Sleep-disordered breathing and nocturnal oxygen desaturation in postmenopausal women.

Twenty postmenopausal women were monitored for disordered breathing (apnea and hypopnea) and oxygen desaturation during one night's sleep. These women were compared with 18 premenopausal women previously reported to have a low incidence of sleep-disordered breathing and nocturnal oxygen desaturation. Twelve of the 20 postmenopausal women had 102 episodes of sleep-disordered breathing and 118 episodes of oxygen desaturation, compared with only six episodes of apnea in two premenopausal women (P less than 0.01). Premenopausal women did not become desaturated. Of the postmenopausal women, 11 became desaturated; and in five of them saturation decreased to less than 85 per cent. Duration of sleep, and increased age and weight: height ratios, correlated significantly with the incidence of desaturation (P less than 0.01--P less than 0.05). Postmenopausal women resemble men with respect to disordered breathing during sleep and nocturnal oxygen desaturation. Protection from these sleep events in premenopausal women might be afforded by the respiratory stimulant effects of circulating progesterone.