Utero-ovarian blood flow characteristics of pituitary desensitization

Background: Down-regulation in assisted reproduction treatment cycles is monitored by suppression of ovarian/pituitary hormones and/or measurement of endometrial thickness. Methods: This prospective longitudinal study reports on utero-ovarian characteristics of pituitary desensitization. A total of 75 patients were recruited; 32 had IVF treatment, 20 frozen-thawed embryo transfer cycles and 23 patients were recipients of donated oocytes. All received early follicular-phase down-regulation and had colour flow Doppler velocimetry of the utero-ovarian arteries ≤3 days before the start of menses and after 21 days of gonadotrophin-releasing hormone (GnRH) analogue treatment. Ovarian volume, endometrial thickness, pituitary and ovarian hormone concentrations were recorded at each scan. Results: Significant changes (P < 0.05) were noted in these and utero-ovarian vasculature during the down-regulation period, with good correlation between resistance index and oestradiol estimations. Neither the type of GnRH analogue nor age influenced the changes in utero-ovarian blood flow. Ovarian artery resistance index was the best Doppler predictor for pituitary suppression and a mean discriminatory cut-off value of 0.867 ± 0.025 was found to have the highest specificity and positive predictive value. Conclusions: This study has, for the first time, defined cut-off values for satisfactory pituitary suppression with high positive predictive value and specificity in an early follicular phase long protocol of GnRH analogue down-regulation using colour flow Doppler.