Smoking in pregnancy 'affects boys' fitness in later life'

For the first time, a small Finnish study has examined the impact of maternal smoking on the long-term health of male offspring. Of the 508 young men (average age 19) included in the study 59 of their mothers smoked more than one cigarette a day throughout pregnancy. Results found that maternal smoking was associated with lower aerobic fitness of their children, which was measured by ability on a running test at the beginning of their military service assessment. Aerobic activity was also independently associated with their own smoking status, weight and physical activity.

The study also found that higher maternal pre-pregnancy BMI and excessive weight gain during pregnancy were associated with lower aerobic fitness in the offspring.

Dr Maria Hagnäs from the University of Oulu, Finland, and lead author of the study said: "It's well established that smoking and breathing in second-hand smoke are harmful for both mother and baby. Our study adds to the existing evidence base of the negative and long-standing impacts of maternal smoking. Women must receive advice and support to help them stop smoking during pregnancy, as well guidance on how to maintain a healthy weight to minimise the risks to their unborn child."

The health risks associated with smoking, and the benefits of stopping smoking, are well known. Mothers who smoke are at a higher risk of miscarriage, ectopic pregnancy, intrauterine growth restriction, premature birth and stillbirth. Their babies are also more likely to suffer from birth defects, and neurological, psychological or behavioural difficulties. In addition, babies born to mothers who smoke have a greater risk of asthma, chest and ear infections and pneumonia as well as being more susceptible to infant death syndrome. Although more likely to be small babies, they are at increased risk of obesity and insulin resistance (the precursor of diabetes) later in life.

Dr Geeta Kumar, Chair of the RCOG's Patient Information Committee, said: "Stopping smoking is one of the most important things a pregnant woman can do to improve their baby's health, growth and development, and this study demonstrates the negative effect smoking in pregnancy can have on a child's long-term health too.

"It is important that women understand the risks of smoking in pregnancy and are aware of the support that is available to help them stop. Women who are unable to quit smoking should be encouraged to abstain during their pregnancy, use nicotine replacement therapy, or to reduce smoking as much as they can. We encourage all healthcare professionals working with pregnant women to access the RCOG's new patient information leaflet which contains practical and evidence-based advice and guidance to share with women about smoking during pregnancy."