A preliminary study on the pattern of weight change from pregnancy to 6 months postpartum: a latent growth model approach

Abstract

There is a lack of comprehensive understanding about patterns of weight change from pregnancy to childbirth and beyond. We describe the trajectory of weight change pattern from pre-pregnancy to 6 months postpartum and examine demographical and perinatal variables that predict the weight change using the latent growth model (LGM). This study used a longitudinal design. The study participants were 120 women whose body weights were measured at eight time points. The adjusted mean pre-pregnancy weight was 52.57 kg. When the weight growth rate for 10-13 weeks of pregnancy and pre-pregnancy weight was set to 1, the body-weight change rate was 2.20 during the second trimester, 2.14 during the third trimester, -2.90 during the period from the third trimester to 2-3 weeks postpartum, -0.08 during the period from 2-3 weeks to 4-5 weeks postpartum, -0.37 during the period from 4-5 weeks to 11-12 weeks postpartum, and -0.65 during the period from 11-12 weeks to 24-25 weeks postpartum. On average, body weight increased 26.54% (13.95 kg) from pre-pregnancy to 36-39 weeks of pregnancy and body weight remained 6.26% (3.29 kg) higher at 24-25 weeks postpartum compare with pre-pregnancy. In terms of factors related to body weight, age was positively associated with pre-pregnancy body weight. Parity had a negative effect on the change of body weight. Women who had an increased change rate in body weight had higher newborn birth weights. We found that weight change from pregnancy to postpartum followed a pattern that could be specified using the LGM approach. The women retained more than 6% of weight at 6 months postpartum compared with their pre-pregnancy weight.