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

Abstract

Objective: 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).

Design and subjects: This study used a longitudinal design. The study participants were 120 women whose body weights were measured at eight time points.

Results: 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.

Conclusions: 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.