ABSTRACT
PURPOSE: The aim of this study was to assess the effect of vitamin D supplementation on ovulation rate in overweight subfertile women with PCOS undergoing ovulation induction. METHODS: This was a single center, parallel-groups, double-blind, and placebo-controlled randomized trial involving 186 eligible women undergoing induction of ovulation with clomiphene citrate (Clomid®, Aventis) 50 mg tablet twice daily starting from the third day of menstrual cycle and for 5 days combined with either oral Vitamin D (ossofortin®, EVA PHARMA) 10,000 IU twice weekly and calcium (calciprex®, Marcyrl Pharmaceutical Industries) 1250 mg twice daily or to receive a placebo with calcium for three successive induction cycles. The vitamin D or placebo supplementation started 1 month before induction cycles (total four cycles). Cycles were monitored with ultrasound follicle tracking and mid-luteal serum progesterone measurement. The primary outcome was the ovulation rate after three induction cycles. RESULTS: The study was performed during the period between January 2018 and September 2018, Eighty six (92.5%) women in the treatment group and 73 (78.5%) in the control group had successful ovulation (p = 0.007). The absolute and relative risk reduction was 14% and 65% respectively. Biochemical and clinical pregnancy occurred in 61.3 and 50.5% in the treatment group, and in 49.5 and 39.8% in the control group (p = 0.105 and 0.141 respectively). CONCLUSION: In subfertile women with PCOS undergoing induction of ovulation, vitamin D supplementation significantly improved the ovulation rate; however, there was no effect on clinical or biochemical pregnancy.
