The effects of 6 months of combined hormone therapy with transdermal estradiol (0.05 mg/day x 21 days) and different oral progestogens (10 mg/day medroxyprogesterone acetate [MPA] in the last 12 days, 10 mg/day dihydrogesterone in the last 12 days, and 50 mg/day cyproterone in the first 10 days), on menopausal symptoms and hypothalamo pituitary-ovarian function were studied in normal perimenopausal women. The study included 38 perimenopausal women, aged 43-49 years, with regular cycles of 26-32 days in length and menopausal symptoms. Endocrine status was determined by assay of basal levels of gonadotropins (LH, FSH), E2, and P every week until menstrual bleeding, before and during the first month of therapy. Plasma levels of LH and FSH were suppressed in the first month of therapy while E2 had a mean value of 45 +/- 12 pg/ml. Ultrasound examination and low levels of P indicated a complete block of ovulation and hypothalamo-pituitary-ovarian activity. All women reported the disappearance of vasomotor symptoms and nocturnal sweating. Transdermal estradiol and oral progestogens were well tolerated. This study shows that combined hormone therapy with low doses of transdermal estrogen patches and different oral progestogens reduces menopausal symptoms and also safeguards against unwanted pregnancies in the perimenopausal period.