Effect of Race in the Diagnosis of Fetal Growth Restriction in a Multicultural Urban Population [A202

Abstract

INTRODUCTION: Despite significant differences in fetal growth curves based on maternal race/ethnicity, fetal growth restriction (FGR) continues to be defined by the Hadlock formula generated from a study involving 392 predominantly White pregnancies. Accuracy in FGR diagnosis is crucial to prevent iatrogenic preterm delivery and unnecessary antenatal surveillance and intervention. We sought to compare the diagnostic accuracy of FGR in fetuses classified by Hadlock criteria versus Eunice Kennedy Shriver National Institute of Child Health and Human Development racial/ethnic-stratified criteria in a multicultural urban population. METHODS: A retrospective recalculation of estimated fetal weight (EFW) and abdominal circumference (AC) in fetuses diagnosed with FGR over a 5-year period using NICHD race-specific fetal growth criteria was performed. FGR was defined as EFW or AC less than 10th percentile. Chi-square analysis was performed to evaluate the differential effects of recalculation across racial groups. RESULTS: A total of 384 pregnancies with FGR were identified in 147 (38.3%) Asian, 114 (29.67%) Hispanic, 111 (28.9%) Black, and 12 (3.3%) White mothers. Recalculation normalized growth in 64 (16.7%) pregnancies and was disproportionate, with the greatest effect in pregnancies of Black mothers (29, 26.1%), followed by Hispanic mothers (17, 14.9%) and Asian mothers (18, 12.2%) (P=.01). CONCLUSION: Application of NICHD race-specific criteria reversed the diagnosis of a substantial number of FGR pregnancies, with the greatest reversal seen in pregnancies of Black mothers. More research is needed to evaluate the neonatal and long-term outcomes of fetuses misdiagnosed as FGR based on the old growth standards, as iatrogenic preterm delivery and steroid administration carry potential morbidity later in life.