The temperature, pH, and partial pressure of oxygen in the cervix and uterus of women and uterus of rats during the cycle.

Changes in the temperature, pH, and partial pressure of oxygen (PO2) in the cervical canal and cavum uteri were measured in women with or without an intrauterine device and in the uteri of rats throughout the cycle. Only the PO2 exhibited significant variations, rising during the ovulatory phase in both cervices of women and uteri in rats. It is speculated that the rise in PO2 is related to the function of these organs as reservoirs for spermatozoa.