High prevalence of vitamin D deficiency among normotensive and hypertensive pregnant women in Ghana.

Background: Hypovitaminosis D in pregnancy is associated with adverse health outcomes in mothers, newborns and infants. This study assessed the levels of 25-hydroxyvitamin D [25(OH)D] in normotensive pregnancies and in preeclampsia, evaluated the association between vitamin D deficiency and preeclampsia risk; and determined the foeto-maternal outcome in preeclamptic women with vitamin D deficiency.

Methods: This case-control study was conducted among pregnant women who visited the Comboni Hospital, in Ghana from January 2017 to May 2018 for antenatal care. A total of 180 pregnant women comprising 88 preeclamptic women (PE) and 92 healthy normotensive pregnant women (NP) were recruited. Socio-demographic, clinical and obstetric data were obtained using validated questionnaires. Blood pressure and anthropometrics were measured, and blood samples were collected for the estimation of 25- hydroxyvitamin D [25(OH)D] using enzyme-linked immunosorbent assay technique. Lipids (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol) were also estimated.

Results: A total of 81.7% of the study participants had vitamin D deficiency. Of these, 88.6% of the women with PE had vitamin D deficiency compared to 75.0% in the NP. Vitamin D levels were significantly reduced in the PE women compared to the normotensive pregnant women (p = 0.001). A higher proportion of the preeclamptic women who were vitamin D deficient had preterm delivery (p < 0:0001) and delivered low birth weight infants (p < 0:0001), and infants with IUGR (p < 0:0001) compared to the control group (p < 0:0001). Pregnant women with PE presented with significant dyslipidemia, evidenced by significantly elevated TC (p = 0.008), LDL (p < 0.0001), triglycerides (p = 0.017) and a significantly reduced HDL (p = 0.001) as compared to NP. In the preeclamptic women, serum 25(OH) D showed an inverse, but not significant association with TC (β = - 0.043, p = 0.722, TG (β = - 0.144, p = 0.210) and LDL (β = - 0.076, p = 0.524) and a positive, but not significant association with HDL (β = 0.171, p = 0.156).

Conclusion: The prevalence of vitamin D deficiency is high in both normotensive pregnancies and pregnancies complicated by preeclampsia but amplified in preeclampsia. Higher proportion of pregnant women with hypovitaminosis D had preterm babies and delivered low birth weight neonates. Additional studies are needed to explore the potential benefits and optimal dosing of vitamin D use in pregnancy, especially in sub-Saharan Africa.