Abstract 4550: Periconceptional Folic Acid Supplementation and the Preventive Effect on the Risk of Congenital Heart Defects: A Registry Based Case-Control Study in the Northern Netherlands
Evidence is emerging that periconceptional folic acid supplements protect against congenital heart defects (CHD). We aimed to explore the potentially protective effect of periconceptional folic acid use on CHD risk. We analysed data from a large regional register of birth defects (EUROCAT- Northern Netherlands), over a ten-year period (1996 –2005) for a case-control study. The cases consisted of mothers who had delivered infants with isolated or complex heart defects, without any related syndrome or genetic abnormality (n=611). The control group consisted of mothers of children with a known chromosomal or genetic defect, and with infants with other congenital malformations (n=2401). Mothers who had used folate antagonists or who had diabetes, and mothers of children with oral cleft, hypospadia, limb reduction- or neural tube defects, were excluded from both groups. Potentially confounding factors of periconceptional folic acid use in relation to CHD were explored, including baby’s birth year, maternal body mass index, education, maternal age at delivery of index baby, smoking behaviour and alcohol use during pregnancy. The estimated relative risks for different types of CHD associated with maternal periconceptional folic acid supplements are presented in the table⇓. Adequate use of periconceptional folic acid supplements revealed an odds ratio of 0.82 (95% CI 0.68 – 0.98) for all types of CHD. Subgroup analysis showed an odds ratio of 0.62 (95% CI 0.47– 0.82) for isolated septal defects. The proportions of the potential confounders between mothers of case and control infants did not differ significantly. Our results support the hypothesis that adequate folic acid supplements reduce CHD risk in infants. Use of periconceptional folic acid supplements was related to approximately 20% reduction in the prevalence of any CHD. Given the relatively high prevalence of CHD worldwide, our findings are important for public health.