Folic acid supplements in pregnancy and severe language delay in children

Abstract:

CONTEXT:

Prenatal folic acid supplements reduce the risk of neural tube defects and may have beneficial effects on other aspects of neurodevelopment.

OBJECTIVE:

To examine associations between mothers' use of prenatal folic acid supplements and risk of severe language delay in their children at age 3 years.

DESIGN, SETTING, AND PATIENTS:

The prospective observational Norwegian Mother and Child Cohort Study recruited pregnant women between 1999 and December 2008. Data on children born before 2008 whose mothers returned the 3-year follow-up questionnaire by June 16, 2010, were used. Maternal use of folic acid supplements within the interval from 4 weeks before to 8 weeks after conception was the exposure. Relative risks were approximated by estimating odds ratios (ORs) with 95% CIs in a logistic regression analysis.

MAIN OUTCOME MEASURE:

Children's language competency at age 3 years measured by maternal report on a 6-point ordinal language grammar scale. Children with minimal expressive language (only 1-word or unintelligible utterances) were rated as having severe language delay.

RESULTS:

Among 38,954 children, 204 (0.5%) had severe language delay. Children whose mothers took no dietary supplements in the specified exposure interval were the reference group (n = 9052 (24.0%), with severe language delay in 81 children (0.9%)).

Adjusted ORs for 3 patterns of exposure to maternal dietary supplements were

(1) other supplements, but no folic acid (n = 2480 (6.6%), with severe language delay in 22 children (0.9%); OR, 1.04; 95% CI, 0.62-1.74);

(2) folic acid only (n = 7127 (18.9%), with severe language delay in 28 children (0.4%); OR, 0.55; 95% CI, 0.35-0.86); and

(3) folic acid in combination with other supplements (n = 19,005 (50.5%), with severe language delay in 73 children (0.4%); OR, 0.55; 95% CI, 0.39-0.78).

CONCLUSION:

Among this Norwegian cohort of mothers and children, maternal use of folic acid supplements in early pregnancy was associated with a reduced risk of severe language delay in children at age 3 years.