Downloadable study summary (requires Acrobat Reader)
25%-50% RISK REDUCTION WITH FOLIC ACID AND VITAMINS
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.
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.
Among women not taking multivitamins, those
who eat fortified cereal daily have lower risks for oral
clefts.
The risk for oral clefts is not affected
by the methylenetetrahydrofolate reductase gene (MTHFR).
GENE INTERACTION RAISES SMOKING RISK
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 mouth—the transforming growth factor-alpha
gene (TGFa). We found:
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.
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.
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.
Cutting out smoking could prevent more than
200 oral clefts in California each year.
BINGE ALCOHOL DRINKING DANGEROUS
Women who drink alcohol regularly—weekly
or even daily—do not have a higher risk of having
babies with oral clefts compared to non-drinkers.
However, "binge" drinking—5
or more drinks per occasion—weekly or more often
increases cleft lip and palate risk 3-7 times.
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.
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.
Stress. Stressful
life events—divorce, job loss or death of someone close—are
reported 30%-50% more frequently by mothers of affected infants.
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.
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.
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.
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.
DNA Repair Genes Variations among genes that repair damaged DNA during embryo development may possibly affect risk for oral clefts.
