Protective effect of periconceptional folic acid supplements on the risk of congenital heart defects: a registry-based case-control study in the northern Netherlands

To investigate the potentially protective of periconceptional folic acid use on the risk of congenital heart defects (CHDs) relative to other non-folate related malformations. We analysed data from a large regional register of birth defects (EUROCAT—Northern Netherlands), over a 10 year period (1996–2005) for a case–control study. The cases were mothers who had delivered infants with isolated or complex heart defects, without any related...