Reference values for ductus venosus Doppler velocity indices between 11 and 13+6 weeks of gestation: A single center prospective study in Iran

Abstract

Background: This study aimed to investigate reference Doppler  elocimetry indices (DVIs) of the fetal ductus venosus (DV) during 11–13 + 6 gestational weeks.

Materials and Methods: In a prospective observation over referrals to a single tertiary care center in a 2?year interval, normal singleton  regnancies with fetal crown?rump lengths (CRLs) of 43–80 mm were examined by a single experienced sonographer for their DV pulsatility index (DVPI), DV resistance index (DVRI), and S?wave maximum velocity/A?wave minimum velocity (S/A ratio). Multinomial and quantile regression functions were used to analyze the effect of gestational age (estimated by CRL) on reference values (5th and 95th percentiles of the distribution in each gestational day/week). P < 0.05 was considered significant.

Results: Over a sample of 415 participants with a mean/median  estational age of 12 + 1 weeks, no significant correlations were found between the CRL and DVIs using multinomial regression functions (linear model best fitted for all [DVPI: B coefficient = 0.001, P = 0.235] [DVRI: B coefficient = 0.001, P = 0.287] [DV S/A: B coefficient = 0.010, P = 283]).
Quantile regression analyses of DVIs’ reference values were onsignificant across the CRL range except for the DVRI ([5th regression line: coefficient = ?0.004, P = 0.018] [95th regression line: coefficient = ?0.001, P = 0.030]).

Conclusion: Reference values for DVPI, DVRI, and DV S/A ratios were established as 0.80–1.39, 0.62–0.88, and 2.57–6.70, respectively. Future meta?analyses and multicenter studies are required to incorporate DV  VIs into an updated universal version of the practice.