Journal Article

Spontaneous preterm birth and small for gestational age infants in women who stop smoking early in pregnancy: prospective cohort study

Hunter, Misty, Dekker, Gustaaf A, Moss-Morris, Rona, Stewart, Alistair, McCowan, Lesley M E, North, Robyn A, Chappell, Lucy C, Chan, Eliza

2009

Overview

Objectives To compare pregnancy outcomes between women who stopped smoking in early pregnancy and those who either did not smoke in pregnancy or continued to smoke.Design Prospective cohort study.Setting Auckland, New Zealand and Adelaide, Australia.Participants 2504 nulliparous women participating in the Screening for Pregnancy Endpoints (SCOPE) study grouped by maternal smoking status at 15 (±1) week’s gestation.Main outcome measures Spontaneous preterm birth and small for gestational age infants (birth weight <10th customised centile). We compared odds of these outcomes between stopped smokers and non-smokers, and between current smokers and stopped smokers, using logistic regression, adjusting for demographic and clinical risk factors.Results 80% (n=1992) of women were non-smokers, 10% (n=261) had stopped smoking, and 10% (n=251) were current smokers. We noted no differences in rates of spontaneous preterm birth (4%, n=88 v 4%, n=10; adjusted odds ratio 1.03, 95% confidence interval l0.49 to 2.18; P=0.66) or small for gestational age infants (10%, n=195 v 10%, n=27; 1.06, 0.67 to 1.68; P=0.8) between non-smokers and stopped smokers. Current smokers had higher rates of spontaneous preterm birth (10%, n=25 v 4%, n=10; 3.21, 1.42 to 7.23; P=0.006) and small for gestational age infants (17%, n=42 v 10%, n=27; 1.76, 1.03 to 3.02; P=0.03) than stopped smokers.Conclusion In women who stopped smoking before 15 weeks’ gestation, rates of spontaneous preterm birth and small for gestational age infants did not differ from those in non-smokers, indicating that these severe adverse effects of smoking may be reversible if smoking is stopped early in pregnancy.

• Publisher: British Medical Journal Publishing Group,British Medical Association,BMJ Publishing Group LTD,BMJ Publishing Group Ltd
• Subject: Adult / Anxiety / Babies / Birth weight / Blood pressure / Child Health / Cohort analysis / Cohort studies / Creatinine / Epidemiologic Studies / Female / Gestational age / Health care / Health Education / Health Promotion / Humans / Infant, Newborn / Infant, Small for Gestational Age / Infants / Menstruation / Midwifery / Minority & ethnic groups / Miscarriage / Preeclampsia / Pregnancy / Pregnancy complications / Pregnancy Outcome / Pregnancy Trimester, First / Premature birth / Premature Birth - etiology / Prospective Studies / Proteins / Questionnaires / Regression analysis / Reproductive Medicine / Screening (Epidemiology) / Screening (Public Health) / Small for gestational age / Smoking / Smoking - adverse effects / Smoking and Tobacco / Smoking Cessation / Womens health