Smoking during pregnancy and child mental health and wellbeing: evidence, policy and practice

Aim: The aim of this thesis was to further understand the link between maternal smoking during pregnancy and mental health outcomes among children. The thesis comprises (a) a longitudinal epidemiological analysis of smoking during pregnancy and child mental health outcomes using cohort data for UK children from before birth to 7 years of age (b) an exploration of what policy documents, official guidance and qualitative studies tell us about how the epidemiological risks of smoking in pregnancy are reflected in public policy and discourse. Methods: Existing epidemiological evidence was reviewed prior to the quantitative analyses. The data analysed are from the Millennium Cohort Study. Data for 13,161 mothers and children, analysed longitudinally, were used to link exposure to maternal smoking during pregnancy to child mental health outcomes (hyperactivity and aggressive behaviour) at 3, 5 and 7 years of age. Additionally a review of official and lay health guidance in two countries (United Kingdom and United States) was conducted to ascertain the extent to which the potential link between maternal smoking during pregnancy and increased risk of child mental health problems is reflected in ante-natal care policy and practice in these countries. Similarly, a review of qualitative studies was conducted to ascertain the extent to which the risk of child mental health problems is reflected in women's perceptions of the risks of smoking during pregnancy. Results: During the past 10 years high-quality studies (and studies of lower quality) have consistently observed an association between prenatal smoking exposure and child mental health problems, though a few well designed recent studies have provided conflicting findings, and further disentangling of exposure and potential confounding factors is needed. Prenatal smoking, socioeconomic position, genetics, family environment, parental mental health and other chemical and environmental exposures, including other endocrine disrupting chemicals, should be explored together, and in more depth, to understand the associations that have been observed between maternal smoking during pregnancy and child mental health during the past 20 years. The original and significant contribution of this thesis is a confirmation of the link between smoking in pregnancy and the development of disruptive behaviour problems in children in a large population-based sample from the United Kingdom. In terms of policy and discourse, ante-natal care packets could be modified to include information about these risks for pregnant women. Conclusions: Child mental health, prenatal smoking and the economic well- being of families are interlinked–so policies aimed at helping pregnant women to quit smoking, as well as those to help them out of disadvantage are likely to have positive effects on both the exposure (prenatal smoking) and the outcome (child mental health)