LACTATION AND WEIGHT RETENTION

The effect of lactation on weight retention was investigated longtudin ally, with data collected at 0.5, 2, 4, 6, 12, and 18 mo after parturi tion in 110 women aged 20-40 y who had been nulliparous or primiparous . At each evaluation women were categorized as fully breast-feeding, p artly breast-feeding, or bottle-feeding including infants weaned to a bottle (bottle feeding/weaned). Postpartum weight retention was calcul ated by subtracting weight before pregnancy from weight at each evalua tion. Lactation practices were found to be significantly associated (P < 0.05) with postpartum weight retention by longitudinal regression a nalysis. Women who bottle-fed their infants retained more weight over time than women who breast-fed their infants. Significantly slower rat es of weight loss were observed when women ceased breast-feeding or sw itched from fully to partly breast-feeding. Weight retention over time was greater in women who were older, unmarried, or had greater weight gain during pregnancy (P < 0.05). A pattern of weight gain rather tha n weight loss was observed in unmarried women. Our findings suggest th at lactation influences the pattern of postpartum weight retention; ho wever, the effect of lactation on weight retention was sufficiently li mited to warrant minimal emphasis on lactation as a means of minimizin g postpartum weight retention.