MATERNAL VITAMIN D STATUS AND RISK OF PREECLAMPSIA
Hypertension in pregnancy is one of the leading causes of maternal mortality and morbidity in the world. Also, vitamin D deficiency is very common in pregnancy with up to 50% of individuals classified as vitamin D deficient. Primary prevention of pre- eclampsia has been a subject of active research as the exact aetiology is still unknown. Epidemiological and clinical studies have shown that vitamin D deficiency might be a risk factor for adverse foeto-maternal outcomes like pre-eclampsia, pre-term labour, low birthweight and intrauterine growth restriction. Vitamin D is therefore critical for maternal health and favourable maternal and foetal outcomes.
This study aimed to assess and compare serum 25-hydroxyvitamin D3 [25(OH)D3] concentrations in preeclamptic and normotensive pregnant women.
Materials and methods
This was a cross sectional comparative study involving women attending antenatal clinics or admitted for delivery in the maternity and labour wards of the University of Abuja Teaching Hospital, Abuja. One hundred and ten (110) of them were enrolled. A proforma was used to obtain data. Data to be obtained include sociodemographic characteristics, information regarding vitamin and mineral support during gestation, clothing style and duration of exposure to sun light. Non-fasting blood samples were collected at times of usual phlebotomy. ELISA method was used for evaluation of vitamin D status of the subjects utilizing serum specimens. The independent t-test was used for comparing continuous variables while chi-square test and Fishers exact test were used for comparing categorical data between the two groups. Logistic regression was used for multivariable adjustments. P value < 0.05 was considered statistically significant.
Overall, the mean serum vitamin D (VD) level in the study population was 38.98ng/ml with a range of 14.10-83.50ng/ml. The prevalence of VD deficiency in the population was 15%, while 16.8% and 68.2% of the participants had insufficient and normal levels respectively. The prevalence of VD deficiency in the preeclamptic group was 20.4% while
that in healthy pregnant women was 9.4% (p=0.189). The mean serum 25-OH-D level of women with pre-eclampsia was significantly lower when compared to that of the healthy women (34.5±14.9 vs. 43.5±15.1, P = 0.003). Comparison of women who were either deficient or insufficient revealed a statistically significant difference in gestational age at delivery (33.6±2.4 vs. 37.7±2.8, p=0.001) and their mean serum VD levels (16.52±1.63 vs. 24.99±2.13, p=<0.0001). The two groups were similar in all other variables. In the adjusted analysis of cases that were vitamin D deficient, there was almost a threefold odds of developing preeclampsia however, this was not statistically significantly [odds ratio (OR) = 3.27, CI = 0.99-10.83, P = 0.053]. On the other hand however, the odds of developing preeclampsia in women with Vitamin D insufficiency was strengthened, also resulting in more than a three- fold odds of developing preeclampsia. This was statististically significant (OR = 3.20, CI = 1.02–10.06, P = 0.046).
In conclusion, an association between vitamin D deficiency and preeclampsia was not demonstrated in this study. The results however suggest that maternal vitamin D insufficiency in late pregnancy is an independent risk factor for preeclampsia.