In this study, we assessed the prevalence of vitamin D deficiency in normotensive pregnant women and preeclamptic women in Ghana. The overall prevalence of vitamin D deficiency among the entire study participants was 81.7%. The prevalence in the preeclamptic women was 88.6%, whereas the normotensive pregnant women had a prevalence of 75.0%.
The high prevalence of vitamin D deficiency observed in the pregnant women in this study is similar to the observations made in other studies [3, 17, 21]. In a cross-sectional study among Saudi Arabian pregnant women, Al-Faris et al., observed a prevalence of over 90% . Choi et al.,  also reported the prevalence of vitamin D deficiency in pregnant Korean women to be 77.3%. In one retrospective Chinese study by Song and co-workers  a prevalence of 90% vitamin D deficiency was reported. On the contrary, Bärebring et al.,  revealed the prevalence of vitamin D deficiency among pregnant women in Sweden as 10% in the entire population; 2% among women born in North Europe; and 50% among women born in Africa. On the contrary, however, S Hashemipour, N Esmailzadehha, A Ziaee, MH Khoeiniha, E Darvishgoftar, Z Mesgari, F Pashazade and S Abotorabi  observed no difference in vitamin D levels between preeclamptic women and the normotensive pregnant women in Iran. The differences in the findings of these studies could be attributed to the lack of uniformity in the cut-offs used to define vitamin D deficiency in the various studies, seasonal changes, diet, race, geographical location and use of vitamin D supplements . Although pregnant women in Ghana are prescribed the daily recommended allowance of folic acid and other hematinic medicines, the use and prescription of vitamin D supplements is not a common practice especially for pregnant women. It has for a long time been thought that the abundance of sunshine in the tropics provides adequate vitamin D. However, our study provides evidence that among both normotensive and preeclamptic women, vitamin D adequacy maybe a health problem worth giving attention to by policymakers.
Although, several factors affect vitamin D synthesis in the body [8, 9, 14], the skin is thought to represent the major source of vitamin D especially in the tropics. The observed high vitamin D deficiency in the present study suggests that vitamin D status might not mainly be dependent on exposure of the skin to sunlight; other factors such as diet, nutritional supplements and underlying health conditions may play essential roles, especially in the sub-Saharan African population where sunshine is in abundance. We have earlier reported a high prevalence of vitamin D deficiency among diabetics and among pre- and post-menopausal women [25, 26]. This present study accentuates the high prevalence of vitamin D deficiency not only among pregnant women but likely among the general populace.
Furthermore, our study demonstrates that higher proportion of the preeclamptic pregnant women with vitamin D deficiency presented with low-birth-weight neonates, IUGR and preterm delivery than women with vitamin D sufficiency. Vitamin D interacts with calcium and parathyroid hormone to influence foetal growth and development . Some studies have reported a significant association between low-birth-weight neonates and maternal vitamin D deficiency [27, 28]. Reports indicate that about 15 million infants worldwide are born preterm . Oluwole and co-workers demonstrated that pregnant women with vitamin D deficiency have an approximately 9-fold higher likelihood of preterm delivery . Similarly, Kalok  observed a significant correlation between vitamin D level and gestational age at delivery.
A healthy pregnancy is associated with physiologic hyperlipidemia to satisfy the demands of the developing foetus[32, 33]. Hyperlipidaemia in normal pregnancy is non-atherogenic, and attributed to hormonal changes. However, in preeclampsia, there is dysregulation of lipid metabolism, which manifests as abnormal maternal serum lipid levels [32–34]. Consistent with this study, several other studies have reported dyslipidaemia in preeclampsia and stated that abnormal lipid levels in pregnancy significantly contribute to the development of preeclampsia through the excessive deposition of triglycerides in the uterine spiral arteries which may result in endothelial dysfunction through the production of small dense LDL [32–36]. Although the women with preeclampsia in this study presented with abnormal serum lipid, no significant association between vitamin D deficiency and lipid was observed in both the normotensive women and preeclamptic women after adjusting for possible confounders. This may suggest that in this category of women, vitamin D status may not influence atherogenic risk. Other studies however,[37, 38] report significant association between vitamin D deficiency and lipids. It is noteworthy that in these studies, samples were collected in the first trimester and among normotensive pregnant women.
The present study was conducted only in the southern part of Ghana. Further studies are necessary across the country and with a larger sample size. More so dietary recall was not possible in this study.