Associations of Maternal Vitamin D Deficiency with Pregnancy and Neonatal Complications in Developing Countries: A Systematic Review

Abstract

Pregnant women in Asia, the Middle East, Africa and Latin America are at risk of vitamin D deficiency (VDD) and prevalence throughout these regions are among the highest, globally. Maternal VDD has been associated with increased risk of a number of adverse maternal and neonatal health outcomes, yet research from developing countries is limited. We assessed the associations of maternal VDD during pregnancy with adverse health outcomes by synthesizing the literature from observational studies conducted in developing countries. Six electronic databases were searched for English-language studies published between 2000 and 2017. Thirteen studies from seven countries were included in the review. Prevalence of VDD ranged from 51.3% to 100%. Six studies assessed both maternal and neonatal outcomes, four studies assessed only maternal outcomes and three studies assessed only neonatal outcomes. Ten studies showed at least one significant association between VDD and adverse maternal and/or neonatal health outcomes including pre-eclampsia (n = 3), gestational diabetes mellitus (n = 1), postpartum depression (n = 1), emergency cesarean section delivery (n = 1), low birth weight babies (n = 4), small for gestational age (n = 2), stunting (n = 1). However most of these studies (n = 6) also showed no association with multiple health outcomes. Vitamin D assessment methods, criteria applied to define VDD, season and trimester in which studies were conducted varied considerably across studies. In conclusion, this study highlights the need to improve maternal vitamin D status in developing countries in an effort to support best maternal and child health outcomes across these regions. Future research should focus on more unified approaches to vitamin D assessment and preventative approaches that may be embedded into already existing antenatal care settings.

Maternal and neonatal vitamin D status at birth in black South Africans

“…[1,2] Maternal vitamin D deficiency (VDD) has been associated with an increased risk of adverse maternal and neonatal outcomes. [3] The fetus is entirely dependent on transplacental acquisition of maternal 25-hydroxyvitamin D (25(OH)D) to main tain its vitamin D status, so neonatal vitamin D status at birth is directly related to maternal status. Vitamin D is a prohormone that is either ingested or produced in the skin from 7-dehydrocholesterol through the influence of ultraviolet B (UVB) radiation.…”

Maternal Vitamin D Status among Different Ethnic Groups and Its Potential Contribution to Adverse Pregnancy and Child Outcomes

“…Systematic reviews and meta-analysis, including cross-sectional, longitudinal, cohort, ecological, and observational studies, indicate inconsistent results regarding the association between vitamin D deficiency and PET. Some studies reported an increased risk of PET women with vitamin D deficiency in pregnancy in contrast with others [43][44][45]. This contradiction of finding can be explained by different vitamin D assessment methods, criteria applied to define vitamin D deficiency, different season and trimester in studies [44].…”

“…Some studies reported an increased risk of PET women with vitamin D deficiency in pregnancy in contrast with others [43][44][45]. This contradiction of finding can be explained by different vitamin D assessment methods, criteria applied to define vitamin D deficiency, different season and trimester in studies [44]. Therefore, associations are inconclusive, often contradictory, confounded, and lack causality.…”

“…In contrast, some studies indicate no association [60,61], and even increased risk of PPD with sufficient vitamin D concentrations (≥50 nmol/L) [62]. However, in a systematic review study, a few studies reported the role of vitamin D in this pregnancy outcome [44]. Thus, although postpartum depression might be associated with vitamin D deficiency, inconsistent results need for more extensive studies in this regard.…”

“…Conflicting results have been found in case-control, prospective cohort studies, and reviews looking into the risk of GDM with vitamin D status [46]. Some review studies indicate that pregnant women with significant lower 25(OH)D had a higher risk of GDM by 40-60% [45,52], while in systematic and critical reviews, most studies failed to support the association between vitamin D status and GDM prevention [43,44]. Thus, more large-scale prospective studies are needed to evaluate this association.…”