(HealthDay News) – Breastfeeding correlates with a small but significant reduction in body mass index (BMI) much later in life.

Kirsty L. Bobrow, from the University of Oxford in the United Kingdom, and colleagues explored the long-term effects of women’s childbearing patterns on their BMI in a population-based study of 740,628 postmenopausal women (average age, 57.5 years; mean BMI, 26.2kg/m²).

The researchers found that 88% of the women were parous with an average of 2.1 children. There was a progressive increase in the standardized BMI with an increasing number of births, from 25.6kg/m² for nulliparous women to 27.2kg/m² for women with four or more births. Seventy percent of parous women had breastfed, with an average total duration of 7.7 months. The standardized mean BMI was significantly lower for women who had breastfed compared with those who had not breastfed at every parity level, with a decrease of 0.22kg/m² for every six months of breastfeeding. These correlations were statistically significant and were not affected by socioeconomic group, region of residence, physical activity, and smoking.

“During peripartum counseling on infant feeding choices, it seems relevant to inform women that breastfeeding is associated with a relatively small, but important, persistent reduction in their weight decades later,” the authors write.

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