AbstractObjectiveTo determine whether pre-pregnancy BMI influences breast-feeding practice.DesignRetrospective epidemiological study.SettingUniversity Hospital Leuven, Catholic University Leuven, Belgium.SubjectsTwo hundred women (median age 29 years, interquartile range (IQR) 4; 52 % nulliparae) were grouped into four categories according to pre-pregnancy BMI using WHO cut-offs.ResultsThe incidence of intention and initiation of breast-feeding was significantly lower in underweight (64 %) and obese women (68 %) compared with normal weight (92 %) and overweight women (80 %). Initiation was also related to parity (OR = 0·582; 95 % CI 0·400, 0·846), but not to gestational weight gain, method of delivery or hypertensive disorders. Fifty-two per cent of underweight, 70 % of normal weight and 56 % of overweight women were exclusively breast-feeding their infant during the first month of life. This incidence was significantly lower in the obese group (34 %; P = 0·030). Only 40 % of all infants were exclusively breast-fed at 3 months of age, with the lowest prevalence among women with obesity (P = 0·0 0 1). The median duration of any breast-feeding in the obese group (1·8 months, IQR 3·4) was significantly shorter than in the underweight (3·0 months, IQR 3·1), normal weight (3·0 months, IQR 2·4) and overweight group (3·0 months, IQR 3·5; P = 0·024). Reasons given for ceasing breast-feeding in the obese group were maternal complications (29 %), insufficient milk supply (23 %), sucking problems (21 %) and work resumption (21 %).ConclusionsBreast-feeding practice in the total population, but especially among women with obesity, fell short of global WHO recommended standards. Policy initiatives and local interventions should continue to support breast-feeding, but also prevent maternal obesity.