Comparison of uterine and spiral artery blood flow in women with unexplained and tubal infertility.

Objective: To evaluate the possible difference in uterine and spiral artery impedance to blood flow among women with unexplained and tubal infertility during spontaneous and gonadotropin-stimulated cycles.

Methods: We prospectively compared uterine and spiral artery pulsatility index and peak systolic velocity in a longitudinal study in women with either unexplained infertility (n = 20) or tubal infertility (n = 18). Measurements of uterine and spiral artery impedance were taken on days 11-12, 16-17 and 21-23 of the spontaneous cycle and on days 1, 5 and 10 during gonadotropin stimulation. In addition, measurements were taken on the days of oocyte pick-up and embryo transfer.

Results: A clinical pregnancy was achieved in 8/20 (40%) women with unexplained and 6/18 (33.3%) women with tubal infertility with in-vitro fertilization treatment. There were no differences in the uterine artery pulsatility index or peak systolic velocity during the spontaneous or the in-vitro fertilization cycle between the two groups. The impedance to blood flow in the uterine or spiral artery did not differ between women conceiving with in-vitro fertilization-embryo transfer and those who did not. However, the spiral artery pulsatility index on the 5th day of gonadotropin stimulation was significantly lower among women with unexplained infertility (0.96 +/- 0.25) compared to women with tubal infertility (1.24 +/- 0.30; P < 0.05), but on the other days of gonadotropin stimulation the spiral artery pulsatility index and peak systolic velocity were similar.

Conclusions: Impaired uterine or spiral artery blood flow is not an important factor in unexplained infertility.