Systematic review and meta-analysis of letrozole and clomiphene citrate in polycystic ovary syndrome

Strong Early Impact of Letrozole on Ovulation Induction Outperforms Clomiphene Citrate in Polycystic Ovary Syndrome

Polycystic ovary syndrome is a common endocrine disorder, characterized by hyperandrogenism and/or chronic oligo/anovulation, which leads to infertility. The aim of this systematic review and meta-analysis was to explore the efficacy of letrozole compared with clomiphene citrate for ovulation induction in women with polycystic ovarian syndrome. The study protocol has been registered with PROSPERO (registration number CRD42022376611). The literature search included randomized clinical trials. We conducted our systematic literature search across three medical databases: MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. The data synthesis employed a random effects model. Out of the 1994 articles screened, 25 studies fulfilled the inclusion criteria. The letrozole group exhibited a significant increase in endometrial thickness (mean difference = 1.70, confidence interval: 0.55-2.86; I2 = 97%, p-value = 0.008). The odds of ovulation (odds ratio = 1.8, confidence interval: 1.21-2.69; I2 = 51%, p-value = 0.010) and pregnancy (odds ratio = 1.96, confidence interval: 1.37-2.81; I2 = 32%, p-value = 0.002) were significantly higher. The resistance index of the subendometrial arteries showed a significant decrease (mean difference = -0.15, confidence interval: -0.27 to -0.04; I2 = 92%, p-value = 0.030). Women diagnosed with polycystic ovarian syndrome and treated with letrozole for ovulation induction had increased ovulation and pregnancy rates and increased endometrial thickness. The lower resistance index of subendometrial arteries can enhance intrauterine circulation, creating more favorable conditions for embryo implantation and development.

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.

The Value of Anti-Müllerian Hormone in Predicting Ovulation Induced by Aromatase Inhibitors in Women With Polycystic Ovary Syndrome

OBJECTIVES

This study aimed to evaluate the value of anti-Müllerian hormone (AMH) in predicting ovulation induced by aromatase inhibitors (AI) and pregnancy outcomes in women with polycystic ovary syndrome (PCOS).

METHODS

From January 2018 to December 2020, this prospective cohort study enrolled women with PCOS aged between 18 and 45 years who underwent ovulation induction using AI protocol and intrauterine insemination (IUI) for infertility at a Center for Reproductive Endocrinology and Infertility, University Hospital. Receiver operating characteristic curves were used to estimate the chance of ovulation responses and pregnancy outcomes.

RESULTS

In total, 64% of 65 women with PCOS were recruited following AI treatment, and the clinical pregnancy rate was 19.4% following IUI. Patients who experienced ovulation had a lower mean serum AMH concentration than non-responders (7.11 ng/mL vs. 8.95 ng/mL, respectively), but the difference was not statistically significant. Between the pregnancy and non-pregnancy groups, statistically significant differences in AMH concentrations were observed (8.71 ng/mL vs. 6.73 ng/mL, respectively, P = 0.040). The area under the curve of the receiver operating characteristic for non-ovulation prediction was 0.445, 95% CI (0.284-0.606) with P = 0.467, and for clinical pregnancy was 0.735, 95% CI (0.561-0.910) with P = 0.104.

CONCLUSIONS

In women with PCOS, the AMH level does not predict ovarian responsiveness to AI treatment, but it does predict the success of IUI cycles.

Electroacupuncture to Improve Endometrial Receptivity and Folliculogenesis in Polycystic Ovary Syndrome

Objective: Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting folliculogenesis and endometrial receptivity. PCOS causes low fertility due to failures in folliculogenesis and ovulation. Electroacupuncture (EA) may help improve folliculogenesis and endometrial receptivity. EA can decrease tonic activity in the sympathetic vasoconstrictor pathway to the uterus. This study was conducted to determine the effect of the addition of EA therapy on folliculogenesis and endometrial receptivity in women with PCOS. Materials and Methods: This case-control study was conducted at the Dr. Moewardi General Hospital, in Jawa Tengah, Indonesia. The subjects were women with PCOS, ages 20-45, who were infertile. They were divided into a control group (17 women) and an experimental group (17 women). The control group received letrozole therapy, and the experimental group received EA + letrozole therapy. Folliculogenesis is determined by measuring the growth of follicle diameter on days 2, 6, 8, 10, and 12 of the menstrual cycle. Endometrial receptivity is determined by resistance index (RI) and pulsatility index (PI) examinations on days 19 and 21; endometrial thickness is measured on day 12. Results: There was a significant difference in folliculogenesis on days 2, 6, 8, 10, and 12. Folliculogenesis with letrozole versus EA + letrozole, respectively, were: day 2 = 5.59 ± 1.06 versus 7.01 ± 1.53, P = 0.004; day 6 = 6.71 ± 1.59 versus 9.11 ± 1.23, P < 0.001; day 8 = 9.51 ± 2.68 versus 12.44 ± 1.49, P < 0.001; day 10 = 11.30 ± 3.08 versus 15.53 ± 2.34, P < 0.001; and day 12 = 13.92 ± 3.61 versus 19.86 ± 0.75, P < 0.001. RI value with letrozole versus EA + letrozole were, respectively, day 19 = 0.91 ± 0.07 versus 0.88 ± 0.07, P = 0.150; day 21 = 0.88 ± 0.07 versus 0.79 ± 0.09, P < 0.001. PI value with letrozole versus EA + letrozole were respectively, day 19 = 3.00 ± 0.89 versus 2.30 ± 0.65, P = 0.009; and day 21 = 2.72 ± 0.88 versus 2.02 ± 0.55, P = 0.009. Endometrial thickness with letrozole versus EA + letrozole were, respectively, day 12 = 6.95 ± 1.82 versus 8.22 ± 1.76, P = 0.005. Conclusions: The addition of EA to letrozole therapy improved folliculogenesis, RI, PI, and endometrial thickness in patients with PCOS. Further studies are needed to gain a better understanding of the dosage and timing of this therapy and its potential synergy with other current treatments.