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
Rogne, Tormod; Tielemans, MJ; Chong, MF; Yajnik, CS; Krishnaveni, GV; Poston, Lucilla; Jaddoe, VW; Steegers, EA; Joshi, S; Chong, YS; Godfrey, KM*; Yap, F; Yahyaoui, R; Thomas, T; Hay, Gry; Hogeveen, M; Demir, Ahmet; Saravanan, P; Skovlund, Eva; Martinussen, Marit; Jacobsen, Geir Wenberg; Franco, OH; Bracken, Michael B; Risnes, Kari
Journal article, Peer reviewed
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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.
available from 2018-02-01