Carbonic anhydrase activity in human cervical mucus and its response to various contraceptives regimes

Carbonic anhydrase activity is present in human cervical mucus throughout the normal menstrual cycle. Lowest activity occurs in the ovulatory phase. A similar pattern of activity is seen in the presence of either an 'inert' or copper-releasing intrauterine contraceptive device (IUCD). The overall levels of activity are not significantly altered by the presence of either type of IUCD. A cyclic pattern of activity is retained even though endogenous ovarian function is suppressed by combined oestrogen-progestogen oral contraceptives.