Comparison of body fat mass changes during the third trimester and at one month postpartum between lactating and nonlactating Japanese women.

The purpose of the present study was to compare which parts of the body fat mass tended to increase during the third trimester and at 1 month postpartum between lactating and nonlactating Japanese women. This prospective study examined 49 healthy pregnant women in the third trimester, and at 1 month postpartum. Demographic data, including lactation status, were obtained from a self-administered questionnaire. Newborn information was obtained from hospital charts. Anthropometric data, including body fat mass, were measured by the bioelectrical impedance analysis (BIA) method in the third trimester, and at 1 month postpartum. At 1 month postpartum, 16 mothers (32.7%) were lactating and 33 (67.3%) were mainly feeding formula. There were no significant differences between the lactating and nonlactating women regarding their demographic data, energy intakes and body fat mass changes during the third trimester of pregnancy. The trunk fat mass change showed a significant difference (p = 0.008) between the third trimester and 1 month postpartum, after adjustment by age and parity using repeated measurement ANCOVA, in the lactating and nonlactating women. In conclusion, the total body fat mass and body fat mass in the trunk at 1 month postpartum was significantly greater in lactating women than in nonlactating women.