(793) Fetal growth restriction: Does dating by ultrasound versus last menstrual period change the antepartum diagnosis?

Friday, February 10, 2023

10:30 AM – 12:00 PM

Objective: To determine if the antenatal diagnosis of fetal growth restriction (FGR) is resolved when the estimated delivery date (EDD) is determined by crown-rump length (CRL) on ultrasound instead of last menstrual period (LMP). Our secondary objective is to determine if FGR resolution is associated with being small for gestational age (SGA) by birth weight.

Study Design: In this retrospective chart review study, we identified patients with the antenatal diagnosis of FGR at a single institution from 3/1/2018-6/23/2022. Those with EDD determined by their LMP were then identified and their first trimester ultrasounds were reviewed to determine an alternate EDD by the CRL measurement. The ultrasounds that first detected FGR were then reviewed and the percentile for the estimated fetal weight or abdominal circumference was re-calculated based on the alternate EDD determined by CRL. The primary objective was to determine whether there was a resolution of antepartum FGR diagnosis based on this re-calculation. The proportion and 95% confidence interval of FGR resolution was computed. Birth weight and gestational age at birth were used to determine the presence of SGA. For our secondary objective, Pearson’s Chi-Square test was used to assess the association between resolution of FGR diagnosis and SGA.

Results: We identified 187 patients with FGR based on menstrual dating. Fifty-one patients were missing CRL data and were excluded, leaving 131 for analysis. We found that 53 (40%) of these had FGR resolution when we re-calculated the EDD by CRL (95% CI: 32%, 50%). Among those with FGR, 8 were missing a value for birth weight, for a total of 123 patients for analysis of the association between FGR resolution and SGA. Despite resolution of antenatal FGR diagnosis, the proportion of SGA infants did not differ; 38 (79%) with FGR resolution were SGA at birth and 60 (80%) without FGR resolution were SGA at birth (Table 1).

Conclusion: Although 40% of cases had resolution of antenatal FGR diagnosis by adjusting EDD based on by CRL, this resolution did not impact the proportion of infants who were SGA at birth.

Primary & Presenting Author(s)

Kea Alexa Moncada, MD (she/her/hers)
Staten Island University Hospital
Staten Island, New York, United States

Coauthor(s)

KB
Karen Beckerman, MD
Staten Island University Hospital
Bronx, New York, United States
JC
Jerel Chacko, MBA, MD
Staten Island University Hospital
Staten Island, New York, United States
SI
Stephanie Izard, MPH
Feinstein Institutes for Medical Research, Northwell Health
New York, New York, United States
CC
Codruta Chiuzan, PhD
Feinstein Institutes for Medical Research, Northwell Health
New York, New York, United States
GF
Gary Fruhman, MD
Staten Island University Hospital
Staten Island, New York, United States