Abstract Objective This study aimed to examine prospective associations of different intensity levels and types of physical activity (PA) in early pregnancy with premature rupture of membranes (PROM) among Chinese pregnant women. Methods A total of 6284 pregnant women were included from the Tongji-Shuangliu Birth Cohort. Household/caregiving, occupational, sports/exercise and transportation activities during early pregnancy were investigated by the pregnancy physical activity questionnaire (PPAQ), and the diagnosis of PROM was ascertained during the whole pregnancy. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence interval (CI) for the associations between PA and PROM. Results Among the 6284 pregnant women, 1246 were identified to have PROM (19.8%). Women undertaking the highest level (3 third tertile) of PA during pregnancy appeared to have a lower risk of PROM [OR = 0.68, 95%CI 0.58–0.80) when compared to those at the lowest tertile of PA. Similarly, women with increased levels of light intensity activity, moderate-vigorous intensive, household/caregiving activity and meeting exercise guidelines during pregnancy were associated with reduced risks of PROM (OR = 0.69, 95% CI 0.59–0.81, OR = 0.70, 95% CI 0.60–0.82, OR = 0.62, 95% CI 0.53–0.73 and OR = 0.82, 95% CI 0.70–0.97, respectively). Conclusions High levels of PA of different intensities and PA of household/caregiving activities and meeting exercise guidelines during the first trimester were associated with a lower incidence of PROM. Trial registration The data of human participants in this study were conducted in accordance with the Helsinki Declaration. This study has been approved by the Ethics Committee of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China ([2017] No. S225). All participants provided written informed consent prior to enrollment. A statement to confirm that all methods were carried out in accordance with relevant guidelines and regulations.

BACKGROUND: We aimed to examine prospective associations between diff erent intensities and diff erent types of physical activity (PA) in early pregnancy and hypertensive disorders of pregnancy (HDP) among Chinese women.METHODS: A total of 6,820 pregnant women from the Tongji-Shuangliu Birth Cohort were included in this study. The pregnancy physical activity questionnaire (PPAQ) was used to assess PA, including household/caregiving, occupational, sports/exercise, and transportation activities in the first trimester of pregnancy. The diagnosis of HDP was collected, including gestational hypertension (GH) and preeclampsia (PE). Data were analyzed by unconditional multivariate logistic regression, and the odds ratio (OR) and 95% confidence interval (CI) were calculated.RESULTS: A total of 178 (2.6%) of the 6,820 women were diagnosed with HDP, of which 126 (1.8%) were GH and 52 (0.8%) were PE. Overall, we found no association between PA in early pregnancy and PE. A trend toward lower risk was found only among women with GH and among those with higher levels of moderate-to-vigorous intensity physical activity (MVPA) (adjusted OR 0.54, 95% CI 0.31-0.96). No association was observed between PA and HDP in early pregnancy, regardless of diff erent intensities or types of PA. CONCLUSION: MVPA in the first trimester is an influencing factor of HDP. Encouraging pregnant women to engage in MVPA in the first trimester may help to prevent GH.