Recent evidence suggests that periconceptional folic acid use could not only prevent neural tube defects but also other malformations. The objectives of this study were to assess trends in dispensed high dose periconceptional folic acid (5 mg) and birth prevalence of major congenital malformations.
The Quebec Pregnancy Registry, an administrative database with information on periconceptional prescribed medication and diagnostic codes was used to conduct this study. All pregnant women insured by the Quebec public drug plan between January 1(st) 1998 and December 31(st) 2008 were included. The exposure was defined as the use of high dose periconceptional folic acid 30 days before, and during the first 70 days of pregnancy. The outcome measured was the birth prevalence of major congenital malformations among live births.
We identified 152,392 pregnancies and babies. The annual prevalence of high dose periconceptional folic acid use increased from 0.17% to 0.80% (p