Vitamin D and the risk of preeclampsia - a nested case-control study

We aimed to determine the relation between vitamin D deficiency in early pregnancy and preeclampsia. In a nested case-control study of 2496 pregnant women, we identified 39 women who developed preeclampsia and 120 non-preeclamptic controls. Blood was sampled in 12th gestational week and analyzed for serum vitamin D. Vitamin D levels were similar in women who developed preeclampsia, 52.2 +/- 20.5nmol/L, and controls, 48.6 +/- 20.5nmol/L, p=0.3. In addition, vitamin D deficiency (<50nmol/L) was found in a similar proportion of control group (51.7%) as those with severe preeclampsia (41.2%). Women with vitamin D deficiency were 3cm shorter than those with normal vitamin D levels (p=0.002). Our data do not support the hypothesis that vitamin D deficiency in early pregnancy is associated with preeclampsia, but we cannot rule out a relation later in gestation.