Two previous Hungarian intervention trials showed that periconceptional folic acid-containing multivitamin supplementation did not change the total (birth + fetal) prevalence of cases with multiple congenital abnormalities (MCAs). However, two US observational studies found an elevated risk for MCAs in the offspring of women who reported periconceptional use of multivitamins containing folic acid. These conflicting results stimulated us to evaluate the data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities and to check the possible association between the use of periconceptional multivitamin supplementations and the total prevalence of cases with MCAs. Of 1,349 cases with MCA, 69 (5.1%) had mothers who used multivitamins during the second and third month of pregnancy. Of 2,405 matched controls without any defect, 126 (5.2%) had mothers who used multivitamin supplementation in early pregnancy. Of 21,494 malformed controls with isolated congenital abnormalities, 1,052 (4.9%) mothers received supplementation with multivitamins during the critical period of CAs including MCAs. There was no difference in the use of multivitamins among the study groups either in the total data set or at the evaluation of only prospective medically recorded data. Medically recorded folic acid use without any multivitamins in the second and third gestational month showed some protective effect for MCAs. In conclusion, our observational case-control study did not detect a folic acid containing multivitamins during the early pregnancy as a risk factor for MCAs.
(c) 2006 Wiley-Liss, Inc.