Preliminary results of the endometrial and ovarian response to luteal phase norgestrel

Luteal phase administration of dl-norgestrel, in doses of 10 mg to two groups of women with ovulatory cycles, did not significantly affect the length of the menstrual cycles, the duration of menses, or the endometrium whether given on a 5-consecutive day (group A) or 5-alternate day schedule (group B). Serum progesterone levels decreased in 9 of 11 patients in group A from a pretreatment level of 1431 ng/100 ml to 568 ng/100 ml and then to 419 ng/100 ml for the first and third treatment cycles, respectively; corresponding values for group B were 1149 ng/100 ml, 237 ng/100 ml, and less than 100 ng/100 ml, respectively. No adverse reactions were noted in any of the subjects; Papanicolaou smears remained class I, blood chemistry values showed no significant changes from pretreatment values, and no pregnancies occurred during treatment.