Doppler analysis of uterine blood flow changes in spontaneous and medically induced menopause

The aim of this study was to compare the uterine blood flow variations induced by chemical castration and spontaneous menopause. Thirty infertile patients were studied in the early follicular phase (day 5-7) and then treated with gonadotropin releasing hormone agonists (GnRH-a). On day 25 from GnRH-a injection, the suppressive effect was checked. The values obtained were compared with those found in 18 postmenopausal women (menopause < 5 years). All the subjects underwent transvaginal ultrasonography, Doppler analysis of uterine arteries, hormonal assay and evaluation of hematological and biochemical parameters. In all infertile patients, the GnRH-a suppressive effect was shown at the 25th day from the injection. Endometrium thickness decreased from 0.6 +/- 0.1 mm to 0.3 +/- 0.1 mm (p < 0.05) and the pulsatility index increased from 2.52 +/- 0.31 to 3.02 +/- 0.25 (p < 0.05). The plasma estradiol level fell from 48.2 +/- 4.4 pg/ml to 13.6 +/- 7.9 pg/ml (p < 0.05). No other hormonal and biochemical parameters were significantly modified by GnRH-a. In postmenopausal women, the values of the studied parameters were similar to those found in the infertile GnRH-a-suppressed patients. These data show that GnRH-a induces vascular modifications similar to those induced by early post-menopause and that both are probably exclusively related to hypoestrogenism.