A recent study found that among women who have had a previous pregnancy loss, vitamin D levels affected their likelihood of conceiving and carrying a child to term.
Miscarriages are spontaneous pregnancy losses. It is estimated that 15-25% of pregnancies end in miscarriage, 80% of which occur in the first trimester2. There is research suggesting that vitamin D deficiency can increase miscarriage risk.
In a recent study published in the Lancet Diabetes & Endocrinology, researchers from the National Institute for Health (NIH) investigated what might be considered “sufficient” vitamin D to reduce miscarriage risk.
They looked at data on 1191 women from across the United States (between the ages of 18-40) who had had one or two previous miscarriages. They collected data on their serum 25-hydroxyvitamin D levels (taken before pregnancy and again at eight weeks), time to pregnancy, pregnancy loss, and live births between 2007 and 2011. They also collected additional demographic and lifestyle data from a questionnaire.
They defined sufficient vitamin D as having serum concentrations equal to, or greater than 75 nmol/L. Of the women in the study, they found that 53% had serum vitamin D levels below 30 nmol/L, which was low enough to be considered vitamin D insufficient. Additionally, women with adequate vitamin D levels were 10% more likely to conceive and 15% more likely to have a live birth than women whose vitamin D levels were low before conception and during the first eight weeks of their pregnancy.
While the findings reported in this study suggest that vitamin D may play a role in promoting and sustaining a pregnancy, this study does not prove that vitamin D insufficiency prevents conception or causes miscarriages. Further research is required to determine the efficacy of vitamin D supplementation for reducing miscarriage risk as well as optimal vitamin D levels for healthy reproductive outcomes.
Written by Debra A. Kellen, PhD
(1) Mumford, S. L., Garbose, R. A., Kim, K., Kissell, K., Kuhr, D. L., Omosigho, U. R., … & Plowden, T. C. (2018). Association of preconception serum 25-hydroxyvitamin D concentrations with livebirth and pregnancy loss: a prospective cohort study. The Lancet Diabetes & Endocrinology. http://dx.doi.org/10.1016/ S2213-8587(18)30153-0
(2) Tovey, A. & Cannell, JJ. The relationship between vitamin D and miscarriages. The Vitamin D Council Blog & Newsletter, May 30, 2017.