Menopause predisposes women to sleep-disordered breathing (SDB) and sleep disturbances. Progestin has a potential to stimulate breathing and to induce sleep. Our goal was to test these effects objectively and to compare them with the effects of nasal continuous positive airway pressure (CPAP), which is the standard treatment of SDB.
In a placebo-controlled, double-blind, parallel-group trial, we investigated 34 postmenopausal women (17 in the placebo group and 17 in the medroxyprogesterone acetate [MPA] group) whose SDB had been treated with nasal CPAP for 6 months to 8 years prior to study entry. The 6-week trial included measurements with CPAP at baseline, after 14 days of placebo or MPA (60 mg daily), and after a 3-week washout. The participants discontinued their nasal CPAP therapy 1 week after baseline measurements and went on with study medication.
Two weeks after discontinuation of CPAP therapy, nightly oxygen saturation was sustained higher (P = 0.004) and arterial carbon dioxide tension was lower (P < 0.001) with MPA than with placebo. Carbon dioxide was also lower than during CPAP (P < 0.001), and this effect was sustained beyond 3 weeks after the cessation of MPA (P < 0.001). However, the apnea-hypopnea index of CPAP increased and sleep deteriorated similarly on MPA and placebo after withdrawal of CPAP therapy.
In postmenopausal women with SDB, MPA induces a long-lasting stimulatory effect on breathing without improving sleep quality or the apnea-hypopnea index.