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clefts: study findings


The California Birth Defects Monitoring Program was the first to report a protective effect from multivitamins with folic acid and oral clefts. Our continued search to understand this effect investigates the role of genes that may alter folic acid metabolism.

bullet Mothers taking multivitamins containing folic acid are less likely to have babies with oral clefts. Risk reductions range from 25%-50%, depending on the type of cleft. reference information PDF file
bullet Among women not taking multivitamins, those who eat fortified cereal daily have lower risks for oral clefts.
bullet The risk for oral clefts is not affected by the methylenetetrahydrofolate reductase gene (MTHFR). reference information


About 1 in 4 California women smoke during pregnancy. But some infants may be genetically more susceptible to mothers' smoking. The Program looked at mothers' smoking habits in combination with a gene normally involved in development of the palate and mouththe transforming growth factor-alpha gene (TGFa). We found:

bullet Women who smoke during pregnancy are 1.5-2 times as likely to have babies with oral clefts. The more cigarettes the mother smokes, the higher the risk.
bullet The hazards of smoking are even greater for the 1 in 7 babies with a cleft-susceptiblity gene (the A2 form of TGFa). They are 8 times as likely to have oral clefts if their mothers smoke. Those born to nonsmoking mothers are at no greater risk.
bullet Nonsmoking mothers exposed to secondhand smoke have only a small, if any, increased risk. The father's smoking increases the risk for oral clefts only if the mother smokes too.
bullet Cutting out smoking could prevent more than 200 oral clefts in California each year. reference information PDF file


bullet Women who drink alcohol regularlyweekly or even dailydo not have a higher risk of having babies with oral clefts compared to non-drinkers.
bullet However, "binge" drinking5 or more drinks per occasionweekly or more often increases cleft lip and palate risk 3-7 times. reference information

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bullet Corticosteroids. Drugs such as cortisone and prednisone (used to treat asthma, autoimmune diseases and inflammation) are linked with a 4-5 times increase in risk for cleft lip and/or cleft palate. reference information
bullet Hazardous waste sites. Women who lived within 1/4 mile of a Superfund hazardous waste site during the first 3 months of pregnancy are no more likely to have a chid with oral clefts. reference information
bullet Stress. Stressful life eventsdivorce, job loss or death of someone closeare reported 30%-50% more frequently by mothers of affected infants. reference information
bullet Vitamin A. High doses of vitamin A induce birth defects in laboratory animals; however, we found no higher risk for oral clefts among mothers who take vitamin A supplements during pregnancy. reference information

More on Smoking Infants who have a variant of NAT1, an enzyme that normally helps process chemicals from cigarette smoke, are more likely to have an oral cleft if their mothers smoked during pregnancy. reference information

Women who smoke increase the risk for clefts among babies who have a gene variation of Glutathion S-Transferases, another enzyme that helps process chemicals from cigarette smoke. reference information
bullet Multivitamin Use Mothers who did not use multivitamins during early pregnancy had a higher risk to deliver a baby with cleft lip when their babies had a specific variant of the NAT1 gene. reference information

DNA Repair Genes Variations among genes that repair damaged DNA during embryo development may possibly affect risk for oral clefts. reference information

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