O-010 Vitamin D supplementation prior to in vitro fertilization in patients with polycystic ovary syndrome: a multicentre randomised double-blind placebo-controlled clinical trial

Abstract Study question Does vitamin D supplementation increase live birth rates in patients with polycystic ovary syndrome (PCOS) scheduled for IVF? Summary answer Vitamin D supplementation of 4,000 IU/day for around 12 weeks until the triggering day does not increase success rates in PCOS women scheduled for IVF. What is known already People with PCOS have a higher risk of fertilisation failure, biochemical pregnancy loss, and miscarriage compared to those without PCOS. Vitamin D deficiency is notably more prevalent in people with PCOS compared to those without PCOS. Vitamin D supplementation has shown inconsistent results in terms of its impact on pregnancy outcomes in patients with PCOS undergoing IVF. Study design, size, duration A multicenter, double-blinded, placebo-controlled, randomised trial was performed across 24 hospitals in China. Participants were recruited from October 2020 to February 2022. The primary outcome was live birth after the first embryo transfer. Secondary outcomes included serum 25-OHD levels on the day of triggering and other fertility outcomes following the first transfer. Participants/materials, setting, methods PCOS women scheduled for IVF were randomised to the vitamin D group (4,000 IU/day) or the placebo group for up to 12 weeks until the triggering day. The randomisation was stratified by centre. The intention-to-treat set was used as the primary analytical approach. For binary outcomes, a Poisson regression with robust variance estimate was used to calculate risk ratios and 95% confidence intervals (CIs). For continuous outcomes, the analysis of covariance (ANCOVA) approach was used. Main results and the role of chance Of 876 participants randomised, 865 were included in the final analysis, with 435 in the vitamin D group and 430 in the placebo group, respectively. Mean baseline serum 25-OHD levels were 16.5 and 16.1 ng/ml in the vitamin D and the placebo groups, respectively. On the day of triggering, the mean serum 25-OHD level was significantly higher in the vitamin D group than that in the placebo group (32.3 vs 18.2 ng/ml, adjusted mean difference 13.6 ng/ml, 95% CIs 10.9-16.3). There were 226 (52.0%) live births in the vitamin D group and 216 (50.2%) live births in the placebo group (adjusted RR 1.04, 95% CIs 0.91-1.18). There were no significant differences between the groups on other fertility outcomes following the first transfer, including ongoing pregnancy, clinical pregnancy, and positive pregnancy tests, and miscarriages. Limitations, reasons for caution Most participants had type C PCOS (anovulation and polycystic ovaries). The findings should be interpreted with caution in populations dominated by other types of PCOS. Wider implications of the findings While vitamin D supplementation 4000IU/day for up to 12 weeks significantly increases serum 25-OHD levels following the intervention, but this does not translate to improved live birth rates following the first transfer for patients with PCOS scheduled for IVF. Trial registration number Yes