The relationship of serum vitamin D with pre-eclampsia in the Iranian women.

Vitamin D deficiency may be a risk factor for negative outcome in pregnancy, such as pre-term labour, low birthweight, intrauterine growth retardation and gestational diabetes. This study aimed to evaluate the relationship between vitamin D and pre-eclampsia. This was a case-control study of 59 pre-eclamptic women and 59 healthy pregnant women selected in two hospitals in Ahvaz, Iran. Women with term singleton pregnancy, nulliparous and of reproductive age were selected. Venous blood samples (2 mL) were taken and the level of 25-dihydroxy vitamin D (25-OH-D) was measured. If the levels of 25-OH-D were less than 10 ng mL(-1), between 10 ng mL(-1) and 29 ng mL(-1) and more than 30 ng mL(-1), they were considered as indicating deficient, insufficient and normal 25-OH-D concentrations, respectively. The independent t-test, Mann-Whitney U-test, chi-square and logistic regression were used for analysing the data. Vitamin D deficiency was significantly higher in the pre-eclampsia group [odds ratio (OR) = 24.04, confidence interval (CI) = 2.10-274.8, P = 0.01]. Older women (30-35 years) were more likely to develop pre-eclampsia compared with the control group (OR = 10.36, CI = 2.18-49.09, P = 0.003). The results showed that women with body mass index (BMI) <20 were more likely to develop pre-eclampsia. The ages between 20 years and 30 years and normal BMI were not the risk factors for pre-eclampsia. Vitamin D deficiency has a statistically significant relationship with pre-eclampsia. It seems that the serum vitamin D levels are low in Iranian women because of their particular lifestyle and they may need more than 400 IU day(-1) vitamin D supplement during pregnancy.