Purpose To determine the relationship between maternal lifestyle and obstetric and neonatal outcomes.

Methods and analysis This is a multicentre, prospective, cohort study including more than 5000 participants in 24 hospitals in 12 provinces from July 2017 to July 2018 in China. Maternal lifestyle (environmental exposures, diet, physical activity, sleeping, psychology and economics) and metabolic status will be collected by the electronic self-administered questionnaire at the first, second and third trimesters and 42 days postpartum, respectively. Obstetric and neonatal outcomes and metabolic status recorded by a clinical research coordinator. Descriptive statistics will be used to investigate the outcomes of maternal and newborn across China. Logistical regression and covariance analysis will be used to determine the relationship between maternal lifestyle and obstetric and neonatal outcomes. SAS statistical software will be used for data analysis.

Ethics and dissemination Permission for the study was obtained from Chinese Academy of Medical Sciences and Peking Union Medical College. Ethics approval was obtained from the Ethics Review Committee at Department of Scientific Research, Peking Union Medical College Hospital, Beijing, China. The results will be published in peer-reviewed journals or disseminated through conference presentations.

The participants were pregnant women who satisfied the following criteria: (1) ≥16 years old; (2) at 5-12 weeks' gestational; (3) able to complete the questionnaire; (4) permanent residents in the study locations; and (5) willing to sign the consent form.

only pregnant women at 5-12weeks gestationnal will be included in this study

More than 5000 pregnant women will be recruited from July 2017 to July 2018 during their routine antenatal check at the first trimester. Maternal lifestyle (environmental exposure, diet, nutrient, physical activity, sleep quality, psychology and economics) are collected by electronic self-administered questionnaire at the first, second, third and 42 days postpartum. A clinical research coordinator will record the metabolic status (pre-pregnancy BMI and GWG) and obstetric and neonatal outcomes will be recorded.