FURTHER STUDIES ON THE EFFECT OF ORAL CONTRACEPTIVES ON ENDOCRINE FUNCTION WITH SPECIAL REFERENCE TO LUTEINISING HORMONE EXCRETION

ABSTRACT Serial assays of luteinising hormone (LH) and pregnanediol in urine have been performed in four women during and following long term therapy with oral contraceptives. One subject was treated with a progestogen-oestrogen mixture, another with a progestogen alone and two with a sequential regime. In three subjects there was definite evidence for the resumption of ovulation in the first post-treatment cycle; in the fourth the evidence was less clear cut. None of the patients showed suppression of urinary LH activity as a result of medication, and in all four the fiducial limits of individual assays in the treatment and post-treatment cycles overlapped to a considerable extent. One woman receiving sequential therapy showed a midcycle LH peak in the post-treatment but not in the treatment cycle. These findings are compatible with the view that long term therapy with oral contraceptives does not produce any deleterious effects on pituitary gonadotrophic function. In one subject the short term effect of chlormadinone acetate administered continuously in low dosage was investigated. The compound produced little effect on either LH or oestrogen output, but may have inhibited ovulation as judged by urinary pregnanediol assays.