Impact of Using Abdominal Circumference Independently in the Diagnosis of Fetal Growth Restriction

Abstract

Objective-Society for Maternal-Fetal Medicine guidelines for diagnosing fetal growth restriction (FGR) have broadened the definition to include abdominal circumference (AC) <10 th percentile for gestational age (GA) regardless of estimated fetal weight (EFW). We aimed to compare the ability of three definitions of FGR to predict small for gestational age (SGA) neonates and adverse outcomes.Methods-We performed a secondary analysis of a prospective cohort of patients who underwent assessment of fetal growth between GA of 26 and 36 weeks. We compared three definitions of FGR: EFW <10 th percentile; AC <10 th percentile; either EFW or AC <10 th percentile. The primary outcome was successful prediction of neonatal SGA. Secondary outcomes included a composite adverse neonatal outcome (CANO). We further compared these definitions of FGR using area under receiver operative curves (AUC) to measure their discriminatory abilities.Results-About 1054 women met inclusion criteria. Ninety-one (8.6%) had EFW <10 th percentile, 122 (11.6%) had AC <10 th percentile, and 137 (12.9%) had either EFW or AC <10 th percentile. SGA was seen in 139 (13.2%); CANO was seen in 139 (13.2%). Ability for detecting neonatal SGA was significantly better when the definition included both EFW or AC <10 th percentile compared to either variable independently. The AUC were: 0.74, 0.73, 0.69; P = .0003. There was no statistical significance in ability for predicting CANO (AUC 0.51, 0.51, 0.50; P = .7447).Conclusions-Addition of AC as a criterion for diagnosing FGR improves our ability to predict neonatal SGA compared to using EFW alone. All three definitions were poorly predictive of neonates at risk for adverse outcomes.

Neonatal Outcomes among Fetuses with an Abdominal Circumference <3rd %ile and Estimated Fetal Weight 3rd to 9th %ile Compared to Fetuses with an EFW <3rd %ile

“…9 10 Previous data examining overall EFW <10 %ile for prediction of SGA birth weight has reported much lower positive predictive values (PPVs) of 49.4 to 63.7%. 11 12 A secondary analysis of a prospective cohort study demonstrated a PPV of 55.5% for detection of SGA birth weight among fetuses with either an AC or overall EFW <10th %ile. 12 Our data likely demonstrate higher rates of SGA birth weight due to inclusion only of fetuses with EFW <3rd %ile or AC <3rd %ile with overall EFW 3rd to 9th %ile.…”

Intrauterine growth pattern in Butajira HDSS, Southern Ethiopia: BUNMAP pregnancy cohort

“…Different research also examined the ability of AC in detecting SGA and fetal growth restriction. They found that AC below the 10 th percentile can be used to diagnose FGR [ 26 , 27 ].…”

Is there an association between isolated sonographic abdominal circumference below the 10th percentile and placental vascular lesions?

“…Other alternative criteria for the definition of FGR include prenatal diagnosis of abdominal circumference below the 10th, 5th, or 3rd percentile 1 . Notably, there are several studies with conflicting results aiming to determine, in a low‐risk population, which of the ultrasound parameters would be the better parameter in predicting neonates with FGR, abdominal circumference below the 10th percentile, estimated fetal weight below the 10th percentile, 2 or combined measurements 3 . Nevertheless, it has been suggested that the definition of FGR may be too broad, leading to false‐positive diagnoses with small for gestational age (SGA) infants who are constitutionally small and healthy 3 …”

“…abdominal circumference below the 10th percentile, estimated fetal weight below the 10th percentile, 2 or combined measurements. 3 Nevertheless, it has been suggested that the definition of FGR may be too broad, leading to false-positive diagnoses with small for gestational age (SGA) infants who are constitutionally small and healthy. 3 In order to reduce adverse neonatal morbidity and mortality, accurate identification is important together with proper timing of delivering.…”

“…3 Nevertheless, it has been suggested that the definition of FGR may be too broad, leading to false-positive diagnoses with small for gestational age (SGA) infants who are constitutionally small and healthy. 3 In order to reduce adverse neonatal morbidity and mortality, accurate identification is important together with proper timing of delivering. Commonly, additional ultrasonic Doppler assessments, which reflect the condition of the growth restricted fetus, mostly in the early gestational period (<32 weeks of gestation), help the clinician to decide the proper time to deliver.…”