Longitudinal reference values for ductus venosus Doppler in low-risk pregnancies

Area of Science:

• Perinatology
• Fetal Medicine
• Cardiovascular Physiology

Background:

• The ductus venosus (DV) is crucial for fetal circulation.
• Establishing normal hemodynamic parameters is vital for monitoring fetal health.
• Doppler ultrasound provides non-invasive assessment of fetal cardiovascular function.

Purpose of the Study:

• To determine normal ranges for fetal ductus venosus blood flow velocities and indices.
• To analyze changes in these parameters during the second half of pregnancy.
• To provide reference data for clinical evaluation of fetal well-being.

Main Methods:

• Doppler ultrasound examination of 60 healthy pregnant women.
• Measurements taken at 4-week intervals during the second half of pregnancy.
• Calculation of peak systolic velocity (PSV), peak diastolic velocity (PDV), maximum velocity during atrial contraction (VAC), S/A ratio, PIV, PLI, and VIV.

Main Results:

• Significant increases in PSV, PDV, and VAC observed between 20-23 and 28-31 weeks gestation.
• Values for PSV, PDV, and VAC stabilized from 28 weeks until term.
• Significant decreases in S/A ratio, PIV, PLI, and VIV noted in the same period, followed by stabilization.

Conclusions:

• Normal ranges for fetal ductus venosus blood flow parameters have been established for the second half of pregnancy.
• Specific patterns of velocity increase and index decrease followed by stabilization are characteristic of normal fetal development.
• These findings support the use of DV Doppler in routine antenatal surveillance.