Snoring, upper airway resistance syndrome, sleep apnea syndrome and obesity hypoventilation syndrome are all defined as sleep-disordered breathing. Many changes occur in the respiratory system and sleep physiology during pregnancy due to physical and hormonal causes. Functional residual capacity, total sleep time, rapid eye movement (REM) sleep and stage 3-4 non-REM sleep are reduced during the third trimester of pregnancy. Snoring is more prevalent in pregnant women than nonpregnant women. Snoring during pregnancy may be associated with pregnancy induced hypertension, preeclampsia, intrauterine growth retardation and low APGAR scores in infant. The prevalence of sleep apnea syndrome during pregnancy is unknown. All pregnant women, especially obese and preeclamptic were asked to possibility of sleep disordered breathing. In this review we summarized, first normal physiological changes of respiratory system and sleep during pregnancy, second maternal and fetal outcome of sleep disordered breathing and finally treatment of sleep disordered breathing in pregnancy.