Smoking during pregnancy increases the risk of the mother having complications during pregnancy and the baby being born too small (with low birthweight) and too early (prematurely, before 37 weeks). Low birthweight has been associated with coronary heart disease, type 2 diabetes, and being overweight in adulthood. Tobacco smoking also has serious long-term health risks for both the women and their babies. Tobacco smoking during pregnancy is relatively common, although the trend is toward becoming less frequent in high-income countries and more so in low to middle-income countries. Many mothers find it hard to stop or reduce smoking during pregnancy even knowing the benefits of doing so as the nicotine in tobacco is very addictive. Smoking in pregnancy is also strongly associated with poverty, low levels of education, poor social support, depression and psychological illness.
The interventions offered to promote smoking cessation in pregnancy are generally given individually and include cognitive behaviour and motivational interviewing; offering incentives; interventions based on stages of change; giving feedback to the mothers on fetal health status or nicotine by-products measurements; nicotine replacement therapy, bupropion or other medications. The review of trials found a total of 72 controlled trials involving over 25,000 women. These were conducted from 1975 to 2008 and nearly all were in high-income countries. Interventions were effective in helping women to stop smoking during pregnancy (overall by approximately 6%). The most effective intervention appeared to be providing incentives, which helped around 24% of women to quit smoking during pregnancy. The smoking cessation interventions reduced the number of babies with low birthweight and preterm births, confirming that smoking cessation can reduce the adverse effects of smoking on newborn infants.
Women in the control groups of most trials received information about the risks of smoking in pregnancy and were advised to quit as part of usual care. The intensity of both that information and the interventions has increased over time.