Severity of sleep-disordered breathing improves following parturition.

STUDY OBJECTIVE Changes in sleep-disordered breathing associated with late pregnancy have not previously been systematically investigated; however, a number of case reports indicate exacerbation of obstructive sleep apnea in late pregnancy, often in association with maternal hypertension. We aimed to compare the severity of sleep-disordered breathing and associated maternal blood-pressure responses in late pregnancy with the nonpregnant state. DESIGN Case-controlled, longitudinal study of sleep-disordered breathing during late pregnancy and postpartum. STUDY PATIENTS Ten women referred for suspected sleep-disordered breathing during the third trimester of pregnancy. INTERVENTIONS None. MEASUREMENTS AND RESULTS Full overnight polysomnography and continuous systemic blood pressure were measured during the third trimester of pregnancy and 3 months following delivery. Parameters of sleep-disordered breathing, including apnea hypopnea index and minimum overnight arterial oxyhemoglobin saturation, were compared between antenatal and postnatal studies. An improvement in both apnea-hypopnea index and minimum arterial oxyhemoglobin saturation occurred consistently in all subjects postnatally. In non-rapid eye movement sleep, mean apnea-hypopnea index was reduced from 63 +/- 15 per hour antenatally to 18 +/- 4 per hour postnatally (P = .03), and in rapid eye movement sleep, from 64 +/- 11 per hour to 22 +/- 4 per hour (P = .002). Minimum arterial oxyhemoglobin saturation was increased from 86% +/- 2% antenatally to 91% +/- 1% postnatally (P = .01). Arterial blood-pressure responses to apnea peaked at 170 to 180 mm Hg antenatally, while they only peaked at 130 to 140 mm Hg postnatally. CONCLUSION This study indicates that late pregnancy may be associated with increased severity of sleep-disordered breathing and associated blood-pressure responses.