Background: Sleep disorder is one of the most common complaints of pregnancy that can lead to maternal and fetal complications. Objectives: The main purpose of this study is to investigate the correlation between sleep disorders of pregnancy and abortion. Methods: This study is conducted using a case-control method on 218 women in the age range of 18 -35 years old with singletonpregnancy passing their first or second pregnancy in Ahvaz, Iran. Continuous sampling was conducted on the basis of characteristics of the research unit. The case group (n = 109) included women hospitalized because of an abortion, and the control group (n = 109) consists of pregnant women above 22 weeks, who were referred to healthcare centers to get pregnancy cares. The data collection was done using a demographic questionnaire and pittsburgh sleep quality index (PSQI). Data analysis was performed using SPSS-22 and t-test for quantitative variables and Chi-Square for qualitative variables. Results: Obtained results from the study showed that there is a significant relationship between abortion and sleep duration (P = 0.000), subjective sleep quality (P = 0.000), sleep latency (P = 0.000), habitual sleep efficiency (P = 0.000), sleep disturbances (P = 0.000), daytime dysfunction (P = 0.000), and total valued of sleep disorder (P = 0.000). However, the correlation was insignificant in case of use of sleeping medication (P = 0.233). Conclusions: According to the obtained results, there is a significant correlation between sleep disorder and abortion. Therefore, training sleep health and suitable consultations during pregnancy would be effective in field of preventing abortion and with the aim of achieving to safe pregnancy.