Respiration during sleep in pregnancy.

Several changes in maternal physiology may profoundly alter sleep, especially during late pregnancy. Any condition that causes maternal hypoxemia will be worsened during sleep, particularly in the supine position. Although high circulating levels of progesterone increase respiratory drive during sleep, in at least some women this protective mechanism is insufficient to prevent sleep-disordered breathing and hypoxemia. The true incidence of sleep-disordered breathing during pregnancy remains unknown. Although many women report sleep disturbance during pregnancy, those with severe snoring, observed irregular breathing with sleep, or excessive daytime somnolence should be referred for clinical polysomnography. With few data thus far available, nasal CPAP would appear to be the treatment of choice. Given the possible consequences of sleep apnea for fetal outcome, any significant sleep-disordered breathing is probably an indication for treatment.