Breast-feeding mothers can exercise: results of a cohort study.

OBJECTIVES To study the relationship between exercise by the mother and breast-feeding initiation and duration, and its effect on infant growth. DESIGN A cohort study of mothers and infants, recruited at birth. Infant feeding methods were recorded in detail and breast-feeding was categorised as 'any' or 'full'. Exercise levels were categorised using the metabolic equivalent tasks approach based on details of physical activity recorded in questionnaires. SETTING Perth, Western Australia. SUBJECTS A total of 587 mothers were interviewed on seven occasions over a period of 12 months. RESULTS There was no difference in the means of infant weight and length changes, indicating that exercise appeared to have no significant influence on infant growth up to 52 weeks after birth (P=0.236 and 0.974, respectively). The mother's level of exercise was not significantly associated with breast-feeding to 6 or 12 months. This applied to 'full' and 'any' categories of breast-feeding. CONCLUSION Exercise does not affect breast-feeding outcomes at the usual levels of activity undertaken by mothers. Breast-feeding and exercise are important for maintaining and promoting health, and this study provides reassurance to health professionals wishing to encourage mothers to continue both behaviours.