Determinants of cobalamin status in newborns

Objective. Cobalamin deficiency accompanied by bone marrow dysfunction and impaired central nervous system development has been reported in infants wh o were born to mothers with low cobalamin intake. We investigated the relat ion between cobalamin status in newborns and in their healthy mothers who c onsumed an omnivorous diet. Methods. Serum cobalamin and the functional markers plasma methylmalonic ac id (MMA) and total homocysteine (tHcy) were determined in 173 newborns and their mothers. Forty-five children and mothers were reinvestigated after 6 weeks. Results. At birth, median (interquartile range) serum cobalamin levels were 245 (175-323) pmol/L in the mothers and 314 (238-468) pmol/L in the newbor ns. In the neonates, serum cobalamin, but not folate, was inversely associa ted with MMA and tHcy. Among maternal factors, low serum cobalamin was the strongest predictor of impaired cobalamin function (defined as low cobalami n, high tHcy, or high MMA levels) in the newborns. After 6 weeks, the mater nal cobalamin levels had increased (to 421 [271-502] pmol/L), whereas the n ewborn levels had declined (to 230 [158-287] pmol/L). In the same interval, the infants had a marked increase in plasma MMA (from 0.29 [0.24-0.38] to 0.81 [0.37-1.68] mmol/L). At 6 weeks, parity was a strong predictor of coba lamin status in the infant. Conclusion. The cobalamin status in the neonatal period is strongly associa ted with maternal cobalamin status and parity. A reduction in serum cobalam in and an increase in metabolite levels are consistent with impaired cobala min function in a significant portion of the infants who were born to healt hy, nonvegetarian mothers.