Uterine activity and ductus venosus flow velocity patterns during the first stage of labor

Objective: To analyze the effects of uterine contractions on ductus venosus (DV) pulsatility during the first stage of labor. Methods: Twenty healthy women were examined. Measurements were taken at three stages of cervical dilatation (<4 cm, 4–7 cm and ≥8 cm) during and between contractions. Peak velocity during ventricular systole (S) and atrial contraction (A), pulsatility index for veins (DV PIV), ductus venosus index (DVI) and the S/A ratio were measured. Results: The DV was observed successfully in 16 cases. The mean S velocity did not change significantly (64 cm/s during and 65 cm/s between contractions). The mean A velocity decreased significantly from 35 cm/s measured between contractions to 29 cm/s during contractions (P<0.0001). The mean DV PIV and DVI were significantly higher during contractions (0.72 and 0.55) than between contractions (0.57 and 0.45) (P<0.0001). There were no significant differences in means between stages of cervical dilatation. Conclusion: Significant differences during and between uterine contractions can be observed in DV pulsatility during normal labor.