Maternal plasma vitamin B12 concentrations during pregnancy and infant cognitive outcomes at 2 years of age

Evidence on long-term influences of maternal vitamin B-12 deficiency or concentrations on infant cognition is limited. We examined associations between maternal plasma vitamin B-12 and cognitive development in 24-month-old infants. Maternal plasma vitamin B-12 concentrations were measured at 26-28 weeks' gestation; infant cognitive development was assessed with the Bayley Scales of Infant and Toddler Development-III at 24 months, for 443 mother-infant pairs from the Growing Up in Singapore Towards Healthy Outcomes cohort. Linear regressions adjusted for key confounders examined associations of maternal vitamin B-12 with cognitive, receptive and expressive language, fine and gross motor subscales. Co-occurrence of maternal vitamin B-12 with folate or vitamin B-6 insufficiencies on child's cognition was explored. Average maternal plasma vitamin B-12 concentrations was 220 center dot 5 +/- 80 center dot 5 pmol/l; 15 % and 41 % of mothers were vitamin B-12 deficient (<148 pmol/l) and insufficient (148-220 center dot 9 pmol/l), respectively. Infants of mothers with vitamin B-12 deficiency had 0 center dot 42 (95 % CI -0 center dot 70, -0 center dot 14) sd lower cognitive scores, compared with infants of mothers with sufficient vitamin B-12. Co-occurrence of maternal vitamins B-12 and B-6 insufficiencies was associated with 0 center dot 37 (95 % CI -0 center dot 69, -0 center dot 06) sd lower cognitive scores in infants compared with infants of mothers sufficient in both vitamins. No significant associations were observed with other subscales. Study findings suggest the possible need to ensure adequate vitamin B-12 during pregnancy. The impact of co-occurrence of maternal B-vitamins insufficiencies on early cognitive development warrants further investigation.