The association between fetal Doppler and uterine artery blood volume flow in term pregnancies: a pilot study.

Purpose: To investigate the relationship between uterine artery blood volume flow and fetal Doppler indices in term pregnancies.

Materials and methods: A prospective observational study in a tertiary-care university hospital was performed between December 2021 and May 2022. We included only term pregnancies that received accurate ultrasound scans until a week before the birth. The uterine artery (UtA) diameter and UtA volume blood flow were estimated and recorded. The volume of each artery was summed to obtain the total uterine artery volume blood flow (QUtA). The following fetal Doppler indices were evaluated: Umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), and cerebroplacental ratio (CPR). Linear regression analysis was performed to investigate the relationship between the QUtA and the fetal Doppler indices.

Results: 49 pregnancies were included. The UA pulsatility index (PI) analysis showed a significant association with QUtA (r2=0.40, p=0.01), demonstrating a decrease of the UA PI when the QUtA increased. The same relationship was noted between the UtA mean PI and QUtA (r2=0.41, p=0.005). A weak correlation between the newborn weight and the QUtA was also noted (r2=0.31, p=0.048), with an elevated newborn weight when the QUtA was high.

Conclusion: This study showed that UA, UtA PI, and birth weight seem to be linked to QUtA. QUtA had an inverse correlation with UA and UtA PI. In addition, increasing the QUtA showed a linear increase in fetal birth weight. These findings could be helpful in high-risk pregnancy management, but additional research is needed to identify how QUtA in the third trimester impacts labor and fetal outcomes.