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.
Czeizel
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Department of Human Genetics and Teratology, National Institute of Hygiene, WHO Collaborating Centre for the Community Control of Hereditary Diseases, Budapest, Hungary.
Tóth
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M
Rockenbauer
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M
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