Vitamin D supplementation for women during pregnancy

• Published in: Cochrane database of systematic reviews 2019-07, Vol.7 (7), p.CD008873
• Main Authors: Palacios, Cristina, Kostiuk, Lia K, Peña-Rosas, Juan Pablo
• Format: Article
• Language: English
• Subjects: Calcium, Dietary - administration & dosage; Child health; Complementary & alternative medicine; Diabetes, Gestational - prevention & control; Dietary Supplements; Female; Humans; Nutrition during pregnancy; Pre-Eclampsia - prevention & control; Pregnancy; Pregnancy & childbirth; Pregnancy Complications - prevention & control; Pregnancy Outcome; Premature Birth - prevention & control; Randomized Controlled Trials as Topic; Vitamin D - administration & dosage; Vitamin D - analogs & derivatives; Vitamins - administration & dosage
• ISSN: 1469-493X; 1469-493X
• DOI: 10.1002/14651858.CD008873.pub4

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016. To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes. For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data. Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention. Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach. We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitam