Mothers who smoke while pregnant may be knocking as many as four points off their baby's IQ. But intensive prenatal care may offset the loss.
The deficits turned up in a Cornell University study of three-and four-year-old children of 400 mothers who smoked at least 10 cigarettes a day when pregnant. Tots whose mothers received routine home visits from nurses during pregnancy had IQs five points higher than smokers who were not visited.
What accounts for the rebound? "The nurses were able to curb the mothers' smoking. But that's not all of it, contends Charles Henderson, research associate and coauthor of the study, reported in Pediatrics (Vol. 93, No. 2). They also improved the eating habits of the moms, 85 percent of whom were either teenagers, unmarried, or poor.
The nurses gave them all kinds of health guidelines, covering everything from nutrition, infection prevention, the appropriate use of medical care, and what to expect when the child arrives. They made hour-and-a-quarter visits about every two weeks, averaging nine visits throughout the pregnancy. They followed some of the families for two years, visiting about 23 times.