The study, published in the Journal of Epidemiology and Community Health, used information collected from more than 13,000 children as part of the UK Millennium Cohort Study (MCS).

• The children’s mothers were categorized as
• light smokers if they smoked less than 10 cigarettes per day during their pregnancy,
• heavy smokers if they smoked more than 10 cigarettes per day,
• never having smoked during pregnancy, or
• having quit smoking during pregnancy.

To screen for behavioral problems, the mothers were asked questions about their children at age three, such as whether the child was argumentative, constantly squirmy, or easily distracted.

Think before you light up

Almost 10% of the women reported smoking heavily throughout their pregnancies, while about 13% were light smokers and another 12% quit at some point during their pregnancy.

Heavy smoking, in particular, was associated with a significantly increased risk of conduct and hyperactivity and inattention problems in boys, and conduct problems in girls.

Daughters whose mothers quit smoking during pregnancy had a lower risk of conduct problems compared with daughters of nonsmokers, suggesting to the researchers that, “the ability to quit may be an intergenerational characteristic of restraint and easy temperament.”

Beyond its role in future behavioral problems, smoking during pregnancy also increases the odds of ectopic (tubal) pregnancy, miscarriage, preterm delivery, low birth weight, and sudden infant death syndrome (SIDS). A recent study has also linked maternal smoking with psychotic symptoms such as hallucinations and delusions in adolescents. Children exposed to secondhand smoke after birth have a dramatically higher risk of developing asthma, chronic cough, and ear infections.

Better health for baby and you

Quitting smoking now greatly decreases your chance of developing smoking-related conditions such as heart disease and lung cancer later in life, and gives your baby the clean start that they deserve. For a drug-free alternative to help you quit smoking, consider acupuncture to control cravings.

(J Epidemiol Community Health 2009;doi:10.1136/jech.2009.089334)