Hepatic venous Doppler waveforms: changes in pregnancy.

A total of 75 fasted healthy normal volunteers were examined during various stages of pregnancy. Examinations were performed in a supine position using an Acuson 128 ultrasound scanner with a 3.5 MHz transducer. Doppler interrogation of the middle hepatic vein was made during quiet respiration by one of three examiners. The Doppler waveforms were subsequently assessed blindly by one of the authors and categorized as normal, damped, or flat. Between 12 and 20 weeks, the majority of patients had normal hepatic pulsatility (64%) with 20% damped and 16% flat. Between 20 and 30 weeks there was a significant change (p > 0.001) with 68% being flat, 20% damped, and only 12% normal. In the last 10 weeks of pregnancy the changes were more marked: 80% were flat, 12% dampened, and 8% normal. There was a profound change in hepatic venous pulsatility during pregnancy. Hepatic waveforms changed from their normal pulsatile nature to become completely flat with increasing gestation. These changes were more frequent and more marked the further gestation progressed.