Serum estrogens and ovulation return in chronic users of a once-a-month injectable contraceptive.

ABSTRACT

To determine whether the long-term exposure to a monthly injectable contraceptive, containing dihydroxyprogesterone acetophenide 150 mg and estradiol enanthate 10 mg, induces significant changes on the serum estrogens profile and ovulation return in women, a study in chronic users was undertaken. Ovarian function was assessed for 3 months following a single injection of the contraceptive agent in a group of women (n = 7) who have been on this formulation for an average period of 6.7 years and in a non-user control group (n = 7). The serum concentrations of 17 beta-estradiol, estrone and progesterone were measured in samples drawn at regular intervals throughout the entire study. The endometrial bleeding pattern was recorded in all subjects. The results indicated that the post-injection serum estradiol maximum levels (exogenous peak) occurred significantly earlier (p less than 0.05) in chronic users as compared with the non-user control group. Baseline serum estrone concentrations were slightly higher in chronic users than those observed in the control group, while the values of serum 17 beta-estradiol did not exhibit significant differences among the two groups. Ovulation was documented within 60-90 days after injection in all subjects from both groups. A similar length of the first bleeding-free period was observed in all participants. The overall data provide evidence of a moderate increase of estrone, one of the still active metabolic conversion products of 17 beta-estradiol, in the sera of chronic users of this combined contraceptive without affecting its pharmacodynamics.

ABSTRACT

PIP The effects of longterm exposure to a monthly injectable contraceptive agent containing 150 mg of dihydroxy-progesterone acetophenide and 10 mg of estradiol enanthate on the serum estrogens profile and ovulation return were investigated in 7 women who had been taking this form of fertility control for an average of 6.7 years and 7 previous nonuser controls. Blood samples were taken immediately prior to injection and twice a week thereafter for a total of 3 months. Longterm users were injected 25-30 days after their previous injection, while the nonusers were injected during the early follicular phase of their menstrual cycle. Baseline serum estradiol concentrations were not significantly different between the 2 groups; immediately after injection, however, serum levels of estradiol increased rapidly to attain a maximum value of 314 in longterm users and 283 pg/ml in controls. The time required to reach maximum estradiol levels was significantly less in longterm users (4.2 days) compared with controls (6.3 days). Higher serum estrone levels were recorded at baseline in the chronically exposed women, although there were no significant differences between groups after 30 days. Ovulation was documented 60-90 days after injection in all subjects and endometrial bleeding patterns were the same in both groups. Overall, these data suggest that the slight increase in serum estrone levels associated with longterm use of this injectable contraceptive is not sufficient to produce prolonged ovarian and endometrial function impairment.