(859) The Association Between Umbilical Artery End Diastolic Flow and Growth Velocity in Growth Restricted Fetuses

Friday, January 31, 2025

10:30 AM – 12:30 PM

Submitting Author and Presenting Author(s)

Mohammad Salameh, MD

Resident Physician
Mayo Clinic
Rochester, MN, United States

Coauthor(s)

JB

Joshua Brunton, DO

Maternal Fetal Medicine Fellow
Virginia Commonwealth University
Richmond, Virginia, United States
MB

Megan E. Branda, MS

Mayo Clinic
Rochester, Minnesota, United States
RT

Regan Theiler, MD, PhD

Mayo Clinic
Rochester, Minnesota, United States

Objective: Growth velocity is receiving increasing attention as a potential marker of fetal wellbeing. We aimed to investigate the relationship between umbilical artery diastolic flow, an established surveillance tool, and growth velocity.

Study Design: We conducted a retrospective cohort analysis of pregnant patients aged 18-45 years old who delivered between 2012 and 2022. Pregnancies with congenital abnormalities or multiple gestations were excluded. Growth velocity was defined as the difference between estimated fetal weight percentiles at 26-32 weeks and at 32-36 weeks divided by the time between ultrasound (percentile change per week). The last systolic to diastolic (S/D) ratio obtained between 32-36 weeks was chosen as the marker of umbilical artery end diastolic flow. A linear correlation model was used to investigate the relationship between S/D ratio percentile and growth velocity.

Results: 324 patients met inclusion criteria, and 74 patients had at least one umbilical artery study between 32-26 weeks. The range of growth velocity was -7.58-20.40/week (mean = 0.31/week). The range of S/D ratio percentiles was 2.46%-99.98% (mean = 63.70%); all patients had forward diastolic flow. There was a negative correlation between S/D ratio percentile and growth velocity with r=-0.31 (p< 0.01). This is shown in Figure 1.

Conclusion: Decreasing umbilical artery diastolic flow correlated with fetal growth deceleration over the weeks preceding the umbilical artery doppler exam. Additional studies are needed to determine whether using growth velocity combined with umbilical artery doppler studies improves prediction of fetal compromise and adverse neonatal outcomes.