Objective: A prospective cohort study was conducted to investigate sleep status during the first and second trimester of pregnancy in pregnant women on adverse birth outcome, such as preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA). Design: Prospective cohort study. Setting: China. Population: Cases were singleton pregnant women aged 18-40 years from the prospective Tongji-Shuangliu Birth Cohort. Methods: Multivariable logistic regression models were used to analyze the associationof sleep status during the first and second trimester of pregnancy with adverse birth outcomes and generated the odds ratio (OR) and 95% confidence interval (CI). Main outcome measures: Birth outcomes. Results: Finally, 5,412 pregnant women were included in the analysis. In the multivariable model, compared with 8-9 hours/night, sleep less than 7 hours/night during second trimester increases the risk of PTB (OR: 1.80, 95% CI: 1.12,2.89), and the risk of PTB was decreased in pregnant women who slept ≥11 hours/night (OR: 0.53, 95% CI: 0.30,0.93). Sleep quality, napping and sleep changes in the first and second trimesters, and sleep duration in the first trimester were not statistically associated with PTB, LBW and SGA. Conclusions: Short sleep duration during pregnancy is associated with a higher risk of PTB, while longer sleep duration at night is associated with a lower risk of PTB. Sleep status during pregnancy was not associated with LBW and SGA. In order to reduce risk of adverse birth outcomes, sleep problems in pregnant women should be strengthened during pregnancy care.