Ventilatory response of humans to chronic contraceptive pill administration.
We assessed ventilatory responses of 8 women to chronic contraceptive pill administration. We also studied 5 non-pill-taking women to determine if our techniques were capable of detecting the known ventilatory changes in the luteal phase of the menstrual cycle. During the high-progestin phase, relative to the low-progestin phase, the pill group had a mean increase in slope of CO2 response of 0.78 litres/min/mm Hg, a mean decrease in resting PET(CO2) of 1.3 mm Hg, and no change in hypoxic sensitivity. The non-pill group had no change in slope of CO2 response, a mean decrease in resting PET(CO2) of 1.1 mm Hg, and no change in hypoxic sensitivity. We conclude that the contraceptive pills studied cause a slight hyperventilation that is probably mediated by a central mechanism, as no changes in peripheral response were detected.
D000328:Adult; D003276:Contraceptives, Oral / Q000494:pharmacology*; D005260:Female; D006801:Humans; D009640:Norethindrone / Q000494:pharmacology; D010100:Oxygen; D010313:Partial Pressure; D012119:Respiration / Q000187:drug effects*; D013997:Time Factors
D003276:Contraceptives, Oral; D010100:Oxygen; D009640:Norethindrone