UTERINE ARTERY VELOCIMETRY AND SPONTANEOUS PRETERM DELIVERY

Objective: To evaluate if idiopathic spontaneous preterm delivery is associated with abnormal uteroplacental circulation, as assessed by Doppler velocimetry. Methods: 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. Results: 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. Conclusion: 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.