Objective To determine the level of moderate-to-vigorous physical activities (MVPA) and its relationship with gestational weight gains (GWG) in the second and the last trimesters of pregnancy. Methods A prospective study was conducted in Chengdu on 362 healthy pregnant women at the 24-28 gestation weeks who delivered a singleton. Demographic data and pre-pregnancy body mass were collected using a questionnaire. Weight gains at the gestation weeks of 24-28 and 32-36 were measured for the first two trimesters and the last trimester of pregnancy. The Denmark self-reported physical activity scale was used for measuring the duration and intensity of physical activities. Multiple linear regression models were established to determine the relationship between MVPA and GWG. Results The last trimester had lower average daily MVPA 〔（0.76±0.93) h〕 compared with the second trimester 〔（1.61±1.61） h, t=9.056, Pχ2=16.387, PPPP
