Abstract: During pregnancy, sleep patterns of women alter significantly. The problems such as abnormal sleep duration and poor sleep quality are particularly prominent. Unhealthy sleep pattern increases the risk of adverse pregnancy outcomes. As the most common adverse pregnancy outcome, preterm birth is the leading cause of disease and death in newborns. Through literature study, we briefly described the sleep status of pregnant women, and summarized the relationship between preterm birth and sleep in terms of sleep duration and quality of sleep. Future researches should pay more attentions to sleep situation of pregnant women, and effective interventions should be developed to guide pregnant women to get healthy sleep.