Contraction-based uterine artery Doppler velocimetry: novel approach for prediction of preterm birth in women with threatened preterm labor

Objective To evaluate whether uterine artery Doppler velocimetry during peak uterine contraction is a useful marker for the prediction of preterm delivery. Methods In this prospective cohort study, 172 patients admitted with preterm (24–35 weeks of gestation) uterine contractions were evaluated by uterine artery Doppler velocimetry during peak uterine contraction and common obstetric measures including the cervical length. For uterine artery Doppler velocimetry, flow velocity waveforms during peak uterine contraction (determined visually from the tocodynamometer) were recorded during three consecutive heart cycles, and the mean uterine artery pulsatility index was calculated. Results During the peak of contraction, the uterine artery pulsatility index was significantly higher in patients who delivered within 7 days than in the patients who did not deliver (p