Among women planning to conceive after a pregnancy loss, sufficient preconception levels of vitamin D was associated with increased likelihood of pregnancy and live birth, compared to women with insufficient levels of the vitamin. Researchers performed a secondary analysis of the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial, which sought to determine if daily low-dose aspirin (81 mg) could prevent miscarriage in women with a history of pregnancy loss. Blood levels of vitamin D were tested for ~1,200 women aged 18 to 40 years before pregnancy and again at the eighth week of pregnancy. They found:

• Women who had sufficient preconception vitamin D concentrations were 10% more likely to become pregnancy and 15% more likely to have a live birth.
• Among women who became pregnancy, each 10 nanogram per milliliter increase in preconception vitamin D was associated with a 12% lower risk of pregnancy loss.
• Vitamin D levels in the eighth week of pregnancy were not linked to pregnancy loss.