Estrogen-progestogen once-a-month injectable contraceptives and serum prolactin

To assess the effect of hormonal monthly injectable contraceptives upon the serum values of immunoreactive prolactin (Prl), three groups of women of reproductive age exposed to different estrogen-progestogen injectable formulation for a minimum of one year were studied. The first group (n = 10) received dihydroxyprogesterone acetophenide 150 mg and estradiol enanthate 10 mg (DHPA/E2-EN), Group 2 (n = 21) received medroxyprogesterone acetate 25 mg and estradiol cypionate 5 mg (MPA/E2-C) and Group 3 (n = 19) was exposed to norethisterone enanthate 50 mg and estradiol valerate 5 mg (NET-EN/E2-V). A group of IUD users (n = 16) served as the control group. Serum Prl and 17 beta-estradiol (E2) concentration were determined in blood samples (0 and 15 min.) on days 0 (day of last injection), 10, 20 and 30 after last contraceptive injection. The results demonstrated a slight though not significant increase (p greater than 0.05) in serum Prl in the three experimental groups as compared with the IUD control group. This increase in Prl levels observed on day 10 post-last injection never exceeded the upper limits of the normal range (20 ng/ml). Overall, the data demonstrated that the chronic administration of these estrogen/progestogen once-a-month injectable contraceptives does not affect the Prl baseline secretion in women.