Pregnant woman caressing her bellyVitamin D status may be related to the tendency to develop diabetes during pregnancy, according to a study published in the Journal of Obstetrics and Gynecologic and Neonatal Nursing (volume 41, Issue 3, pages 328–338, May/June 2012). This was a meta-analysis that looked at six studies performed between 1999 and 2011. Five of the studies showed an inverse relationship between vitamin D levels and tests indicating a tendency toward gestational diabetes. One study did not actually look at the relationship between vitamin D levels and gestational diabetes, but did find that high vitamin D levels corresponded with lower blood sugar and insulin levels. Do not supplement yourself during pregnancy without advice from your physician. Getting some natural sunlight (careful not to burn) is one way to increase vitamin D levels.