Objective To evaluate the role of vitamin D intake and serum levels on conception of clinical pregnancy and live birth. Design Prospective cohort study. Setting Academic medical centers. Patient(s) Healthy, nulliparous women, age 18–39 years, and their male partners. Intervention(s) None. Main Outcome Measure(s) Clinical pregnancy and live birth were compared between those who did or did not meet the vitamin D estimated average requirement (EAR) intake (10 μg/d) and with serum 25-hydroxyvitamin D (25(OH)D) considered at risk for inadequacy or deficiency (<50 nmol/L) or sufficient (≥50 nmol/L). Result(s) Among 132 women, 37.1% did not meet the vitamin D EAR and 13.9% had serum levels at risk for inadequacy or deficiency. Clinical pregnancies were significantly higher among women who met the vitamin D EAR (67.5% vs. 49.0%) and with sufficient serum 25(OH)D (64.3% vs. 38.9%) compared with those who did not. Live births were higher among those who met the vitamin D EAR (59.0% vs. 40.0%). The adjusted odds ratio (AOR) of conceiving a clinical pregnancy was significantly higher among those who met the EAR (AOR = 2.26; 95% confidence interval [CI], 1.05–4.86) and had sufficient serum 25(OH)D (AOR = 3.37; 95% CI, 1.06–10.70). The associations were not significant after controlling for selected nutrients and dietary quality. Conclusion(s) Women with vitamin D intake below EAR and serum 25(OH)D levels at risk for inadequacy or deficiency may be less likely to conceive and might benefit from increased vitamin D intake to achieve adequacy. Clinical Trial Registration Number NCT00642590.
All Science Journal Classification (ASJC) codes
- Reproductive Medicine
- Obstetrics and Gynecology