Q: Do I have only 800 words to write about the ill-effects of maternal smoking?
A: Yes. So I’ll get to work fast. Smoking is toxic at any age or in any sex, of course; since the 1964 Surgeon General’s Report on Smoking and Health, not even makers of tobacco products can claim their products are safe. Every year since, the mountain of evidence against the evil weed has grown. And if that is Mount Everest, the evidence of ill effects of smoking by parents, especially mothers, is like a Hawaiian volcano: always growing as new evidence rolls glowing down its sides.
Wanting to limit my search, I went only to my favorite pediatric journal, called Pediatrics, and found 174 articles on effects of maternal smoking since 1964. Listing just titles would take up all my 800 words, so I’ll summarize. Don’t do it. This is not a gender-neutral issue: mothers smoking during pregnancy cause many more ill-effects than fathers smoking during those nine months. That shouldn’t surprise anyone, because anything taken into a mother’s bloodstream is shared with her baby while the father’s circulation remains apart.
One of the most important problems with mothers smoking, known for many years, is tobacco causing a considerable decrease in the size of infants. Bigger isn’t always better, as the ads say, but being of adequate size at birth is associated with much better outcome than being small for the period spent in the uterus.
More subtle effects have also been proven by careful research comparing the 12.2 percent (year 2000 figure, compared to 19.5 percent in 1989) of babies born to smoking mothers with the remaining 87.8 percent. Maybe most important are the comparisons of behavior and intelligence. All of us would give a great deal to have our children be even more intelligent than they are – the incidence of mental retardation in the mother-smoked group is about 50 percent higher than in the group whose mothers did not.
A great many mothers in my practice over the years would have done anything – anything! – to avoid the colic that caused them many sleepless nights. Colic is much more common among the mother-smoked group, perhaps because smoking tobacco stimulates production of an intestinal hormone called motilin. But motilin is unlikely to be the factor that causes children of smoking mothers to have a higher likelihood of behavior problems during infancy and toddlerhood than infants whose mothers did not smoke during pregnancy. One researcher, using a large data set, calculated that the frequency of extreme behavior problems in childhood was 41 percent higher with mothers who smoked less than a pack of cigarettes a day and 54 percent higher if she smoked more than one pack.
We don’t really know what causes colic, and we also have no certainty about what causes attention deficit disorder (ADHD), a serious and common problem affecting about 8 percent to 10 percent of American schoolchildren. (That’s the condition that many of us remember in children we encountered during our own childhood, who disrupted their classes with their bull in the china shop activity, their impulsivity and their inability to keep their attention on anything.) We do know, however, that smoking mothers have a two to three times increased risk of having a child with ADHD.
Sudden infant death in infants is still the most common cause of death in infants beyond their first month. Although we still don’t know its cause, evidence points clearly to two major risk factors – sleeping face down and maternal smoking. Mothers who smoke are two to four times as likely to have a baby die suddenly and unexpectedly as women who do not smoke, according to a number of studies.
It probably won’t surprise you that maternal smoking is associated with asthma in children, whether the mother smokes just during pregnancy, just after the baby is born or both. After all, everyone, even smokers, know that smoking affects the lungs of smokers, so why not of children? Most of us are aware, too, that smokers are subject to a higher risk of heart attack than nonsmokers, so it may not come as a surprise that many malformations of the heart in infants are also related to maternal smoking – 30 percent to 50 percent more likely. Smoking even affects the developing hips of newborns – mothers who smoked were much more likely to have infants with a serious hip problem called Legg-Perthes disease – about twice the rate of nonsmokers.
I’m out of space, not out of associations between maternal smoking and disease. It’s often been said that if there had been an FDA when Sir Walter Raleigh first popularized tobacco use in the 1500s, the drug (for that’s what it is) would never have been approved. It certainly would have been labeled Pregnancy Category X. Children should not be exposed to X-rated movies or X-rated drugs like tobacco.
Lance Chilton, M.D., is a pediatrician at the Young Children’s Health Center in Albuquerque, associated with the University of New Mexico. He is happy to take questions at 272-9242 or firstname.lastname@example.org.