Uterine artery velocimetry and spontaneous preterm delivery.

Abstract

To evaluate if idiopathic spontaneous preterm delivery is associated with abnormal uteroplacental circulation, as assessed by Doppler velocimetry. The study was carried out on 417 women who had Doppler velocimetry performed between 25-36 weeks' gestation and were subsequently delivered vaginally. The systolic-diastolic ratio (S/D) was computed for the uterine and umbilical arteries, and the outcomes of pregnancies with spontaneous preterm and term deliveries were compared. Uterine artery S/D was significantly higher (P < .0001) in the 31 patients delivered preterm, whereas no significant difference was observed in the umbilical S/D. Abnormal values of uterine S/D were detected in 58.1% of the preterm group, independent of the gestational age at examination. No significant increase in S/D was observed in patients hospitalized for preterm labor who delivered subsequently at term. Spontaneous preterm delivery was associated with increased uterine S/D among both pregnancies with small for gestational age fetuses and those with appropriately grown fetuses. Preterm delivery is associated with modifications of uterine artery Doppler velocimetry, suggesting that impaired trophoblastic invasion of the placental bed may play a role in determining preterm delivery.