Postpartum blood flow velocity waveforms of the uterine arteries.

Uterine arterial velocity waveforms, recorded by pulsed Doppler technology, demonstrated a significant increase in vascular resistance after the first postpartum day until the fourth to sixth postpartum week. In patients with an isthmic postcesarean hemorrhage, partial placental retention and puerperal endometritis, the corresponding waveforms presented higher diastolic velocity components than was the case for normal puerperal courses, indicating that lower uterine vascular resistance might be associated with these complications.