Maternal BMI changes from the prepregnancy to postpartum period are associated with postpartum cardiometabolic risk factors: a longitudinal study

PURPOSE: This study aimed at investigating the associations between the total body mass index (BMI) change at 3 or 4 years postpartum compared to the prepregnancy and cardiometabolic risk factors. METHODS: This longitudinal study included 1305 participants. Based on the total postpartum BMI changes, they were divided into < 0 units, 0-1.7 units, and > 1.7 units groups using the interquartile range. Multiple linear regression models were used to analyze the associations. RESULTS: Compared to the reference group, there was a progressive increase in the βcoefficient (βcoef) of homeostasis model assessment of insulin resistance (HOMA-IR) of cardiometabolic risk in the following groups: the '0-1.7 units' group with the 'overweight traj' [βcoef 0.33; 95% confidence intervals (CI) 0.22, 0.44)] or the 'obesity traj' [0.66; (0.45, 0.88)] and the '> 1.7 units' group with the 'normal traj' [0.33; (0.22, 0.44)], the 'overweight traj' [0.54; (0.41, 0.67)] or the 'obesity traj' [0.97; (0.79, 1.15)]. The same increasing trend of βcoef was also found in DBP, FPG, LDL, WHR, BF%. However, the '< 0 units' group with the 'low traj' [0.13; (0.06, 0.21)] and the '0-1.7 units' group with the 'low traj' [0.08; (0.03, 0.13)] had higher high-density lipoprotein cholesterol (HDL-C) level than the reference group. CONCLUSION: Women with a postpartum BMI gain > 1.7 units are positively associated with cardiometabolic risk factors, especially for those in the 'obesity traj' or 'traj D'. Conversely, women with a postpartum BMI loss > 0 units have negative association with cardiometabolic risk factors, especially for those in the 'low traj' or 'traj B'.