Impact of vitamin D deficiency on phenotypes and IVF outcomes in PCOS: a prospective study

RESEARCH QUESTION: Does vitamin D deficiency affect phenotypes and pregnancy outcomes in women with polycystic ovary syndrome (PCOS) who are undergoing IVF/intracytoplasmic sperm injection (ICSI)? DESIGN: This prospective cohort study recruited 725 infertile women with PCOS undergoing IVF/ICSI at the Reproductive Center of Peking University Third Hospital. The participants were divided into two groups according to the serum vitamin D concentration: the vitamin D deficiency group (serum 25(OH)D <20 ng/ml, n = 491) and vitamin D non-deficiency group (serum 25(OH)D ≥20 ng/ml, n = 234). Measurements were made of serum hormone concentrations and parameters relating to lipid and glucose metabolism. Pregnancy outcomes were clinical pregnancy and early miscarriage. RESULTS: Serum concentrations of anti-Müllerian hormone (P = 0.042), testosterone (P = 0.035) and androstenedione (P = 0.016) were higher in the vitamin D deficiency group than the non-deficiency group. Vitamin D deficiency was still associated with increased androstenedione concentrations after adjustment for confounders (regression coefficient -0.851, 95% confidence interval [95% CI] -1.661 to -0.042, P = 0.039). No significant difference was found in parameters of lipid and glucose metabolism or in clinical pregnancy and early miscarriage rates between two groups. There was no correlation between vitamin D deficiency and clinical pregnancy (odds ratio [OR] 1.193, 95% CI 0.852-1.671, P = 0.303) or early miscarriage (OR 1.360, 95% CI 0.668-2.767, P = 0.397). CONCLUSIONS: Vitamin D deficiency is correlated with worse parameters, especially higher androstenedione concentrations in infertile women with PCOS. Vitamin D deficiency has no correlation with clinical pregnancy or early miscarriage in women with PCOS undergoing IVF/ICSI treatment.