Objective/Hypothesis: The purpose of this study is to determine if parturients identified as high risk for obstructive sleep apnea (OSA; defined as an apnea hypopnea index \[AHI\] ≥5 events/hour) who are randomized to receive an unattended sleep study during early and late pregnancy (early = between 6 and 16 weeks; late = between 27 and 33 weeks) plus initiation of CPAP therapy if the AHI ≥5 events/hour and standard prenatal care have a decreased incidence of adverse pregnancy outcomes (defined as a composite variable which includes gestational hypertension, preeclampsia, eclampsia, gestational diabetes, preterm birth, low birth weight, or stillbirth) at the time of delivery when compared to a group who receives standard prenatal care only (no sleep study and CPAP initiation). At 8 to 12 months postpartum subjects in both groups will complete a sleep study.