The association between fetal Doppler and uterine artery blood volume flow at term of pregnancy: a pilot study.

Purpose: To investigate the relationship between uterine artery blood volume flow and fetal doppler indices at term of pregnancy. 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 an accurate ultrasound scan until a week before the birth. Uterine artery (UtA) diameter and UtA volume blood flow was estimated were recorded. The volume of each artery was summed to obtain the total uterine artery volume blood flow (QUtA). Umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV) and cerebroplacental ratio (CPR) foetal doppler indices were evaluated. Linear regression analysis was performed to investigate the relation of the QUtA with the fetal Doppler indices. Results: 49 pregnancies were included. 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 labour and fetal outcomes.