Pregnancy and the postpartum period are associated with significant changes in sleep architecture and the subjective quality of sleep. These changes are caused by the many physiologic changes that occur during pregnancy (eg, altered hormone levels, increased urination at night, changes in body size) and post partum, especially with a newborn to tend. Although most women negotiate the disruption to their sleep very well, others may experience such severe disruption to sleep that it compromises their physical well-being and mental health. Physicians providing care for pregnant women must inquire about sleep patterns; if a woman is reporting significant difficulty coping with the disruption, a thorough history should be taken. Primary sleep disorders are common in pregnancy and further investigation and treatment may be warranted.