Effect of repeated hyperbaric exposures on the menstrual cycle: preliminary study

Two healthy female volunteers were subjected to hyperbaric air pressure of 5 ATA comparable to 130 feet of sea water (fsw) for 20 min 7 or 8 times during their menstrual cycles (experimental cycles). During the experimental cycles hormone assays for follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, and testosterone were performed before and after each dive on alternate days between the 5th and 11th cycle days (follicular phase), daily during the time ovulation was expected to occur, and on alternate days during the luteal phase; these were compared with the same assays throughout control cycles, during which the subjects were not pressurized. Periodic pressurization produced no significant changes in hormone patterns; ovulation was not inhibited and menstrual periods were unchanged.