Multivitamin Supplementation and Risk of Brith Defects

Abstract

It is widely accepted that supplementation with folic acid, a B vitamin, reduces the risk of neural tube defects (NTDs). This case-control study tested the hypothesis that multivitamins reduce risks of selected birth defects other than NTDs. Infants with and without birth defects and aborted fetuses with birth defects were ascertained in the greater metropolitan areas of Boston, Philadelphia, and Toronto during 1993-1996. Mothers were interviewed within 6 months after delivery about a variety of factors, including details on vitamin use. Eight case groups were included: cleft lip with or without cleft palate, cleft palate only, conotruncal defects, ventricular septal defects, urinary tract defects, limb reduction defects, congenital hydrocephaly, and pyloric stenosis (n's ranged from 31 to 186). Controls were 521 infants without birth defects (nonmalformed controls) and 442 infants with defects other than those of the cases (malformed controls). Daily multivitamin supplementation was evaluated according to gestational timing categories, including periconceptional use (28 days before through 28 days after the last menstrual period). Odds ratios (ORs) below 1.0 were observed for all case groups except cardiac defects, regardless of control type. For periconceptional use, ORs with 95% confidence intervals that excluded 1.0 were estimated for limb reduction defects using both nonmalformed controls (OR = 0.3) and malformed controls (OR = 0.2) and for urinary tract defects using both nonmalformed controls (OR = 0.6) and malformed controls (OR = 0.5). Statistically significant ORs for use that began after the periconceptional period were observed for cleft palate only and urinary tract defects. These data support the hypothesis that periconceptional vitamin supplementation may extend benefits beyond a reduction in NTD risk. However, other than folic acid's protecting against NTDs, it is not clear what nutrient or combination of nutrients might affect risk of other specific defects.

Uso de medicamentos por gestantes em seis cidades brasileiras

“…Apesar de o uso de ácido fólico durante a gestação ter seus benefícios estabelecidos, apenas 16% das gestantes utilizaram esse medicamento, na maioria dos casos por meio de preparações multivitamínicas para as quais a literatura não mostra evidências fortes de benefício. 5,19 No presente estudo, aproximadamente 1/4 das gestantes utilizou analgésicos, sendo a dipirona o mais freqüente (43%), seguido do ácido acetilsalicílico (33%) e do paracetamol (18%). Na literatura, o uso de analgésicos apresentou freqüências que variaram de 18% até 76%.…”

Chemical exposure during pregnancy and oral clefts in newborns

“…Given the possibility that fetal deficiency in both the transport and metabolism of folic acid places the fetus at increased risk for this malformation, and that maternal folic acid supplementation is not effective in all individuals, it is important to identify potential candidate genes for regulating this process (Finnell et al, 1998). Werler et al (1999) highlight that it is not clear which combination of nutrients or which specific nutrient is related to risk reduction for other malformations, since many vitamin supplements include 7 out of 8 water-soluble vitamins and 3 fat-soluble vitamins, in addition to at least 4 minerals or trace elements.…”

Correlates of intake of folic acid–containing supplements among pregnant women

“…4,[11][12][13][14] Intake during early pregnancy is critical because most birth defects occur during the first few weeks of pregnancy. For example, neural tube closure is completed by day 28 after conception, or 6 weeks after the last menstrual period.…”