Parameters for calcium metabolism in women with polycystic ovary syndrome who undergo clomiphene citrate stimulation: a prospective cohort study

Objective: To evaluate whether parameters for calcium metabolism were associated with characteristics of polycystic ovary syndrome (PCOS). Design: A prospective cohort study. Methods: Ninety-one anovulatory, infertile women with PCOS patients underwent clomiphene citrate (CC) stimulation. Main outcome measures were parathyroid hormone (PTH); 25-hydroxyvitamin D3 (25OHD3); serum levels of calcium, phosphorus, magnesium, albumin, and total protein; the serum calcium-phosphorus product; LH; FSH; sexual hormone binding globulin; testosterone; and androstenedione. Results: PTH correlated inversely with serum calcium (r=-0.235; P=0.004) and 25OHD3 (r=-0.664; P < 0.001), whereas positive correlations were found between PTH and body mass index (BMI; r=0.270; P=0.010) and between PTH and testosterone (r=0.347; P=0.001). After stimulation with 50 mg CC, 57.1% (52/91) developed a follicle, whereas 26.4% (24/91) became pregnant. In a multivariate model to predict both follicle development and pregnancy, BMI and 25OHD3 deficiency were significant predictive parameters. Conclusions: 25OHD3 deficiency was an independent predictive parameter of CC stimulation outcome, in terms of follicle development and pregnancy. Our results suggest a substantial role of vitamin D in PCOS and infertility treatment in these patients.