Reference range for the pulsatility index ductus venosus Doppler measurement between 11 and 13+6 weeks of gestation in a Brazilian population

Objective: To establish reference range for the pulsatility index (PI) ductus venosus (DV) Doppler measurement between 11 and 13 + 6 weeks of gestation in a Brazilian population. Methods: A retrospective cross-sectional study was performed with 430 singleton pregnancies. The PI DV Doppler measurement was performed as routine during the first trimester screening. DV was identified by color Doppler and the pulsed Doppler gate was placed in the distal portion of the umbilical sinus. When at least three typical DV waveforms were obtained, PI DV was measured manually in one waveform. Polynomial regression was used to obtain the best fit using PI DV Doppler measurement and crown-rump length (CRL) with adjustments by the determination coefficient (R-2). 5th, 50th and 95th percentiles for the PI DV Doppler measurements at each gestational were determined. Results: The mean of PI DV Doppler measurement was 1.1 +/- 0.2 (range 0.8-3.7). The linear regression was the best fit: PI DV measurement = 1.288-0.0034*CRL (R-2 = 0.03). Conclusions: Reference range for the PI DV Doppler measurement between 11 and 13 + 6 weeks of gestation in a Brazilian population was established.