Changes in physical activity across pregnancy among Chinese women: a longitudinal cohort study

BACKGROUND: Sufficient physical activity (PA) during pregnancy is beneficial for a woman’s health; however, the PA levels of Chinese women at different pregnancy stages are not clear. The aim of our study was to investigate PA changes during pregnancy and the association of population characteristics with PA change among Chinese women. METHODS: Data were obtained from 2485 participants who were enrolled in the multicentre prospective Chinese Pregnant Women Cohort Study. PA level was assessed in early pregnancy (mean = 10, 5–13 weeks of gestation) and again in mid-to-late pregnancy (mean = 32, 24–30 weeks of gestation) using the International Physical Activity Questionnaire short form (IPAQ-SF). Sufficient PA (≥ 600 MET min/week) in early pregnancy and insufficient PA in mid-to-late pregnancy indicated decreasing PA. Insufficient PA in early pregnancy and sufficient PA in mid-to-late pregnancy indicated increasing PA. The associations between demographic, pregnancy and health characteristics and PA changes were examined by multivariable logistic regression. RESULTS: Total energy expenditure for PA increased significantly from early (median = 396 MET min/week) to mid-to-late pregnancy (median = 813 MET min/week) (P < 0.001), and 55.25% of the participants eventually had sufficient PA. Walking was the dominant form of PA. Women with sufficient PA levels in early pregnancy were more likely to have sufficient PA in mid-to-late pregnancy (OR 1.897, 95% CI 1.583–2.274). Women in West China and those in Central China were most and least likely, respectively, to have increasing PA (OR 1.387, 95% CI 1.078–1.783 vs. OR 0.721, 95% CI 0.562–0.925). Smoking was inversely associated with increasing PA (OR 0.480, 95% CI 0.242–0.955). Women with higher educational levels were less likely to have decreasing PA (OR 0.662, 95% CI 0.442–0.991). CONCLUSIONS: PA increased as pregnancy progressed, and walking was the dominant form of PA among Chinese women. Further research is needed to better understand correlates of PA change. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12905-021-01377-3.