Population-based case control study of folic acid supplementation during pregnancy.
Previous studies have demonstrated that periconceptional folic acid/multivitamin supplementation reduced the occurrence of neural tube defects. A case control analysis has been conducted in the dataset of the Hungarian Case Control Surveillance of Congenital Abnormalities, 1980-1991. In the study period, 54.9% of 30,663 pregnant women who had healthy babies (negative control group) were supplemented with high doses (in general 2 x 3 mg) of folic acid per day. In those 17,300 pregnant women who had offspring with congenital abnormalities, the rate of folic acid supplementation was 50.4%. Exposure histories: preconceptional, I, II, III, and IV-IX postconceptional months were determined by record reviews and questionnaire assessment. The case control pair analysis showed a significant protection after folic acid supplementation during the critical period of cardiovascular defects, neural tube defects, cleft lip with or without cleft palate and posterior cleft palate.
Department of Human Genetics and Teratology, National Institute of Hygiene, WHO Collaborating Centre for the Community Control of Hereditary Diseases, Budapest, Hungary.
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Czeizel
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Tóth
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Rockenbauer
D016022:Case-Control Studies; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D009436:Neural Tube Defects / Q000139:chemically induced; D011247:Pregnancy
D005492:Folic Acid