Associations of Maternal Vitamin B12 Concentration in Pregnancy With the Risks of Preterm Birth and Low Birth Weight: A Systematic Review and Meta-Analysis of Individual Participant Data.

Abstract

Vitamin B12 (hereafter referred to as B12) deficiency in pregnancy is prevalent and has been associated with both lower birth weight (birth weight <2,500 g) and preterm birth (length of gestation <37 weeks). Nevertheless, current evidence is contradictory. We performed a systematic review and a meta-analysis of individual participant data to evaluate the associations of maternal serum or plasma B12 concentrations in pregnancy with offspring birth weight and length of gestation. Twenty-two eligible studies were identified (11,993 observations). Eighteen studies were included in the meta-analysis (11,216 observations). No linear association was observed between maternal B12 levels in pregnancy and birth weight, but B12 deficiency (<148 pmol/L) was associated with a higher risk of low birth weight in newborns (adjusted risk ratio = 1.15, 95% confidence interval (CI): 1.01, 1.31). There was a linear association between maternal levels of B12 and preterm birth (per each 1-standard-deviation increase in B12, adjusted risk ratio = 0.89, 95% CI: 0.82, 0.97). Accordingly, B12 deficiency was associated with a higher risk of preterm birth (adjusted risk ratio = 1.21, 95% CI: 0.99, 1.49). This finding supports the need for randomized controlled trials of vitamin B12 supplementation in pregnancy.

• Authors: Tormod Rogne, Myrte J Tielemans, Mary Foong-Fong Chong, Chittaranjan S Yajnik, Ghattu V Krishnaveni, Lucilla Poston, Vincent W V Jaddoe, Eric A P Steegers, Suyog Joshi, Yap-Seng Chong, Keith M Godfrey, Fabian Yap, Raquel Yahyaoui, Tinku Thomas, Gry Hay, Marije Hogeveen, Ahmet Demir, Ponnusamy Saravanan, Eva Skovlund, Marit P Martinussen, Geir W Jacobsen, Oscar H Franco, Michael B Bracken, Kari R Risnes
• Journal: American journal of epidemiology (Am J Epidemiol) Vol. 185 Issue 3 Pg. 212-223 (02 01 2017) ISSN: 1476-6256 [Electronic] United States
• PMID: 28108470 (Publication Type: Journal Article, Meta-Analysis, Review, Systematic Review)
• Copyright: © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: [email protected].

Chemical References

• Vitamin B 12

Topics

• Birth Weight
• Female
• Humans
• Infant, Low Birth Weight
• Infant, Newborn
• Pregnancy (blood)
• Pregnancy Complications
• Premature Birth (etiology)
• Risk Factors
• Vitamin B 12 (blood)
• Vitamin B 12 Deficiency (complications)