01 Jun 2018 --- Vitamin D may play a key protective role in healthy pregnancies, an analysis by researchers at the US National Institutes of Health (NIH) has shown. In a study published in The Lancet Diabetes & Endocrinology, the researchers note that among women planning to conceive after a pregnancy loss, those who had sufficient levels of vitamin D were more likely to become pregnant and have a live birth, compared to women with insufficient levels of the vitamin.