Effects of vitamin D supplementation on metabolic parameters of women with polycystic ovary syndrome: a meta-analysis of randomized controlled trials.

OBJECTIVE: The purpose of this meta-analysis was to evaluate the effects of vitamin D supplementation on metabolic parameters of women with polycystic ovary syndrome (PCOS). METHODS: We performed a literature search of databases and identified randomized controlled trials (RCTs) published prior to December 2019. A meta-analysis was conducted using RevMan 5.3 and Stata 12.0 software. We compared the effects of vitamin D supplementation alone to the administration of placebos on metabolic parameters of PCOS women with vitamin D deficiency. RESULTS: Ten articles of RCTs were included and analyzed in this meta-analysis, which included a total of 520 PCOS women. Our meta-analysis results showed no significant effects of vitamin D supplementation on BMI (p = .43), systolic blood pressure (p = .05), diastolic blood pressure (p = .87), fasting insulin concentration (p = .86), HOMA-IR (p = .47), HDL-C (p = .76), LDL-C (p = .23) and triglyceride (p = .77). Both low dose vitamin D supplementation (<4000 IU/day) and high dose vitamin D supplementation (≥4000 IU/day) were found to significantly decreased the fasting glucose concentration (p = .01, p = .001, respectively). Vitamin D supplementation significantly decreased total cholesterol concentration (p = .03). CONCLUSIONS: The results of this meta-analysis suggested that vitamin D supplementation decreases fasting glucose concentration and total cholesterol concentration in PCOS women with vitamin D deficiency.

Comparison of endometrial receptivity of clomiphene citrate versus letrozole in women with polycystic ovary syndrome: a randomized controlled study.

The aim of the study was to compare the effect of clomiphene citrate (CC) and letrozole on endometrial receptivity for ovulation induction in women with polycystic ovary syndrome (PCOS). A randomized controlled study included 160 patients diagnosed with PCOS, out of which 80 patients received 50 mg of CC and 80 patients received 2.5 mg of letrozole for successful ovulation induction. Endometrial thickness and pattern, the blood flow of uterine artery and subendometrial region, endometrial volume and vascularization index were measured. The ratio of multilayered endometrial pattern in letrozole group was significantly increased on the day of human chorionic gonadotropin (hCG) administration compared with CC group (77.5% vs. 55.0%). The volume, vascularization index (VI), flow index (FI), and vascularization flow index (VFI) of endometrium on the day of hCG administration and 7-9 days after ovulation in letrozole group were significantly increased. The biochemical pregnancy rate, clinical pregnancy rate, and ongoing pregnancy rate in letrozole group were significantly increased compared with CC group (36.3%, 30.0%, 22.5% vs. 21.3%, 13.8%, 10.0%, respectively). Letrozole increased pregnancy rates by improving endometrial receptivity compared with CC in patients with PCOS.