The association of pregnancy weight gain with the mother's postpartum weight.

The association between pregnancy weight gain and the mother's weight at intervals following delivery was studied using the records of two clinics serving low-income populations. All the prenatal patients on whom complete data were available for a 2-year period were used. The 158 pregnant women gained a mean of 12.9 kg during their pregnancies; 44% gained more than 13.6 kg and 25% gained less than 9.1 kg. Three months after delivery the women showed gains significantly greater than those experienced by a nonpregnant comparison group during a comparable period. Maternal weight gain was determined by subtracting the infant's birth weight from the mother's total gain during pregnancy. Weight changes at three periods postpartum were compared among maternal weight gain tertiles. Sustained weight gains resulted in 39% of the women in the upper tertile being newly classified as overfat 1 to 3 months postpartum. Women in the high tertile had retained significantly more weight up through the sixth postpartum month. We conclude that a significant portion of maternal weight gain is likely to be retained, putting some women at risk of obesity.