Association between Vitamin D and pregnancy in women with polycystic ovary syndrome: a cohort study from Beijing, China

Abstract

Abstract Background Polycystic ovary syndrome (PCOS) is one of the most common gynecological endocrine diseases, and one of the primary causes of anovulatory infertility. Vitamin D deficiency is common in PCOS patients, but few studies have been done on the relationship between vitamin D and reproductive function in PCOS patients. We investigate the correlation between vitamin D levels and pregnancy in patients with PCOS after ovulation induction therapy to explore the role of vitamin D in PCOS. Methods We enrolled a total of 200 newly diagnosed infertile patients with PCOS (experimental group) and 200 healthy women of childbearing age (control group) between June 2016 and September 2018. We investigated the pregnancy rate for patients with PCOS and studied correlation of pregnancy rate and levels of 25-(OH) D3 in patients with PCOS. Then we evaluated serum 25-(OH) D3 levels between the two subgroups, with the experimental group divided into vitamin D-deficient and vitamin D non-deficient subgroups and analyzed their respective pregnancy rates. Results The mean serum 25-(OH) D3 level in the experimental group was significantly lower than that in the control group (14.57 ± 5.86 ng/mL vs. 22.24 ± 6.73 ng/mL, respectively; t = 12.190, P < 0.05). Of the 200 patients in the experimental group, 149 patients completed the ovulation-induction regimen, comprising 72 patients who became pregnant and 77 patients who failed to become pregnant—generating a pregnancy rate of 48.32%. We noted that the serum 25-(OH) D3 level in the pregnant patients was significantly higher than that in the non-pregnant patients (16.06 ± 5.80 ng/mL vs. 13.54 ± 5.88 ng/mL, respectively; t = 2.635, P < 0.05). Additionally, the pregnancy rate was 43.89% in the vitamin D-deficient group compared to 67.86% in the vitamin D non-deficient group, with the latter significantly higher compared to the former group (χ2 = 5.269, P < 0.05). Conclusions The serum vitamin D level, was lower in the PCOS patients than in healthy women, and the pregnant PCOS patients undergoing ovulation induction exhibited a higher level than non-pregnant patients. Our results indicated a positive role for vitamin D in pregnant patients with PCOS. We demonstrated that vitamin D appeared to play a beneficial role in PCOS patients undergoing an ovulation-induction regimen. We posit that vitamin D may in the future serve as an indicator to guide the clinical treatment of PCOS patients of child-bearing age.