Uteroplacental circulation in patients with first-trimester threatened abortion

Objective: To assess uteroplacental circulation in patients with first-trimester threatened abortion with a living embryo. Design: Prospective, cross-sectional study. Setting: Tertiary care university hospital. Patient(s): Forty-nine patients with first-trimester threatened abortion and a living embryo and 129 women with singleton, low-risk, normally developing first-trimester pregnancies recruited as controls. Intervention(s): Transvaginal color Doppler ultrasound measurement of the peak systolic velocity and pulsatility index of the uterine arteries and the spiral arteries. Main Outcome Measure(s): Uteroplacental blood flow and pregnancy outcome. Result(s): There was a significant relation between gestational age and the peak systolic velocity and pulsatility index in the uterine arteries and between gestational age and the peak systolic velocity and pulsatility index in the spiral arteries in controls. There were no differences in any Doppler parameter assessed between the study group and the controls, even in those pregnancies that ended in spontaneous abortion. Conclusion(s): No apparent alteration occurs in the early uteroplacental circulation in patients with threatened abortion with a living embryo. The use of transvaginal color Doppler ultrasound is not helpful for predicting pregnancy outcome in these cases.