Vitamin D deficiency during pregnancy is associated with adverse pregnancy outcomes, although the association between preconception vitamin D concentrations and livebirth is unknown.

The study aimed to assess the association between preconception vitamin D and pregnancy outcomes among women with proven fecundity.

The findings were published in The Lancet Diabetes & Endocrinology and 1191 women had available data on preconception 25-hydroxyvitamin D concentrations.

According to the study sufficient preconception 25-hydroxyvitamin D (≥75 nmol/L) was associated with increased likelihood of pregnancy and livebirth. Increased vitamin D concentrations before conception, but not in early pregnancy, were associated with reduced pregnancy loss.