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.

Key Points Question Is there an association between prenatal prescription opioid exposure and the risk of major and minor congenital malformations? Findings In this cohort study of 12 424 pregnancies, 891 women were dispensed prescription opioids during pregnancy. Opioid exposure in trimester 1 was not associated with major birth defects, but women dispensed opioids in trimester 3 had higher risks of offspring with minor birth defects in the musculoskeletal system. Meaning The study findings suggest a higher risk of minor congenital malformations in the musculoskeletal system that is associated with prenatal prescription opioid exposure in the third trimester; this risk appears to be dose-dependent.

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