Congenital Heart Defects (CHDs) are the most common birth defects among newborns,
with 80 cases per 10,000 live births. They are a leading cause of infant mortality.
Now, results from a large study has linked first trimester maternal smoking with
some Congenital Heart Defects (CHDs). Results of this study appear in the March 2011
issue of the journalPediatrics.
In the Baltimore-Washington Infant Study, which was the first US population-based
case-control study of CHDs, case and control newborns were enrolled from 1981 to
1989. Diabetes on the parts of mothers and infants with Down’s syndrome are conditions
which are known to be associated with a higher risk of CHDs. Because of that mothers
with overt pre-pregnancy diabetes were excluded from the analysis, as were case mothers
whose infants had non-cardiac anomalies, except for atrioventricular (AV) septal
defects accompanying Down's syndrome. Therefore, the analysis included a total of
2525 case and 3435 control infants.
In-person interview after delivery allowed determination of self-reported first-trimester
maternal cigarette smoking and the rate thereof. Logistic regression models were
used to evaluate associations for 26 different groups of congenital heart defects
(CHDs) with maternal cigarette smoking. Odds ratios (ORs) were estimated for an increase
in 20 cigarettes per day.
Various types of defects caused
The types of CHDs associated with maternal smoking are truncus arteriosus, levo-transposition
of the great arteries, right ventricular outflow tract obstruction defects, pulmonary
valve stenosis, and secundum type atrial septal defect.
"Results of this study, based on a population-based design with high-quality case
ascertainment and defect classification, add to the existing body of evidence that
implicates first-trimester maternal cigarette smoking as a modest risk factor for
select congenital heart defect phenotypes," the study authors conclude.