Imbalance of folic acid and vitamin B12 is associated with birth outcome: an Indian pregnant women study

Abstract

Maternal nutrient supplementation in developing countries is generally restricted to provision of iron and folic acid. Along with folic acid, vitamin B12 is also an important determinant of fetal growth and development. During pregnancy, the increased requirement of folic acid is met with supplementation, while vitamin B12 remains untreated and possibly deficient. The objective of our study was to study the combined effect of maternal plasma folate and vitamin B12, and their ratio on birth anthropometrics. We carried out an observational study on 49 full-term pregnant women at KEM Hospital, Pune, India, during 2006-2008, and measured plasma folate, vitamin B12 and homocysteine in venous blood at 36 weeks of gestation. Neonatal anthropometrics (birth weight, length, head circumference, abdominal circumference, mid arm circumference, chest circumference, triceps skinfold and subscapular skinfold thickness) were measured within 24 h of birth. Maternal plasma folate and vitamin B12 were not correlated to neonatal anthropometrics. The combined association of folate and vitamin B12 expressed as folate to vitamin B12 ratio was correlated to the neonatal anthropometrics. Imbalance in the maternal micronutrients with increasing ratio of folate to vitamin B12 was associated with an increase in plasma homocysteine (P=0.014), lowering of neonatal birth weight (P=0.009), birth length (P=0.034), head circumference (P=0.018) and chest circumference (P=0.009), while no significant association to other anthropometrics was observed. Supplementation of vitamin B12 in addition to supplementation of folic acid in pregnancy may be important for improving birth weight, birth length, head circumference and chest circumference.