Maternal smoking during and after pregnancy and lung function in early adulthood: A prospective study

Mohammad Reza Hayatbakhsh ^1*, Suresh Sadasivam ², Abdullah A Mamun ¹, Jake M Najman ¹ and Michael J O'Callaghan ²

¹ University of Queensland, Australia
² Mater Children's Hospital, Australia

^* To whom correspondence should be addressed. E-mail: m.hayatbakhsh{at}uq.edu.au.

Accepted 1 June 2009

Abstract

Background and aim: There is a paucity of evidence about whether exposure to antenatal smoking impacts on offspring’s lung function in early adulthood. This study aimed to examine whether 1) in utero exposure to maternal smoking is related to poorer respiratory functioning in early adulthood; 2) the impact of prenatal smoking is independent of postnatal maternal smoking; and 3) the link between prenatal smoking and young adult’s lung function is explained by the child’s birthweight, smoking or history of asthma.

Methods: Data were from a 21-year follow-up of mothers and their children recruited into the Mater-University of Queensland Study of Pregnancy, a longitudinal pre-birth cohort. The study is based on 2409 young adults (1185 males and 1224 females) who had prospective data available on respiratory function at 21 years and maternal smoking during and after pregnancy. A Spirobank G spirometer system was used to measure forced vital capacity (FVC), forced expiratory volume in first second (FEV₁)and forced expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75).

Results: In utero exposure to maternal smoking was associated with a reduction in FEV₁ and FEF_25-75 in males (regression coefficient = -0.16, 95% confidence interval: -0.30, -0.02), after accounting for maternal smoking after pregnancy. At least part of the effect of in utero smoking on young adult’s lung function was explained by child birth weight and subsequent asthma.

Conclusions: Adverse affect of antenatal smoking on development of airway growth may persist into early adulthood. Gender differences noted in this longitudinal cohort needs to be further explored.