Emerging data now show that sleep disruption during pregnancy, such as sleep-disordered breathing, short sleep duration, and poor sleep quality, is associated with adverse outcomes such as maternal hypertension and possibly preterm birth and fetal growth restriction. Our large, prospective cohort studies have investigated maternal and fetal outcomes of sleep disruption and have shown that maternal snoring, particularly new-onset snoring during pregnancy, is strongly associated with gestational hypertension and pre-eclampsia. In addition, snoring was associated with an increased incidence of small-for-gestational age infants as well as operative delivery. We are currently investigating the impact of positive airway pressure (PAP) therapy on pregnancy outcomes in women with gestational hypertension and pre-eclampsia. Women who enroll on the trial undergo baseline polysomnography and a PAP therapy polysomnogram. They then use the intervention for the remainder of their pregnancy while we monitor 24-hour blood pressure and follow their pregnancy and delivery outcomes.