Context: Vitamin D is associated with a host of reproductive outcomes, but there is little research investigating these relationships in healthy, regularly cycling, premenopausal women.Objective: Our objective was to assess the relationship between vitamin D and hormonal biomarkers, sporadic anovulation, menstrual cycle length, and premenstrual syndrome and its symptoms. We hypothesize that vitamin D will be inversely associated with aberrations in reproductive and gynecologic function.Methods: This was a prospective cohort of 1191 participants attempting to conceive, aged 18-40, with 1-2 prior pregnancy losses, no history of infertility, and enrolled in the EAGeR trial. Patients answered questionnaires regarding demographic information and gynecologic histories and serum samples were collected pre-randomization. Patients collected and froze daily first-void urine samples for up to two menstrual cycles. Patients were followed for risk of anovulation for two menstrual cycles and followed all together for up to six menstrual cycles.Results: Vitamin D was associated with free androgen index and sex hormone binding globulin concentration, but not total testosterone, free testosterone, or dehydroepiandrosterone sulfate. Vitamin D was negatively associated with estrone-1-glucoronide in urine but not with pregnanediol glucuronide. Vitamin D was not associated with menstrual cycle length or its phase components and was not associated with risk of sporadic anovulation. Vitamin D was associated with breast tenderness/fullness and generalized aches and pains during the premenstrual week but not with other symptoms or overall risk of PMS.Conclusions: Vitamin D may play a role in a host of reproductive and endocrine outcomes, including the bioavailability of androgens, concentrations of estrogens, and physical symptoms of PMS.
Vitamin D and menstrual cycle length in women with proven fecundity
