RESUMO
The effects of short-term administration of levonorgestrel (LNG) at different stages of the ovarian cycle on the pituitary-ovarian axis, corpus luteum function, and endometrium were investigated. Forty-five surgically sterilized women were studied during two menstrual cycles. In the second cycle, each women received two doses of 0.75 mg LNG taken 12 h apart on day 10 of the cycle (Group A), at the time of serum luteinizing hormone (LH) surge (Group B), 48 h after positive detection of urinary LH (Group C), or late follicular phase (Group D). In both cycles, transvaginal ultrasound and serum LH were performed from the detection of urinary LH until ovulation. Serum estradiol (E2) and progesterone (P(4)) were measured during the complete luteal phase. In addition, an endometrial biopsy was taken at day LH + 9. Eighty percent of participants in Group A were anovulatory, the remaining (three participants) presented significant shortness of the luteal phase with notably lower luteal P4 serum concentrations. In Groups B and C, no significant differences on either cycle length or luteal P4 and E2 serum concentrations were observed between the untreated and treated cycles. Participants in Group D had normal cycle length but significantly lower luteal P4 serum concentrations. Endometrial histology was normal in all ovulatory-treated cycles. It is suggested that interference of LNG with the mechanisms initiating the LH preovulatory surge depends on the stage of follicle development. Thus, anovulation results from disrupting the normal development and/or the hormonal activity of the growing follicle only when LNG is given preovulatory. In addition, peri- and post-ovulatory administration of LNG did not impair corpus luteum function or endometrial morphology.
Assuntos
Anticoncepcionais/farmacocinética , Anticoncepcionais Pós-Coito/farmacocinética , Levanogestrel/farmacocinética , Adulto , Biópsia , Anticoncepcionais/administração & dosagem , Anticoncepcionais Pós-Coito/administração & dosagem , Endométrio/efeitos dos fármacos , Feminino , Humanos , Levanogestrel/administração & dosagem , Fase Luteal/sangue , Fase Luteal/urina , Hormônio Luteinizante/sangue , Hormônio Luteinizante/urina , Fatores de TempoRESUMO
OBJECTIVE: To assess the serum concentrations of estradiol (E2), estrone (E1), gonadotrophins, sex hormone-binding globulin, and lipids, and to determine degree of symptom relief after subcutaneous implantation of 25 mg estradiol in postmenopausal Mexican women. DESIGN: Fifteen postmenopausal, hysterectomized women participated in an open, observational study. Blood samples were obtained before implantation and at regular intervals during a study period of 24 weeks. Climacteric symptoms were evaluated by means of the Greene climacteric scale. Wilcoxon's test was performed on the paired results of pre-and postimplantation values. RESULTS: Serum concentrations of E2 obtained after implantation were fairly constant, remaining within the early follicular range for the entire study period of 24 weeks, and were associated with significant symptom relief. A physiological, premenopausal E2:E1 ratio was achieved. No significant metabolic changes occurred. Side effects were estrogenic in nature and no removal of implant was required. CONCLUSIONS: Subcutaneous implantation of 25 mg estradiol results in physiological, premenopausal estrogen concentrations in most women and is associated with considerable symptom relief without inducing significant adverse metabolic effects.