Smoking in pregnancy tied to kids’ conduct problems
Children of women who smoked cigarettes during pregnancy are more likely to have behavioral problems than those whose mothers didn’t light up, says a new analysis.
“The evidence is emerging that smoking in pregnancy and the frequency of smoking in pregnancy is correlated with developmental outcomes after (children) are born,” said Gordon Harold, the study’s senior author from the University of Leicester in the UK.
Previous research has tied smoking cigarettes during pregnancy to behavior problems among children later on, but those studies couldn’t rule out the influence of other factors, such as genetics or parenting techniques, researchers said.
For example, Harold and his colleagues write in JAMA Psychiatry that mothers who smoke during pregnancy are more likely to have parenting styles that condone acting out.
For the new analysis, the researchers pulled together data from three studies from New Zealand, the UK and the U.S. that asked women whether or not they smoked cigarettes during pregnancy. Parents and teachers then reported on children’s conduct problems - such as getting in fights or having difficulty paying attention - between age four and 10.
The analysis also compared children who were raised by adoptive mothers to children who were raised by their biological mothers in an effort to tease out the influence of genetics and parenting styles on any link between prenatal smoking and behavior.
The researchers compared children’s behavior scores to an average of 100, where higher scores indicate more conduct problems.
In studies that looked at women who raised their own biological children, those who didn’t smoke during pregnancy had kids who scored about a 99, on average, compared to a score of 104 among children whose mothers smoked 10 or more cigarettes per day.
How Many Women Smoke During Pregnancy?
According to the 2008 Pregnancy Risk Assessment and Monitoring System (PRAMS) data from 29 states-
Approximately 13% of women reported smoking during the last three months of pregnancy.
Of women who smoked 3 months before pregnancy, 45% quit during pregnancy. Among women who quit smoking during pregnancy, 50% relapsed within 6 months after delivery.
For more statistics on smoking during pregnancy see: PRegnancy Risk Assessment Monitoring System (PRAMS) and SMoking, Data from 2000–2008.
That difference, according to Harold, would be noticeable in daily life.
Similar results were observed for children who were raised by adoptive mothers when researchers surveyed their birth mothers about smoking.
Smoking and the unborn baby
Protecting your baby from tobacco smoke is one of the best things you can do to give your child a healthy start in life. It’s never too late to stop smoking. Every cigarette you smoke conains over 4,000 chemicals, so smoking when you are pregnant harms your unborn baby. Cigarettes can restrict the essential oxygen supply to your baby, so their heart has to beat harder every time you smoke.
If you stop smoking now
Stopping smoking will benefit both you and your baby immediately. Harmful gases like carbon monoxide and other damaging chemicals will clear from your body. When you stop smoking:
you will have less morning sickness and fewer complications in pregnancy
you are more likely to have a healthier pregnancy and a healthier baby
you will reduce the risk of stillbirth
you will cope better with the birth
your baby is less likely to be born too early and have to face the additional breathing, feeding and health problems that often go with being premature
your baby is less likely to be born underweight: babies of women who smoke are, on average, 200g (about 8oz) lighter than other babies, which can cause problems during and after labour, for example they are more likely to have a problem keeping warm and are more prone to infection
you will reduce the risk of cot death, also called sudden infant death (find out about reducing the risk of cot death)
Stopping smoking will also benefit your baby later in life. Children whose parents smoke are more likely to suffer from asthma and other more serious illnesses that may need hospital treatment.
The sooner you stop smoking, the better. Even if you stop in the last few weeks of your pregnancy this will benefit you and your baby.
While the new study cannot prove smoking in pregnancy caused the behavior problems, Harold told Reuters Health it helps rule out some other potential explanations.
“It’s illuminating the prenatal period as having an ongoing influence on outcomes,” Harold said.
“We’re not saying life after birth is no longer relevant… Rather, both influences are clearly important,” he said.
Harold said there are a few explanations for why smoking may influence later conduct, including that babies of mothers who smoke may be born smaller or have impaired brain development.
In an accompanying editorial, Theodore Slotkin, a professor of pharmacology and cancer biology at the Duke University School of Medicine in Durham, North Carolina, writes that it’s undeniable that smoking while pregnant contributes to later behavior problems in children, based on the new study and past research.
He also told Reuters Health the concern goes beyond women’s own smoking.
“It’s one thing if mom is smoking, but what if mom is getting exposed from a partner or a smoking environment?” Slotkin said.
How Does Smoking During Pregnancy Harm My Health and My Baby?
Most people know that smoking causes cancer, heart disease, and other major health problems. Smoking during pregnancy causes additional health problems, including premature birth (being born too early), certain birth defects, and infant death.
Smoking makes it harder for a woman to get pregnant.
Women who smoke during pregnancy are more likely than other women to have a miscarriage.
Smoking can cause problems with the placenta - the source of the baby’s food and oxygen during pregnancy. For example, the placenta can separate from the womb too early, causing bleeding, which is dangerous to the mother and baby.
Pregnant coupleSmoking during pregnancy can cause a baby to be born too early or to have low birth weight - making it more likely the baby will be sick and have to stay in the hospital longer. A few babies may even die.
Smoking during and after pregnancy is a risk factor of Sudden Infant Death Syndrome (SIDS). SIDS is an infant death for which a cause of the death cannot be found.
Babies born to women who smoke are more likely to have certain birth defects, like a cleft lip or cleft palate.
Harold said the new findings add to the reasons for women not to smoke while pregnant.
“Providing a healthy and safe prenatal environment, giving that child the best possible starting place, helps the child in the long term,” he said.
SOURCE: JAMA Psychiatry, online July 24, 2013
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Although there is widespread consensus that maternal smoking during pregnancy has adverse, long-term effects on neurobehavioral development in the offspring, it has been surprisingly difficult to prove that there are specific behavioral problems that can be incontrovertibly attributed to prenatal tobacco smoke exposure. It is now 16 years since a relationship was first postulated between maternal smoking and conduct disorder in the offspring, and in the intervening years, there have been numerous studies in support of a causal relationship, as well as studies claiming that other confounds obscure any role of tobacco. The article by Gaysina et al2 resolves this issue once and for all by examining the connection in 3 distinct, longitudinally followed up cohorts, incorporating not only the standard battery of covariables in such studies, but also involving genetically related and unrelated families with children raised by biological or adoptive parents. Therefore, their meta-analysis controls for perinatal and postnatal confounds including differences in child-rearing practices or the home environment. Thus, the conclusion is incontrovertible: prenatal tobacco smoke exposure contributes significantly to subsequent conduct disorder in the offspring. Considering the relationship of conduct problems to poor school performance, social isolation, and juvenile and adult incarceration, the negative impact on the affected individuals’ quality of life and, ultimately, on society as whole, cannot be underestimated.
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JAMA Psychiatry. 2013;():-. doi:10.1001/jamapsychiatry.2013.1951
Theodore A. Slotkin, PhD