The relationship between maternal smoking and breastfeeding duration after adjustment for maternal infant feeding intention.

AIM To investigate whether maternal smoking remains associated with decreased breastfeeding duration after adjustment for the mother's infant feeding intention. METHOD Pregnant women resident within Avon, UK, expected to give birth between 1 April 1991 and 31 December 1992 were recruited in a longitudinal cohort study. Main outcome measures included maternal infant feeding intention at 32 wk of pregnancy: intention for the first week, intention for the rest of the first month and intention in months 2 to 4. Maternal smoking was defined as any smoking reported at any time during pregnancy. Data on initiation and duration of breastfeeding were based on the questionnaire at 6 mo postpartum, supplemented by data from the 15-mo questionnaire if necessary. RESULTS Women who smoked during pregnancy had an adjusted odds ratio of 1.5 (95% CI: 1.3-1.7) of not breastfeeding at 6 mo compared to non-smokers (adjusting for maternal age, education and intention). Survival analysis of duration of breastfeeding in the first 6 mo postpartum found that women who intended to breastfeed for less than 1 mo were 78% more likely to stop at any given time than women planning to breastfeed for at least 4 mo, while smokers were 17% more likely to stop breastfeeding than non-smokers. CONCLUSION Although women who smoke are less likely to breastfeed their infants than are non-smoking women, it appears that this is largely due to lower motivation to breastfeed rather than a physiological effect of smoking on their milk supply.