90 days previously) followed by a single euploid embryo transfer (SEET) have lower implantation potential compared with patients who were not exposed to CC within 90 days before embryo transfer (ET)?

SUMMARY ANSWER

There does not appear to be an association between recent CC exposure and lower implantation potential in patients who undergo a frozen embryo transfer (FET) of euploid embryos.

WHAT IS KNOWN ALREADY

Clomiphene has been found to be associated with lower pregnancy rates when compared against other ovarian stimulation medications. The majority of published research about the effects of CC on implantation potential suggest an anti-estrogenic effect on the endometrium. Quality evidence and information about utilization of CC and its effect on implantation potential after euploid ETs is lacking in the literature.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study with propensity score matching was carried out. We included all patients that underwent an autologous SEET from September 2016 to September 2022 at a single academic-private ART center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study group included patients that had utilized CC during either ovulation induction cycles and/or controlled ovarian stimulation at least 90 days before FET. A propensity score-matched control group of patients that were unexposed to CC within 90 days prior to SEET was used for comparisons. The primary outcome was positive pregnancy test (defined as a positive serum β-hCG measured 9 days after ET), with other outcomes including clinical pregnancy, ongoing pregnancy, biochemical pregnancy loss, and clinical pregnancy loss rates per SEET. Multivariate regression analyses fitted with generalized estimating equations were utilized to analyze if there was an association between CC utilization and IVF outcomes. Furthermore, the study evaluated the cumulative effect of CC and endometrial receptivity in vivo and subsequent IVF outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 593 patients with utilization of CC in <90 days before ET were compared with 1779 matched controls. Positive pregnancy test rates were comparable among the control group and the CC exposed groups, respectively (74.3% versus 75.7%, P = 0.79), as were clinical pregnancy (64.0% versus 65.0%, P = 0.60), ongoing pregnancy (51.8% versus 53.2%, P = 0.74), biochemical pregnancy loss (15.7% versus 14.03%, P = 0.45), and clinical pregnancy loss rates were also comparable among cohorts (17.1% versus 18.1%, P = 0.71). No association was found between utilization of clomiphene and lower implantation rates (adjusted odds ratio 0.95, 95% CI 0.76-1.18). Also, no differences were observed in sub-analyses based on multiple CC utilization periods. Finally, no association was found between the number of consecutive cumulative clomiphene cycles and sub-optimal IVF outcomes.

LIMITATIONS, REASONS FOR CAUTION

The study has inherent bias that originated from its retrospective design. Serum levels of CC were not measured and sample size for the sub-analyses was small.

WIDER IMPLICATIONS OF THE FINDINGS

There does not appear to be an association between recent CC exposure and lower implantation potential in patients who undergo a FET of euploid embryos. This finding remains consistent, even in patients who undergo multiple, consecutive clomiphene cycles prior to ET. There were no long-term effects of CC on endometrial development and clinical characteristics examined in this study. Patients that utilized CC medication prior to a SEET cycle for either ovarian stimulation or ovulation induction, can be assured that there is no evidence of a residual effect of recent CC administration that could jeopardize their pregnancy probability.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was received for the realization of this study. A.C. is advisor and/or board member of Sema4 (stakeholder in data) and Progyny. The other authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Low-dose clomiphene citrate does not reduce implantation and live birth rates in otherwise unstimulated modified natural cycle IVF-retrospective cohort study

RESEARCH QUESTION

Does antioestrogen effect of clomiphene citrate (CC) on the endometrium reduce implantation and thereby decrease pregnancy and live birth rate per transferred embryo?

METHODS

In this cohort, unstimulated IVF cycles modified with clomiphene citrate (CC-NC-IVF) and unstimulated, natural IVF cycles (NC-IVF) conducted between 2011 and 2016 were included. CC was applied in a dosage of 25mcg per day, starting on cycle day 7 until ovulation trigger day. Primary outcomes were clinical pregnancy rate, defined as amniotic sac visible in ultrasound, and live birth rate per transferred embryo. Miscarriage rate calculated as amniotic sac not ending in a live birth was secondary outcome. A modified mixed-effect Poisson regression model was applied, and adjustments were made for female age, parity, type and cause of infertility. Additionally, stratification by parity and age was performed.

RESULTS

Four hundred and ninety-nine couples underwent a total of 1042 IVF cycles, 453 being NC-IVF and 589 being CC-NC-IVF cycles. Baseline characteristics of both groups did not differ. Addition of CC did neither decrease clinical pregnancy rate (aRR 0.86; 95% CI 0.67-1.12) nor live birth rate per transferred embryo (aRR 0.84; 95% CI 0.62-1.13) in comparison with NC-IVF. Miscarriage rate did not differ between CC-NC-IVF and NC-IVF (aRR 0.95; 95% CI 0.57-1.57).

CONCLUSION

Low-dose CC does not reduce pregnancy or live birth rate per transferred embryo. It can be used in infertility treatment without negatively affecting the endometrium and implantation.

Letrozole Compared With Clomiphene Citrate for Polycystic Ovarian Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the effect of letrozole and clomiphene citrate in women with infertility and polycystic ovarian syndrome (PCOS).

METHODS OF STUDY SELECTION

MEDLINE through PubMed, Web of Science, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched for relevant studies from inception to February 1, 2022. Two reviewers retrieved, filtered, and extracted data independently using the bibliographic software EndNote X9 and Excel workbook. We included randomized controlled trials (RCTs) reporting ovulation induction outcomes in women with infertility and PCOS treated with either letrozole or clomiphene citrate followed by timed intercourse or intrauterine insemination. The data were merged into a mean difference or risk ratio (RR) with 95% CI, depending on variable types.

TABULATION, INTEGRATION, AND RESULTS

Data collection and organization were conducted in accordance with the 2020 PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) statement. Twenty-nine RCTs were eligible, which included 3,952 women and 7,633 ovulation induction cycles. We acquired evidence from 22 RCTs for the ovulation rate, 28 RCTs for the clinical pregnancy rate, and eight RCTs for live-birth rate. Pooled analysis indicated that letrozole treatment prevailed against clomiphene citrate in ovulation rate (RR 1.14, 95% CI 1.06-1.21, P <.001), clinical pregnancy rate (RR 1.48, 95% CI 1.34-1.63, P <.001), and live-birth rate (RR 1.49, 95% CI 1.27-1.74, P <.001).

CONCLUSIONS

Letrozole was associated with improved ovulation, pregnancy, and live-birth rates compared with clomiphene citrate. We recommend letrozole over clomiphene citrate as an ovulation induction drug in women with infertility and PCOS, although the quality of the evidence is mixed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42022308777.

Association between endometrial thickness before ovulation, live birth, and placenta previa rates in clomiphene citrate-treated cycles

BACKGROUND

Although a recent study reported that the pregnancy outcomes in the first trimester were more correlated with endometrial thickness on the day of the trigger than with endometrial thickness on the day of single fresh-cleaved embryo transfer, it remains unclear whether endometrial thickness on the day of the trigger can predict live birth rate after a single fresh-cleaved embryo transfer.

OBJECTIVE

This study aimed to examine whether endometrial thickness on the trigger day is associated with live birth rates and whether modifying the single fresh-cleaved embryo transfer criteria to reflect endometrial thickness on the trigger day improved the live birth rate and reduced maternal complications in a clomiphene citrate-based minimal stimulation cycle.

STUDY DESIGN

This was a retrospective study of the outcomes of 4440 treatment cycles of women who underwent single fresh-cleaved embryo transfer on day 2 of the retrieval cycle. From November 2018 to October 2019, single fresh-cleaved embryo transfer was performed when endometrial thickness on the day of single fresh-cleaved embryo transfer was ≥8 mm (criterion A). From November 2019 to August 2020, single fresh-cleaved embryo transfer was conducted when endometrial thickness on the day of the trigger was ≥7 mm (criterion B).

RESULTS

A multivariate logistic regression analysis revealed that increased endometrial thickness on the trigger day was significantly associated with an improvement in the live birth rate after single fresh-cleaved embryo transfer (adjusted odds ratio, 1.098; 95% confidence interval, 1.021-1.179). The live birth rate was significantly higher in the criterion B group than in the criterion A group (22.9% and 19.1%, respectively; P=.0281). Although endometrial thickness on the day of single fresh-cleaved embryo transfer was sufficient, the live birth rate tended to be lower when endometrial thickness on the trigger day was <7.0 mm than when endometrial thickness on the day of the trigger was ≥7.0 mm. The risk for placenta previa was reduced in the criterion B group when compared with the criterion A group (4.3% and 0.6%, respectively; P=.0222).

CONCLUSION

This study demonstrated an association of decreased endometrial thickness on the trigger day with low birth rate and a high incidence of placenta previa. A modification of the criteria for a single fresh-cleaved embryo transfer based on endometrial thickness may improve pregnancy and maternal outcomes.

GRADE Use in Evidence Syntheses Published in High-Impact-Factor Gynecology and Obstetrics Journals: A Methodological Survey

Objective: To identify and describe the certainty of evidence of gynecology and obstetrics systematic reviews (SRs) using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Method: Database searches of SRs using GRADE, published between 1 January 2016 to 31 December 2020, in the 10 "gynecology and obstetrics" journals with the highest impact factor, according to the Journal Citation Report 2019. Selected studies included those SRs using the GRADE approach, used to determine the certainty of evidence. Results: Out of 952 SRs, ninety-six SRs of randomized control trials (RCTs) and/or nonrandomized studies (NRSs) used GRADE. Sixty-seven SRs (7.04%) rated the certainty of evidence for specific outcomes. In total, we identified 946 certainty of evidence outcome ratings (n = 614 RCT ratings), ranging from very-low (42.28%) to low (28.44%), moderate (17.65%), and high (11.63%). High and very low certainty of evidence ratings accounted for 2.16% and 71.60% in the SRs of NRSs, respectively, compared with 16.78% and 26.55% in the SRs of RCTs. In the SRs of RCTs and NRSs, certainty of evidence was mainly downgraded due to imprecision and bias risks. Conclusions: More attention needs to be paid to strengthening GRADE acceptance and building knowledge of GRADE methods in gynecology and obstetrics evidence synthesis.

Clinical pregnancy outcomes prediction in vitro fertilization women based on random forest prediction model: A nested case-control study

The present study aimed to analyze the risk factors influencing the in vitro fertilization embryo transfer (IVF-ET) pregnancy and to construct a prediction model for clinical pregnancy outcome in patients receiving IVF-ET based on the predictors. In this nested case-control study, the data of 369 women receiving IVF-ET were enrolled. Univariate and multivariate Logistic regression analyses were conducted to identify the potential predictors. Ten-fold cross validation method was used to validate the random forest model for predicting the clinical pregnancy. The receiver operating characteristic curve was drawn to evaluate the prediction ability of the model. The importance of variables was shown according to Mean Decrease Gini. The data delineated that age (odds ratio [OR]= 1.093, 95% confidence interval [CI]: 1.036-1.156, P = .0010), body mass index (BMI) (OR = 1.094, 95%CI: 1.021-1.176, P = .012), 3 cycles (OR = 0.144, 95%CI: 0.028-0.534, P = .008), hematocrit (HCT) (OR = 0.865, 95% CI: 0.791-0.943, P = .001), luteinizing hormone (LH) (OR = 0.678, 95%CI: 0.549-0.823, P < .001), progesterone (P) (OR = 2.126, 95%CI: 1.112-4.141, P = .024), endometrial thickness (OR = 0.132, 95%CI: 0.034-0.496, P = .003) and FSH (OR = 1.151, 95%CI: 1.043-1.275, P = .006) were predictors associated with the clinical pregnancy outcome of patients receiving IVF-ET. The results might provide a novel method to identify patients receiving IVF-ET with a high risk of poor pregnancy outcomes and provide interventions in those patients to prevent the occurrence of poor pregnancy outcomes.

Pregnancy outcomes after frozen-thawed embryo transfer using letrozole ovulation induction, natural, or programmed cycles

OBJECTIVE

To evaluate and compare pregnancy outcomes between letrozole ovulation induction, natural, and programmed frozen-thawed embryo transfer (FET) cycles in a population based in the United States.

DESIGN

Retrospective cohort study.

SETTING

Single university-affiliated infertility practice.

PATIENT(S)

A total of 3,148 FET cycles consisting of patients aged ≤45 years transferring blastocysts that were created from autologous oocytes between January 2015 and July 2021.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcome was the ongoing pregnancy rate (OPR) or live birth rate (LBR). The secondary outcomes included clinical pregnancy and clinical loss rates (CLRs).

RESULT(S)

The OPR/LBR was higher among letrozole FETs than among programmed FETs (adjusted risk ratio [aRR] 1.11, 95% confidence interval [CI] 1.02-1.21) but comparable to natural FETs (aRR 1.05, 95% CI 0.96-1.14). The OPR/LBR was comparable between natural and programmed FETs (aRR 1.06, 95% CI 0.99-1.13). The CLR was lower in the natural FET group than in the programmed FET group (aRR 0.62, 95% CI 0.46-0.84). There were no differences in CLRs between letrozole and programmed FETs and between letrozole and natural FETs. Among ovulatory women, the OPR/LBR among letrozole FETs was higher than that among programmed FETs (aRR 1.16, 95% CI 1.05-1.28). The CLR among ovulatory women was significantly lower in both letrozole FETs (aRR 0.44, 95% CI 0.22-0.87) and natural FETs (aRR 0.59, 95% CI 0.43-0.80) than in programmed FETs. Among anovulatory women, the OPR/LBR in the letrozole FET group was similar to that in the programmed FET group (aRR 0.95, 95% CI 0.79-1.13).

CONCLUSION(S)

Letrozole and natural FET clinical outcomes were improved compared with programmed FET outcomes.

Ovulation induction techniques in women with polycystic ovary syndrome

Anovulation is very common and has several different clinical manifestations, including amenorrhea, oligomenorrhea and abnormal uterine bleeding. Various mechanisms can cause anovulation. The clinical consequences and commonest chronic anovulatory disorder, polycystic ovary syndrome (PCOS), has a prevalence that ranges between 6 to 10% of the global population. While multiple causes can eventually result in PCOS, various methods have been described in the literature for its management, often without ascertaining the underlying cause. Ovulation Induction (OI) is a group of techniques that is used in women with PCOS who are looking to conceive and are unbale to do so with natural means. This narrative review presents a summary of the current evidence and available techniques for OI in women with PCOS, highlighting their performance and applicability.

Frozen Blastocyst Embryo Transfer: Comparison of Protocols and Factors Influencing Outcome

Background: Various factors, including treatment protocols, can influence the outcomes of frozen embryo transfers (FETs). The study objectives were to compare different endometrial preparation protocols of FET cycles and to evaluate the factors, including the endometrial thickness (ET), that affect outcomes. Methods: This observational cohort study involved 5037 women undergoing FETs at eight tertiary clinics in the UK between January 2016 and March 2019. The endometrial preparation protocols used were natural cycle (NC-FETs), artificial hormone support cycle with oestradiol valerate but without pituitary downregulation (AC-FETs) and artificial hormone support cycle with agonist downregulation (ACDR-FETs). Results: The mean (±SD) ages across NC-FET, AC-FET and ACDR-FET groups were 36.5 (±4.2), 35.9 (±5.0) and 36.4(±4.9) years, respectively. LBRs were comparable (40.7%, 175/430; 36.8%, 986/2658; and 36.7%, 716/1949, respectively) across the three groups. Clinical pregnancy, implantation, multiple pregnancies, miscarriage and ectopic pregnancy rates were also similar. In the regression analysis of variables including age, duration of infertility, number of embryos transferred, protocol type and endometrial thickness, age was the only significant predictor of LBRs, although its predictive ability was poor (AUC: 0.55). With the overall LBR of the study population being 37.1%, the post-test probability of a live birth at an ET of <5 mm was 0%, and at 5–5.9, 6–6.9, 7–7.9 and 8–8.9 mm, the probabilities were 16.7%, 33.8%, 36.7% and 37.7%, respectively. The LBR remained above 35% up to the 14–14.9 mm range and then declined gradually to 23% for the 17–25 mm range. Conclusions: The FET outcomes were similar for the three protocols used for endometrial preparation. The protocol type and endometrial thickness were not predictive of FET outcomes; age was the only predictive variable, despite its low predictive ability.

Comparison of Tamoxifen and Clomiphene Citrate for Ovulation Induction in Women with Polycystic Ovarian Syndrome: A Prospective Study

Background:

The purpose of this study was to compare the efficacy of tamoxifen and clomiphene citrate in induction of ovulation in women with PCOS and anovulation.

Methods:

In this prospective cohort study, 104 women with PCOS and primary infertility were enrolled after fulfilling the inclusion and exclusion criteria. The patients were allocated in two groups; group A (n=54) received tamoxifen 40 mg once daily (Days 3–7) and group B (n=50) received clomiphene citrate 100 mg once daily (Days 3–7). Serial ultrasounds were done till the administration of human chorionic gonadotropin (hCG). The ovulation and pregnancy rates in both groups were compared. The number of dominant follicles, estradiol levels, and endometrial thickness were also studied. Comparison was done using chi-square and student’s t-test and a p-value of less than 0.05 was considered statistically significant.

Results:

The number of dominant follicles and serum estradiol levels were significantly higher in group B (p<0.05), whereas the endometrial thickness was significantly more in group A (p<0.05). The ovulation rates were similar in both groups (66.6% vs. 70%, p=0.715). Pregnancy rate per treatment cycle and per ovulatory cycle was marginally higher in group A (14.81% and 22.22%, respectively), as compared to group B (14% and 20%, respectively), but the difference was not statistically significant (p>0.05).

Conclusion:

Tamoxifen and clomiphene citrate are both equally effective in induction of ovulation and achieving a pregnancy in women with PCOS.

Estrogen Biosynthesis and Signal Transduction in Ovarian Disease

Estrogen mainly binds to estrogen receptors (ERs) to regulate menstrual cycles and reproduction. The expression of ERalpha (ERα), ERbeta (ERβ), and G-protein-coupled estrogen receptor (GPER) mRNA could be detected in ovary, suggesting that they play an important role in estrogen signal transduction in ovary. And many studies have revealed that abnormal expression of estrogen and its receptors is closely related to ovarian disease or malignant tumors. With the continuous development and research of animal models, tissue-specific roles of both ERα and ERβ have been demonstrated in animals, which enable people to have a deeper understanding of the potential role of ER in regulating female reproductive diseases. Nevertheless, our current understanding of ERs expression and function in ovarian disease is, however, incomplete. To elucidate the biological mechanism behind ERs in the ovary, this review will focus on the role of ERα and ERβ in polycystic ovary syndrome (PCOS), ovarian cancer and premature ovarian failure (POF) and discuss the major challenges of existing therapies to provide a reference for the treatment of estrogen target tissue ovarian diseases.

Application of ultrasound markers measured at different time points of COH cycle in the prediction of ovarian response for individualised ovulation induction

The purpose of this study was to evaluate the predictive value of ultrasound markers measured at different time points of the controlled ovarian hyperstimulation (COH) cycle on ovarian response and outcome indicators in the IVF-ET cycle. According to the oestrogen level and the number of retrieved oocytes, patients who planned for COH treatment were separated into low-response group, normal and high-response group. The ovarian stromal artery flow parameters on the day of pituitary down-regulation, day 1, day 7, day 10, and the day of hCG injection were collected prospectively. We also have collected the data of cumulus oophorus count on the day of hCG injection by transvaginal sonography. Compared with the low-response group, on the first day of the COH cycle PI, RI, and S/D were lower in the high-response group than they were in the low-response group (p < .05). PSV and EDV were significantly higher in the high-response group than they were in the low-response group (p < .01), and the PSV on the first day of the COH cycle have statistical significance in predicting the number of high-quality embryos. The number of cumulus oophorus on the day of hCG injection has statistical significance in predicting the number of oocytes retrieved and fertilised oocytes. We conclude that the ovarian stromal artery flow parameters on the first day of the COH cycle and cumulus oophorus count on hCG injection day can serve as efficient indicators for an early assessment of ovarian response and individualised ovulation induction.IMPACT STATEMENTWhat is already known on this subject? AMH, AFC, and the age of the patient are well-known effective parameters for the evaluation of ovarian response, but these are insufficient and full of individual differences. Some researchers have investigated the value of colour Doppler ultrasound and cumulus oophorus in assessing ovarian response, but no definitive conclusion has been reached.What do the results of this study add? The hemodynamic parameters of ovarian stromal artery on the first day of the COH cycle and the number of cumulus oophorus on the day of hCG injection detected by Transvaginal Colour Doppler Sonography (TV-CDS) could be used to predict the ovarian response.What are the implications of these findings for clinical practice and/or further research? Ovarian stromal artery flow parameters and cumulus oophorus detected by TV-CDS can potentially be offered as a complementary parameter for ovarian reserve.

The efficiency of low-dose letrozole plus clomiphene citrate for ovulation induction in intrauterine insemination cycles: A randomized clinical trial

OBJECTIVE

To investigate if combination therapy with clomiphene citrate (CC) plus letrozole (L) was associated with a higher efficacy than L and CC alone in patients undergoing ovarian induction plus intrauterine insemination.

METHODS

The present multicenter randomized controlled clinical trial was performed between 2018 and 2020. Participants were randomized into three groups: L (n = 167; 5 mg/day), CC (n = 167; 100 mg/day), and L + CC (n = 167) (2.5 mg/day + 50 mg/day) from day 3. Ovarian stimulation was continued with the appropriate dose of gonadotropins daily starting from day 8 and continued until follicular size was 20 mm or more followed by administration of human chorionic gonadotropin (10 000 IU). Semen samples were prepared by direct swim-up technique.

RESULTS

In the CC group, gonadotropin dose was significantly higher but endometrial thickness was significantly lower compared with other groups. Number of follicles of 18 mm or more was significantly lower in the L group compared with the other two groups. Number of follicles less than 15 mm was meaningfully higher in the CC group compared with the other groups. In the L + CC group, total and largest follicular size, and the rates of chemical, clinical, and ongoing pregnancy, and live birth were significantly higher compared with other groups.

CONCLUSION

Combination therapy with L + CC was superior to either L or CC for achieving pregnancy in women undergoing ovarian induction plus intrauterine insemination.

Nomogram to predict an endometrial thickness above 7.5 mm in the frozen embryo transfer cycle of women with a thin endometrium

RESEARCH QUESTION

Which characteristics of patients with a thin endometrium (endometrial thickness [EMT] ≤7.5 mm on human chorionic gonadotrophin [HCG] trigger day) suggest the possibility of an EMT >7.5 mm in the subsequent frozen cycle?

DESIGN

Data were collected from the university-affiliated Centre for Reproductive Medicine between January 2013 and September 2019. Multivariable logistic regression was used to generate the final prediction model and construct the nomogram. Model performances were quantified by discrimination and calibration.

RESULTS

The predictive variables that entered the final model were: hysteroscopic adhesiolysis history, polycystic ovary syndrome status, application of clomiphene in the ovarian stimulation process, the ovarian stimulation protocol and the endometrial preparation protocol. The receiver operating characteristic (ROC) curve for the final model and validation cohort was 0.760 (95% confidence interval [CI] 0.722-0.797) and 0.713 (95% CI 0.664-0.759), respectively. Discrimination performed well in both the modelling and validation cohorts.

CONCLUSIONS

In women with a thin endometrium (EMT ≤7.5 mm on HCG trigger day), the absence of a hysteroscopic adhesiolysis history, the presence of polycystic ovary syndrome, the application of clomiphene in the ovarian stimulation process, the application of a gonadotrophin-releasing hormone agonist short protocol, mild stimulation protocol, natural cycle protocol, and natural cycle for endometrial preparation are prognostic for an increased possibility of an EMT >7.5 mm in the subsequent frozen cycle.

Higher ovulation rate with letrozole as compared with clomiphene citrate in infertile women with polycystic ovary syndrome: a systematic review and meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common cause of anovulatory infertility. According to the latest guidelines, letrozole should be considered as the first-line pharmacological treatment for women with WHO Group II anovulation or PCOS. However, the use of letrozole as an ovulation induction agent is not FDA or EMA approved, and its use is "off-label." The main concern with respect to letrozole regards its potential teratogenic effect on the fetus.

PURPOSE

To determine whether the probability of ovulation is higher with letrozole as compared to clomiphene citrate (CC) in anovulatory women with PCOS.

METHODS

Randomized controlled trials (RCTs) comparing letrozole versus CC used for ovulation induction in infertile women with PCOS followed by timed intercourse (TI) or intrauterine insemination (IUI) were included in this meta-analysis. Primary outcome was ovulation. Secondary outcomes were live birth, clinical pregnancy, miscarriage, multiple pregnancy, and congenital anomalies. Subgroup analysis included patients who received letrozole or CC as first-line treatment, and patients with PCOS diagnosed according to the Rotterdam criteria.

RESULTS

Twenty-six RCTs published between 2006 and 2019, involving 4168 patients who underwent 8310 cycles of ovulation induction, were included. The probability of ovulation was significantly higher in letrozole as compared to CC cycles (RR: 1.148, 95% CI: 1.077 to 1.223, 3017 women, 19 trials, I²: 47.7%, low-quality evidence).

CONCLUSION

A higher probability of ovulation is expected in infertile patients with PCOS treated with letrozole as compared to CC. The higher ovulation rate might have contributed to the higher clinical pregnancy and live birth rate. This finding is also true for patients who were administered letrozole as first-line treatment.

TRIAL REGISTRATION

CRD42019125166.

Poor Endometrial Proliferation After Clomiphene is Associated With Altered Estrogen Action

CONTEXT

Suboptimal endometrial thickening is associated with lower pregnancy rates and occurs in some infertile women treated with clomiphene.

OBJECTIVE

To examine cellular and molecular differences in the endometrium of women with suboptimal vs optimal endometrial thickening following clomiphene.

METHODS

Translational prospective cohort study from 2018 to 2020 at a university-affiliated clinic. Reproductive age women with unexplained infertility treated with 100 mg of clomiphene on cycle days 3 to 7 who developed optimal (≥8mm; n = 6, controls) or suboptimal (<6mm; n = 7, subjects) endometrial thickness underwent preovulatory blood and endometrial sampling. The main outcome measures were endometrial tissue architecture, abundance and location of specific proteins, RNA expression, and estrogen receptor (ER) α binding.

RESULTS

The endometrium of suboptimal subjects compared with optimal controls was characterized by a reduced volume of glandular epithelium (16% vs 24%, P = .01), decreased immunostaining of markers of proliferation (PCNA, ki67) and angiogenesis (PECAM-1), increased immunostaining of pan-leukocyte marker CD45 and ERβ, but decreased ERα immunostaining (all P < .05). RNA-seq identified 398 differentially expressed genes between groups. Pathway analysis of differentially expressed genes indicated reduced proliferation (Z-score = -2.2, P < .01), decreased angiogenesis (Z-score = -2.87, P < .001), increased inflammation (Z-score = +2.2, P < .01), and ERβ activation (Z-score = +1.6, P < .001) in suboptimal subjects. ChIP-seq identified 6 genes bound by ERα that were differentially expressed between groups (P < .01), some of which may play a role in implantation.

CONCLUSION

Women with suboptimal endometrial thickness after clomiphene exhibit aberrant ER expression patterns, architectural changes, and altered gene and protein expression suggesting reduced proliferation and angiogenesis in the setting of increased inflammation.

Randomised controlled trial on the effect of clomiphene citrate and gonadotropin dose on ovarian response markers and IVF outcomes in poor responders

STUDY QUESTION

Does the gonadotropin (GN) starting dose and the addition of clomiphene citrate (CC) during the early follicular phase influence oocyte yield in poor responders undergoing ovarian stimulation for IVF treatment?

SUMMARY ANSWER

The number of retrieved oocytes was similar regardless of the starting dose of GN (150 versus 450 IU) with or without the addition of CC (100 mg from Day 3 to 7 versus placebo).

WHAT IS KNOWN ALREADY

ART in poor responders is a challenge for patients and clinicians. So far, randomised controlled studies addressing interventions have shown that neither the GN dose nor the addition of oral medication has any significant effect on the clinical outcome of ART in poor responders. There is limited knowledge about the effect of GN starting dose in combination with CC during the early follicular phase of ovarian stimulation on ovarian response markers and ART outcome.

STUDY DESIGN, SIZE, DURATION

This single-centre randomised double-blinded clinical trial was conducted from August 2013 until November 2017. Using the Bologna criteria, 220 of 2288 patients (9.6%) were identified as poor responders and 114 eligible participants underwent ovarian stimulation in a GnRH-antagonist protocol for ART.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The participants were equally randomised to one of four treatment arms: Group A (n = 28) received 100 mg CC (Day 3-7) and a starting dose of 450 IU HMG, Group B (n = 29) received 100 mg CC and a starting dose of 150 IU HMG, Group C (n = 30) received placebo and a starting dose of 450 IU HMG and Group D (n = 27) received placebo and a starting dose of 150 IU HMG. Serum levels of FSH, LH, estradiol and progesterone were measured on Day 1 and 5 and on the day of ovulation induction. Available embryos were cultured up to the blastocyst stage and were always transferred in the same cycle. The primary outcome was the number of oocytes collected after ovarian stimulation. Other outcome measures were response to ovarian stimulation, embryo development and obstetrical outcome.

MAIN RESULTS AND THE ROLE OF CHANCE

All study participants (n = 114) fulfilled at least two of the Bologna criteria for poor responders. Median age of the study population was 38.5 years. There were 109 patients who underwent oocyte retrieval. The number of oocytes retrieved was similar among the groups (±SD; 95% confidence intervals); A: 2.85 (±0.48; 2.04-3.98), B: 4.32 (±0.59; 3.31-5.64); C: 3.33 (±0.52; 2.45-4.54); D: 3.22 (±0.51; 2.36-4.41); P overall = 0.246. However, ovarian stimulation with 150 IU plus CC resulted in a higher number of blastocysts compared to ovarian stimulation with 450 IU plus CC (±SD; 95% confidence intervals); A: 0.83 (±0.15; 0.58-1.2), B: 1.77 (±0.21; 1.42-2.22); P overall = 0.006. Mean FSH serum levels were lower in the groups with a starting dose of 150 IU. Adding CC did not affect mean serum FSH levels. There were no differences in estradiol concentrations among the groups. Endometrial thickness was lower in the groups receiving CC. The overall live birth rate (LBR) was 12.3%, and the cumulative LBR was 14.7%.

LIMITATIONS, REASONS FOR CAUTION

The trial was powered to detect differences in neither the number of blastocysts nor the LBR, which would be the preferable primary outcome of interventional trials in ART.

WIDER IMPLICATIONS OF THE FINDINGS

We found that ovarian stimulation with 150 IU gonadotrophin in combination with 100 mg CC produced more blastocysts. The effect of adding CC to GN on LBR in poor responders remains to be proven in randomised trials. High GN doses (450 IU) resulted in high FSH serum levels but increased neither the estradiol levels nor the number of retrieved oocytes, implying that granulosa cell function is not improved by high FSH serum levels. Lower starting doses of GN lead to a reduction of costs of medication. The small but significant difference in blastocyst formation and the lower FSH levels in the treatment groups receiving less GN may be an indication of better oocyte quality with higher developmental competence.

STUDY FUNDING/COMPETING INTEREST(S)

The costs for the HMG used for ovarian stimulation were provided by IBSA Switzerland. The study was also supported by the Repronatal Foundation, Basel, Switzerland. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

NCT01577472.

TRIAL REGISTRATION DATE

13 April 2012.

DATE OF FIRST PATIENT’S ENROLMENT

August 2013.

Effect of gonadotropins and endometrial thickness on pregnancy outcome in patients with unexplained infertility or polycystic ovarian syndrome undergoing intrauterine insemination

Objective

The purpose of this study was to investigate the effect of gonadotropin dose and endometrial thickness (EMT) on pregnancy outcome in patients undergoing intrauterine insemination (IUI).

Methods

We retrospectively analyzed data from 361 patients with unexplained infertility or polycystic ovarian syndrome (PCOS) who underwent 930 IUI cycles treated with gonadotropins. Then, we measured the effects of gonadotropins and EMT on the clinical pregnancy rate. Finally, we assessed the association of various doses of gonadotropins on EMT.

Results

The dose of gonadotropins given and thickness of the endometrium were higher in the pregnancy group than in the nonpregnancy group (636.0 vs. 600.0 IU for gonadotropin dose; 9.15 vs. 8.70 mm for EMT). Clinical pregnancy rates were significantly improved by increasing the dose of gonadotropins (9.1%, <450 IU; 16.2%, 450–599 IU; 18.6%, 600–749 IU, and 17.3%, ≥750 IU), or by increased EMT (0%, <5.0 mm; 12.2%, 5.0–6.9 mm; 15.5%, 7.0–14.0 mm; and 33.3%, >14.0 mm).

Conclusion

Increasing the dose of gonadotropins to stimulate one follicle to develop may benefit endometrial proliferation and improve IUI outcomes.

Gonadotrophins or clomiphene citrate in women with normogonadotropic anovulation and CC failure: does the endometrium matter?

STUDY QUESTION

Is endometrial thickness (EMT) a biomarker to select between women who should switch to gonadotropins and those who could continue clomiphene citrate (CC) after six failed ovulatory cycles?

SUMMARY ANSWER

Using a cut-off of 7 mm for EMT, we can distinguish between women who are better off switching to gonadotropins and those who could continue CC after six earlier failed ovulatory CC cycles.

WHAT IS ALREADY KNOWN

For women with normogonadotropic anovulation, CC has been a long-standing first-line treatment in conjunction with intercourse or intrauterine insemination (IUI). We recently showed that a switch to gonadotropins increases the chance of live birth by 11% in these women over continued treatment with CC after six failed ovulatory cycles, at a cost of €15 258 per additional live birth. It is unclear whether EMT can be used to identify women who can continue on CC with similar live birth rates without the extra costs of gonadotropins.

STUDY DESIGN, SIZE, DURATION

Between 8 December 2008 and 16 December 2015, 666 women with CC failure were randomly assigned to receive an additional six cycles with a change to gonadotropins (n = 331) or an additional six cycles continuing with CC (n = 335), both in conjunction with intercourse or IUI. The primary outcome was conception leading to live birth within 8 months after randomisation. EMT was measured mid-cycle before randomisation during their sixth ovulatory CC cycle. The EMT was available in 380 women, of whom 190 were allocated to gonadotropins and 190 were allocated to CC.

PARTICIPANTS/MATERIALS, SETTING, METHODS

EMT was determined in the sixth CC cycle prior to randomisation. We tested for interaction of EMT with the treatment effect using logistic regression. We performed a spline analysis to evaluate the association of EMT with chance to pregnancy leading to a live birth in the next cycles and to determine the best cut-off point. On the basis of the resulting cut-off point, we calculated the relative risk and 95% CI of live birth for gonadotropins versus CC at EMT values below and above this cut-off point. Finally, we calculated incremental cost-effectiveness ratios (ICER).

MAIN RESULTS AND THE ROLE OF CHANCE

Mid-cycle EMT in the sixth cycle interacted with treatment effect (P < 0.01). Spline analyses showed a cut-off point of 7 mm. There were 162 women (45%) who had an EMT ≤ 7 mm in the sixth ovulatory cycle and 218 women (55%) who had an EMT > 7 mm. Among the women with EMT ≤ 7 mm, gonadotropins resulted in a live birth in 44 of 79 women (56%), while CC resulted in a live birth in 28 of 83 women (34%) (RR 1.57, 95% CI 1.13–2.19). Per additional live birth with gonadotropins, the ICER was €9709 (95% CI: €5117 to €25 302). Among the women with EMT > 7 mm, gonadotropins resulted in a live birth in 53 of 111 women (48%) while CC resulted in a live birth in 52 of 107 women (49%) (RR 0.98, 95% CI 0.75–1.29).

LIMITATIONS, REASONS FOR CAUTION

This was a post hoc analysis of a randomised controlled trial (RCT) and therefore mid-cycle EMT measurements before randomisation during their sixth ovulatory CC cycle were not available for all included women.

WIDER IMPLICATIONS OF THE FINDINGS

In women with six failed ovulatory cycles on CC and an EMT ≤ 7 mm in the sixth cycle, we advise switching to gonadotropins, since it improves live birth rate over continuing treatment with CC at an extra cost of €9709 to achieve one additional live birth. If the EMT > 7 mm, we advise to continue treatment with CC, since live birth rates are similar to those with gonadotropins, without the extra costs.

STUDY FUNDING/COMPETING INTEREST(S)

The original MOVIN trial received funding from the Dutch Organization for Health Research and Development (ZonMw number: 80-82310-97-12067). C.B.L.A. reports unrestricted grant support from Merck and Ferring. B.W.M. is supported by a NHMRC Practitioner Fellowship (GNT1082548) and reports consultancy for Merck, ObsEva, IGENOMIX and Guerbet. All other authors have nothing to declare.

TRIAL REGISTRATION NUMBER

Netherlands Trial Register, number NTR1449

Use of clomiphene citrate protocol for controlled ovarian stimulation impairs endometrial maturity

INTRODUCTION

Despite recent advances in assisted reproduction techniques and recent knowledge regarding embryo and endometrium quality, implantation and birth rates remain low. The objective of this study was to investigate whether clomiphene citrate alters endometrial maturation in infertile patients.

METHODS

In a prospective self-matched cohort study, we assessed the ovulation of women in spontaneous and stimulated cycles (with clomiphene citrate). We determined the ovulation day by ultrasound scanning. In both cycles, we took four blood samples (BS1 - at early proliferative phase, BS2 - at mid proliferative phase, BS3 - after ovulation and BS4 - at mid luteal phase) to determine the serum concentrations of FSH, LH, estradiol and progesterone. We retrieved an endometrial biopsy five days after ovulation, followed by blinded analysis and classification according to Noyes criteria, in both cycles.

RESULTS

Twenty-two participants completed the study. There were significant differences in FSH BS3 (p=0.001), in LH BS3 and BS4 (p<0.001 and p=0.049, respectively), in estradiol BS2, BS3 and BS4 (p<0.001, p=0.024 and p<0.001, respectively) and in progesterone BS3 and BS4 (p=0.028 and p<0.001, respectively). Considering Noyes criteria, there was a one-day delay when comparing the stimulated cycle with the spontaneous cycle (p=0.004), and a two-day delay when comparing the stimulated cycle with the biopsy day.

CONCLUSION

This study indicates that ovarian stimulation with clomiphene citrate delays the endometrial maturity, and could possibly impair the implantation process due to asynchrony.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

Pregnancy Outcomes Following Letrozole Use in Frozen-thawed Embryo Transfer Cycles: A Systematic Review and Meta-analysis

While widely used for ovulation induction in assisted reproductive technology, the clinical efficacy of letrozole for endometrial preparation prior to frozen-thawed embryo transfer (FET) cycles remains yet to be elucidated. We performed a meta-analysis to compare pregnancy outcomes after letrozole use with those of other endometrial preparation protocols in patients undergoing FET. PubMed, Scopus, Embase and the Cochrane Library were searched for eligible studies. Clinical pregnancy rate (CPR), live birth rate (LBR) and birth defect rate (BDR) were analysed using odds ratio (OR) and 95% confidence interval (CI). A total of 10 studies representing 75 968 FET cycles were included. Comparable CPR and LBR were observed when comparing letrozole administration with natural cycle (OR 1.24, 95% CI: 0.69 – 2.24; OR 1.18, 95% CI: 0.60 – 2.32), artificial cycle (OR 1.46, 95% CI: 0.87 – 2.44; OR 1.39, 95% CI: 0.77 – 2.52), and artificial cycle with gonadotropin-releasing hormone agonist suppression (OR 1.11, 95% CI: 0.78 – 1.59; OR 1.18, 95% CI: 0.82 – 1.68). Pooled results of the limited studies comparing letrozole with human menopausal gonadotropin demonstrated a similar CPR between groups (OR 1.46, 95% CI: 0.29 – 7.21, two studies), but the letrozole group had a statistically lower LBR (OR 0.67, 95% CI: 0.52 – 0.86, one study). No increased BDR was observed in the letrozole group compared to natural cycles or artificial cycles (OR 0.98, 95% CI: 0.60 – 1.61; OR 1.39, 95% CI; 0.84 – 2.28). This pooled analysis supports the use of letrozole as an efficacious and safe alternative to mainstream regimens for endometrial preparation in FET cycles.

Serendipity in the search for "morning-after pills" led to clomiphene for the induction of ovulation

The approval of the oral contraceptive on June 23, 1960, by the United States Food and Drug Administration (FDA), changed society forever. For the first time, a pill designed and tested by men, supported by influential women, allowed women to control their fertility. For the first time, the FDA approved a medicine to be taken by humans without a disease. The chance discovery of a new group of medicines called nonsteroidal antiestrogens, created an opportunity for the pharmaceutical industry. These compounds were shown to be postcoital antifertility agents in rats and mice. In the 1960s, the development of a "morning-after pill" would have had an enormous market. Numerous companies focused discovery efforts to evaluate the development of their patented nonsteroidal antiestrogens: Merrell (clomiphene), Upjohn (U-11,100A), and ICI Pharmaceutical Division (ICI46,474). However, the antifertility effects of antiestrogens in rats and mice does not mean that the new medicine would be an antifertility agent in women. In this case, clomiphene did exactly the opposite of what it was predicted to prevent. Clomiphene became the first medicine to induce ovulation in subfertile women. This article describes the twists and turns of drug discovery and development over the past half century. The conclusion emphasizes the evolution of drug development over decades, based on fashions in medical research and discoveries in clinical pharmacology. As a result, new uses for old molecules, that started life as "nonsteroidal antiestrogens," have revolutionized women's health as members of the new group of medicines called selective estrogen receptor modulators.

Gonadal hormones and stroke risk: PCOS as a case study

It is well known that stroke incidence and outcome is sex-dependent and influenced by age and gonadal hormones. In post-menopausal and/or aged females, declining estrogen levels increases stroke risk. However, women who experience early menopause also have an increase in stroke risk. This suggests that, regardless of age, gonadal hormones regulate stroke risk and severity. This review discusses prolonged gonadal hormone dysfunction in a common female endocrine disorder known as polycystic ovarian syndrome, PCOS, and the associated increased risk of stroke due to resulting hyperandrogenism and metabolic comorbidities.

Design and evaluation of a novel nanodrug delivery system for reducing the side effects of clomiphene citrate on endometrium

BACKGROUND

Stimulation of ovulation with clomiphene citrate can cause side effects on endometrial receptivity. Formulation with nano-size may be an alternative therapy for women with ovulatory disorders. In this study, we investigated sustained-release clomiphene citrate by using Phosal-based formulation (PBF) and evaluate its decreased side effect on the endometrial receptivity.

METHODS

In the in-vitro study, CC loaded PBF was analyzed using Zetasizer, Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM). In the in-vivo study, 24 female mice were randomly divided into three groups: CC (5 mg/kg), CC/PBF (5 mg/kg) and SS (1 ml) daily administered and injected with 5 IU HCG and mated after two days. At day 4.5, pregnant mice were euthanized and endometrial tissue was extracted for quantitative polymerase chain reaction (Q-PCR) analysis.

RESULTS

The optimized PBF contained Phosal 50PG/glycerol in a 2:8 ratios (w/w) and the particle size of optimum formulation was 67 ± 0.30551 nm and the release of CC from CC-containing PBF was slightly faster in the first 24 h; wherein, 29% of CC was released, and 76% of CC was released up to 120 h. The mRNA levels of leukemia inhibitory factor (LIF), leukemia inhibitory factor receptor alpha (LIFR), HOXA10, Heparin-binding epidermal growth factor (HB-EGF), and epidermal growth factor (EGF) were significantly upregulated and MUC1 and PGR mRNA levels were significantly downregulated in the CC-containing PBF-treated animals compared with only CC group (P < 0.05).

CONCLUSION

Sustained release formulation of clomiphene citrate increased its targeting efficiency and improved the impact of the CC on implantation. Graphical abstract A new Phosal Based Formulation (PBF) was designed to decrease the side effects of Clomiphene citrate (CC) on endometrium. This drug formulation could react better during implantation by increasing the expression of genes involved in implantation. The in vivo study demonstrated that the CC-containing PBF in mice has a significantly higher endometrial receptivity, compared with the suspension.

Association between endometrial thickness and neonatal outcomes in intrauterine insemination cycles: a retrospective analysis of 1,016 live-born singletons

BACKGROUND

Decreased endometrial thickness (EMT) has been suggested to be associated with reduced birthweight of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) newborns. Considering the differences in ovarian stimulation degree and laboratory procedures between IVF/ICSI and IUI treatment, we aim to investigate whether EMT has any influence on IUI infant outcomes as well.

METHODS

This was a retrospective cohort study of 1016 patients who had singleton livebirths after IUI treatment cycles from January 2008 to December 2018 at a tertiary-care academic medical center in China. Patients were categorized into three groups by the 10th and 90th percentile of peak EMT: ≤7.6, 7.7-13.0 and ≥ 13.1 mm. The primary outcomes of the study were preterm birth (PTB), low birthweight (LBW) and small-for-gestational age (SGA). Multiple regression analyses were performed after controlling for a variety of potential confounders.

RESULTS

No significant differences were found among the three groups in gestational age, birthweight and birthweight Z-score. Compared with the EMT 7.7-13.0 mm group, the incidences of PTB, LBW and SGA were 5.5% (adjusted odds ratio [aOR] 0.81, 95% confidence interval [CI] 0.33-2.01), 6.4% (aOR 1.44, 95% CI 0.58-3.58) and 7.3% (aOR 1.21, 95% CI 0.53-2.76) in the EMT ≤7.6 mm group, respectively. Similarly, EMT ≥13.1 mm was not significantly associated with risks of PTB (aOR 0.63, 95% CI 0.24-1.65), LBW (aOR 0.57, 95% CI 0.17-1.95) and SGA (aOR 0.73, 95% CI 0.28-1.92). The odds of other adverse neonatal outcomes, including macrosomia, large-for-gestational age and major congenital malformations, did not show significant differences before and after adjustment in both EMT ≤7.6 and ≥ 13.1 mm groups.

CONCLUSIONS

EMT is not independently associated with adverse perinatal outcomes in IUI cycles. This novel finding would provide reassuring information for IUI patients with thin endometrial linings regarding their neonatal health. However, further prospective cohort studies with larger datasets are needed to confirm the conclusion.

Conventional and modern markers of endometrial receptivity: a systematic review and meta-analysis

BACKGROUND

Early reproductive failure is the most common complication of pregnancy with only 30% of conceptions reaching live birth. Establishing a successful pregnancy depends upon implantation, a complex process involving interactions between the endometrium and the blastocyst. It is estimated that embryos account for one-third of implantation failures, while suboptimal endometrial receptivity and altered embryo-endometrial dialogue are responsible for the remaining two-thirds. Endometrial receptivity has been the focus of extensive research for over 80 years, leading to an indepth understanding of the processes associated with embryo-endometrial cross-talk and implantation. However, little progress has been achieved to translate this understanding into clinically meaningful prognostic tests and treatments for suboptimal endometrial receptivity.

OBJECTIVE AND RATIONALE

The objective of this systematic review was to examine the evidence from observational studies supporting the use of endometrial receptivity markers as prognostic factors for pregnancy outcome in women wishing to conceive, in order to aid clinicians in choosing the most useful marker in clinical practice and for informing further research.

SEARCH METHODS

The review protocol was registered with PROSPERO (CRD42017077891). MEDLINE and Embase were searched for observational studies published from inception until 26 February 2018. We included studies that measured potential markers of endometrial receptivity prior to pregnancy attempts and reported the subsequent pregnancy outcomes. We performed association and accuracy analyses using clinical pregnancy as an outcome to reflect the presence of receptive endometrium. The Newcastle-Ottawa scale for observational studies was employed to assess the quality of the included studies.

OUTCOMES

We included 163 studies (88 834 women) of moderate overall quality in the narrative synthesis, out of which 96 were included in the meta-analyses. Studies reported on various endometrial receptivity markers evaluated by ultrasound, endometrial biopsy, endometrial fluid aspirate and hysteroscopy in the context of natural conception, IUI and IVF. Associations were identified between clinical pregnancy and various endometrial receptivity markers (endometrial thickness, endometrial pattern, Doppler indices, endometrial wave-like activity and various molecules); however, their poor ability to predict clinical pregnancy prevents them from being used in clinical practice. Results from several modern molecular tests are promising and further data are awaited.

WIDER IMPLICATIONS

The post-test probabilities from our analyses may be used in clinical practice to manage couples' expectations during fertility treatments (IUI and IVF). Conventionally, endometrial receptivity is seen as a dichotomous outcome (present or absent), but we propose that various levels of endometrial receptivity exist within the window of implantation. For instance, different transcriptomic signatures could represent varying levels of endometrial receptivity, which can be linked to different pregnancy outcomes. Many studies reported the means of a particular biomarker in those who achieved a pregnancy compared with those who did not. However, extreme values of a biomarker (as opposite to the means) may have significant prognostic and diagnostic implications that are not captured in the means. Therefore, we suggest reporting the outcomes by categories of biomarker levels rather than reporting means of biomarker levels within clinical outcome groups.

Effects of gonadotropin administration on clinical outcomes in clomiphene citrate-based minimal stimulation cycle IVF

PURPOSE

Exogenous gonadotropins (EGn) have been used occasionally in clomiphene citrate (CC)-based minimal stimulation cycles to compensate insufficient secretion of endogenous gonadotropin; however, the effectiveness of EGn supplementation remains unknown. In the present study, we assessed whether EGn improved pregnancy outcomes in CC-based minimal stimulation cycles.

METHODS

A total of 223 patients treated with CC and EGn (CC-EGn group) were matched one to one to patients treated with CC only (CC group) by propensity score matching. Embryonic and pregnancy outcomes were retrospectively compared between the groups.

RESULTS

The numbers of retrieved oocytes, fertilized oocytes, cleaved embryos, and cryopreserved blastocysts were increased in the CC-EGn group compared with the CC group. However, the cumulative live birthrate was comparable between the two groups. Although the increased number of retrieved oocytes was correlated significantly with improvement of the cumulative live birthrate in both groups, the correlation tended to be lower in the CC-EGn group than in the CC group (odds ratio, 1.193 vs 1.553).

CONCLUSIONS

In CC-based minimal stimulation cycles, the stimulation should be started with CC only, and EGn administration should be scheduled only if insufficient secretion of endogenous gonadotropin is observed in the late follicular phase.

Endometrial thickness as a biomarker for ongoing pregnancy in IUI for unexplained subfertility: a secondary analysis

STUDY QUESTION

What is, in couples with unexplained subfertility undergoing IUI, the impact of gonadotrophins compared to clomiphene citrate (CC) on endometrial thickness (EMT) in relation to ongoing pregnancy?

SUMMARY ANSWER

In women with unexplained subfertility undergoing IUI with ovarian stimulation, gonadotrophins lead to a thicker endometrium compared to CC, but this does not affect ongoing pregnancy rates.

WHAT IS KNOWN ALREADY

A systematic review and meta-analysis among couples with unexplained subfertility undergoing IUI with ovarian stimulation showed that women who conceived had, on average, a thicker endometrium than women who did not conceive, but this evidence is not robust due to a high level of heterogeneity. There was insufficient data to draw any conclusions on EMT and the effect on pregnancy outcomes.

STUDY DESIGN SIZE DURATION

We performed a secondary analysis of a multicentre randomized controlled superiority trial in couples with unexplained subfertility undergoing IUI with adherence to strict cancellation criteria. In total, 738 couples recruited between July 2013 and March 2016 were allocated to ovarian stimulation with gonadotrophins (n = 369) or with CC (n = 369) for a maximum of four IUI cycles. According to local protocol, recombinant FSH, urinary FSH or hMG was used. Natural conceptions and cancelled cycles were removed from this secondary analysis, as they do not provide any information on pregnancy in relation to stimulation after IUI. Ongoing pregnancy was defined as a positive heartbeat at or beyond 12 weeks of gestation.

PARTICIPANTS/MATERIALS SETTING METHODS

We first determined the difference in EMT between women randomized to gonadotrophins (75 IU) and CC (100 mg) over all cycles using a linear mixed model. We then investigated the association between EMT and ongoing pregnancy after IUI using a logistic regression model, adjusted for the allocated drug, number of dominant follicles, female age, BMI, duration of subfertility, primary or secondary subfertility, referral status, smoking status, cycle number and total motile sperm count. To conclude, we investigated the association between EMT and ongoing pregnancy by logistic regression separately in women allocated to gonadotrophins and in women allocated to CC.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 666 couples underwent 1968 IUI cycles. Of these, 330 couples were allocated to gonadotrophins, of which 85 conceived leading to ongoing pregnancy (rate per cycle 8.9%) and 336 couples were allocated to CC, of which 71 conceived leading to ongoing pregnancy (rate per cycle 7.0%) (relative risk (RR) 1.22, 95% CI 0.92 to 1.61). The mean EMT was 8.9 mm (SD 2.1) in women treated with gonadotrophins and 7.5 mm (SD 2.1) in women treated with CC (adjusted mean difference 1.4 mm; 95% CI: 1.1-1.7). The overall mean EMT was 8.4 mm (SD 2.2) in women that conceived leading to ongoing pregnancy and 8.2 mm (SD 2.2) in women that did not conceive (adjusted odds ratio (OR): 1.03 per 1 mm increase, 95% CI 0.95-1.12). There was no association between EMT and ongoing pregnancy in women treated with gonadotrophins or CC (OR: 1.01 per 1 mm increase, 95% CI 0.90-1.13, and 1.10 per 1 mm increase, 95% CI 0.99-1.23, respectively).

LIMITATIONS REASON FOR CAUTION

Since this is a secondary analysis, the data should be interpreted prudently as secondary analyses are prone to false-positive findings or could be underpowered to show associations that the study is not primarily set up for.

WIDER IMPLICATIONS OF THE FINDINGS

In women with unexplained subfertility and treated with IUI, gonadotrophins lead to a significantly thicker endometrium compared to CC, but there was no evidence of a consistent association between EMT in women treated with gonadotrophins or CC and the ongoing pregnancy rate. A relatively thin endometrium after CC is therefore not a valid reason to prefer gonadotrophins as the stimulation agent in IUI for unexplained subfertility.

STUDY FUNDING/COMPETING INTERESTS

The initial trial was funded by the Netherlands Organization for Health Research and Development (ZonMw) (Health Care Efficiency Research; project number: 80-83600-98-10 192). The EudraCT number for this trial was 2013-001034-18. Prof. Dr B.W.J.M. is supported by a NHMRC Practitioner Fellowship (GNT1082548). B.W.M. reports consultancy for Merck, ObsEva and Guerbet. The other authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

NTR 4057.

Letrozole Versus Clomiphene Citrate and Natural Cycle: Endometrial Receptivity During Implantation Window in Women With Polycystic Ovary Syndrome

OBJECTIVE

Numerous studies have reported on ovulation and pregnancy rates in patients with polycystic ovary syndrome (PCOS). However, relevant data on endometrial receptivity are limited. This study was conducted to compare endometrial receptivity during implantation windows among letrozole (LE), clomiphene citrate (CC), and natural cycle, and to assess the predictive value for pregnancy of observed indicators.

METHODS

This randomized controlled trial study enrolled 270 patients with PCOS. Patients were given LE (n=90) at a dose of 2.5mg/day or CC (n=90) at a dose of 50 mg/day on cycle days 5-9 for ovulation induction. Patients in the natural cycle group (n=90) did not receive any drug for ovulation induction. Endometrial ultrasonic parameters, integrin αvβ3, and vascular endothelial growth factor (VEGF) concentrations in uterine secretion were detected during the implantation window. The endometrial receptivity, ovulation rate, pregnancy rates, and predictive value of observed indicators for pregnancy were analyzed.

RESULTS

The successful ovulation rate did not differ between the LE group and CC group (P>0.05). Endometrial ultrasonic parameters [endometrial thickness (ET), endometrial volume (EV), vascularization index (VI), flow index (FI), vascularization flow index (VFI)], integrin αvβ3, and VEGF concentrations in uterine fluid were significantly higher in the LE group compared with the CC group and natural cycle group (P<0.05). The clinical pregnancy and ongoing pregnancy rates of the LE group were significantly higher than in the CC group (P<0.05). Endometrial ultrasonic parameters (VI, FI, and VFI), integrin αvβ3, and VEGF concentrations in uterine fluid of all pregnancy groups were significantly higher compared with the no pregnancy group (P<0.05), and the above parameters in ongoing pregnancy were significantly higher than in biochemical pregnancy (P<0.05). The endometrial FI during the implantation window had the highest predictive value for pregnancy (AUC=0.889). The integrin αvβ3 in uterine fluid had better predictive value (AUC=0.876) than VEGF.

CONCLUSIONS

Endometrial receptivity during the implantation window of LE is superior to CC in PCOS women, which may be related to higher clinical pregnancy and ongoing pregnancy rates. Endometrial FI examined by 3-D power Doppler, and integrin αvβ3 in uterine secretion during the implantation window, could be preferable non-invasive predictor markers for pregnancy.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn, ChiCTR1900023423.

Medical and Surgical Treatment of Reproductive Outcomes in Polycystic Ovary Syndrome: An Overview of Systematic Reviews

Polycystic ovary syndrome (PCOS) is a common, complex condition that affects up to 18% of reproductive- aged women, causing reproductive, metabolic and psychological dysfunctions. We performed an overview and appraisal of methodological quality of systematic reviews that assessed medical and surgical treatments for reproductive outcomes in women with PCOS. Databases (MEDLINE, EMBASE, CINAHL PLUS and PROSPERO) were searched on the 15th of September 2017. We included any systematic review that assessed the effect of medical or surgical management of PCOS on reproductive, pregnancy and neonatal outcomes. Eligibility assessment, data extraction and quality assessment by the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) tool were performed in duplicate. We identified 53 reviews comprising 44 reviews included in this overview; the majority were moderate to high quality. In unselected women with PCOS, letrozole was associated with a higher live birth rate than clomiphene citrate (CC), while CC was better than metformin or placebo. In women with CC-resistant PCOS, gonadotrophins were associated with a higher live birth rate than CC plus metformin, which was better than laparoscopic ovarian drilling (LOD). LOD was associated with lower multiple pregnancy rates than other medical treatments. In women with PCOS undergo- ing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI), the addition of metformin to gonadotro- phins resulted in less ovarian hyperstimulation syndrome (OHSS), and higher pregnancy and live birth rates than gonadotrophins alone. Gonadotrophin releasing hormone (GnRH) antagonist was associated with less OHSS, gonadotrophin units and shorter stimulation length than GnRH agonist. Letrozole appears to be a good first line treatment and gonadotrophins, as a second line treatment, for anovulatory women with PCOS. LOD results in lower multiple pregnancy rates. However, due to the heterogeneous nature of the included popula- tions of women with PCOS, further larger scale trials are needed with more precise assessment of treatments according to heterogeneous variants of PCOS.

Basal Anti Mullerian hormone levels and endometrial thickness at midcycle can predict the outcome after clomiphene citrate stimulation in anovulatory women with PCOS, a retrospective study

Purpose

Recent studies reported that in polycystic ovary syndrome (PCOS) patients, other stimulation agents are superior to the popular first-line regimen, clomiphene citrate (CC) for ovarian stimulation. Nonetheless, CC is still widely used since it is not clear which patients will not respond to it. Furthermore, the prognostic value of endometrium thickness at midcycle is controversial. We aimed to find factors predicting the response to CC and the prognostic value of endometrial thickness at midcycle.

Methods

We collected data retrospectively from 89 anovulatory PCOS patients who had the first stimulation with 50 mg CC. We analyzed the basal levels of AMH, testosterone, LH, LH:FSH ratio and the endometrial thickness at midcycle by univariate, followed by multivariate regression. The outcome measures were pregnancy, follicle maturation and endometrial thickness at midcycle.

Results

Stimulation with 50 mg CC resulted in follicle maturation in 50.6% of the women and in 27.0% pregnancies. In the univariate analysis, greater endometrial thickness, lower LH and AMH levels and a lower LH:FSH ratio were associated with pregnancy (p < 0.05). In the multivariate analysis, only endometrial thickness remained predictive (p = 0.045). The endometrial thickness cutoff level of ≥ 8 mm showed a sensitivity of 87.5% (96% CI 67.6–97.3) and a specificity of 66.7% (95% CI 43.0–85.4) for prediction of pregnancy. In the multivariate analysis AMH levels 5.4 (3.4; 7.0) (ng/mL) predicted pregnancy (β = − 0.194 ± 0.092; p = 0.034)

Conclusion

We suggest to refrain from CC as first-line regimen in patients with AMH > 7 ng/ml. Under CC treatment, the cutoff value of ≥ 8 mm endometrium thickness at midcycle is associated with a better outcome.

The Prevalence of Incidental Endometriosis in Women Undergoing Laparoscopic Ovarian Drilling for Clomiphene-Resistant Polycystic Ovary Syndrome: A Retrospective Cohort Study and Meta-Analysis

To evaluate the incidence of endometriosis in polycystic ovary syndrome (PCOS) patients who did not present with any endometriosis symptoms and underwent laparoscopic ovarian drilling (LOD) for clomiphene citrate (CC) resistance, 225 and 630 women with CC-resistant PCOS without classic endometriosis symptoms were included in a retrospective study and a meta-analysis, respectively. All women underwent LOD. The main outcome parameter was the prevalence of incidental endometriosis. Laparoscopy revealed endometriosis in 38/225 (16.9%) women (revised American Fertility Society (rAFS) stage I: 33/38, 86.8%; rAFS stage II: 5/38, 13.2%). When women with CC-resistant PCOS without endometriosis were compared, lower body mass index (BMI) and lower 25-hydroxy-vitamin D levels were associated with the presence of endometriosis at laparoscopy (odds ratios (OR): 0.872, 95% confidence intervals (95%CI): 0.792–0.960; p = 0.005 and OR: 0.980, 95%CI: 0.962–0.999; p = 0.036; respectively). The inclusion criteria for the meta-analysis were fulfilled by 4/230 reports about LOD. After correction for study heterogeneity, the pooled prevalence of incidental endometriosis was 7.7% in women with CC-resistant PCOS. In conclusion, the rate of incidental endometriosis in women with CC-resistant PCOS might reflect the prevalence of asymptomatic endometriosis. All cases were affected by minimal or mild disease. Since the literature lacks reports on associated clinical outcomes, the relevance of this entity in such patients should be the subject of further studies.

Errors in search strategies used in systematic reviews and their effects on information retrieval

Objectives

Errors in search strategies negatively affect the quality and validity of systematic reviews. The primary objective of this study was to evaluate searches performed in MEDLINE/PubMed to identify errors and determine their effects on information retrieval.

Methods

A PubMed search was conducted using the systematic review filter to identify articles that were published in January of 2018. Systematic reviews or meta-analyses were selected from a systematic search for literature containing reproducible and explicit search strategies in MEDLINE/PubMed. Data were extracted from these studies related to ten types of errors and to the terms and phrases search modes.

Results

The study included 137 systematic reviews in which the number of search strategies containing some type of error was very high (92.7%). Errors that affected recall were the most frequent (78.1%), and the most common search errors involved missing terms in both natural language and controlled language and those related to Medical Subject Headings (MeSH) search terms and the non-retrieval of their more specific terms.

Conclusions

To improve the quality of searches and avoid errors, it is essential to plan the search strategy carefully, which includes consulting the MeSH database to identify the concepts and choose all appropriate terms, both descriptors and synonyms, and combining search techniques in the free-text and controlled-language fields, truncating the terms appropriately to retrieve all their variants.

Pharmacology of medications used for ovarian stimulation

Medications to stimulate the ovaries may be used to induce ovulation in patients with anovulatory infertility or to hyperstimulate the ovaries in a controlled fashion in ovulatory patients as part of assisted reproductive treatments (ART). The pharmacology of all current major medications used to stimulate ovarian function is reviewed in this article, including letrozole, clomiphene citrate, gonadotropins, and pulsatile gonadotropin releasing hormone (GnRH). Novel potential compounds and adjuvant treatment approaches are also discussed, such as kisspeptin agonists and androgens.

Prolonged blastomere movement induced by the delay of pronuclear fading and first cell division adversely affects pregnancy outcomes after fresh embryo transfer on Day 2: a time-lapse study

RESEARCH QUESTION

What is the incidence, origin and clinical significance of blastomere movement after the first cell division in the human embryo?

DESIGN

A total of 1096 embryos, cultured in the EmbryoScope+ ® time-lapse system and subjected to a single fresh cleaved embryo transfer, were retrospectively analysed. Type and duration of blastomere movement (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov during the 2-cell stage [dBMov/(t3-t2)] was calculated. Morphological evaluation of embryos was performed by referring to the size of the blastomere and fragmentation after first division in addition to Veeck's criteria on Day 2. The correlation between dBMov and ongoing pregnancy was evaluated and the association of dBMov with patient and embryonic characteristics was determined.

RESULTS

Both movement type and the value of dBMov/(t3-t2) were significantly associated with asymmetrical first division, fragment formation and morphological grade on Day 2. Multivariate logistic regression analysis revealed that a higher value of dBMov/(t3-t2) significantly correlated with a decreased ongoing pregnancy rate, even after adjustment for co-founders (odds ratio 0.399, P = 0.0419). The time intervals of pronuclear (PN) alignment and PN fading were significantly correlated with the dBMov/(t3-t2) value.

CONCLUSIONS

Embryos with extended blastomere movement after the first cell division, which is associated with the delay of PN fading and first cell division, have a lower competence to initiate an ongoing pregnancy after fresh embryo transfer on Day 2. Thus, blastomere movement could be a useful predictive parameter for selecting embryos at the early cleavage stage.

Comparison of pregnancy outcomes following fresh and electively frozen single blastocyst transfer in natural cycle and clomiphene-stimulated IVF cycles

STUDY QUESTION

Are there any differences in live birth rates (LBR) following fresh blastocyst transfer in natural or clomiphene-stimulated cycles, or after elective blastocyst freezing in clomiphene-stimulated cycles followed by thawing and transfer at different time-points?

SUMMARY ANSWER

Clomiphene citrate (CC) administration adversely affected the LBR after single fresh blastocyst transfer (SBT) in CC cycles compared with that in natural cycles, while this adverse effect of CC is not present when a single vitrified-warmed blastocyst transfer (SVBT) is performed in subsequent natural ovulatory cycles, regardless of the duration between CC administration and the day of SVBT.

WHAT IS KNOWN ALREADY

CC affects uterine receptivity associated with a thinning of the uterine endometrium through an antioestrogenic effect. However, the duration that this adverse effect of CC on uterine endometrium persists after initial use is still unknown.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 157 natural cycle IVFs followed by SBT and 1496 minimal ovarian stimulation with CC IVF cycles followed by SBT (n = 24) or SVBT (n = 1472) from January 2010 to December 2014 was conducted. SVBT cycles were classified into two groups according to the period between the last day of CC administration and the day of SVBT (A: ≤60 d and B: ≥61 d). All groups were then compared based on pregnancy outcomes (natural-SBT group: n = 157, CC-SBT group: n = 24, SVBT-A: n = 1143, SVBT-B: n = 329).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women were aged 30–39 years at oocyte retrieval. In SVBT cycles, blastocysts were vitrified and warmed using a Cryotop safety kit. SVBT was performed in subsequent natural ovulatory cycles. The main outcomes were LBR and neonatal outcome, and both were compared among the groups.

MAIN RESULTS AND THE ROLE OF CHANCE

The LBR in the CC-SBT group (29.2%, 7/24) was significantly lower compared with the natural-SBT (56.1%, 88/157) (P = 0.01) and SVBT-A (50.0%, 572/1143) (P = 0.04), but not SVBT-B (47.4%, 156/329), groups. Furthermore, multivariate logistic regression analysis revealed that the LBR was comparable among the natural-SBT and SVBT groups, but was significantly lower in the CC-SBT group (adjusted odds ratio: 0.324, 95% CI: 0.119–0.800, P = 0.01). No significant differences among all groups were observed for gestational age (P = 0.19), birthweight (P = 0.41) and incidence of malformation (P = 0.53).

LIMITATIONS, REASONS FOR CAUTION

In this study we analysed a biased sample, based on clinical judgement regarding endometrial thickness, and the study was limited by its retrospective nature. The low statistical power caused by the group size disparity was also a limitation, especially in the CC-SBT group. Although the outcome showing inferiority of CC-SBT compared to natural-SBT is consistent with general findings in the literature, further large-scale clinical studies, ideally RCTs, are necessary to validate our results and clarify the prolonged effect of CC in SVBT cycles on pregnancy and neonatal outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

Our observation suggests that CC administered in minimal ovarian stimulation cycles affects adversely the pregnancy outcomes when SBT is performed. Therefore, for a CC-based minimal stimulation IVF cycle, we suggest that frozen embryo transfer should be performed in a subsequent natural ovulatory cycle to avoid the possibility of implantation failure associated with CC administration.

STUDY FUNDING/COMPETING INTERESTS

The authors have no conflicts of interest to declare. No external funding was either sought or obtained.