Use of Maternal Race and Weight Provides Equitable Performance in Serum Screening for Open Neural Tube Defects

Abstract

Background: Maternal serum alpha-fetoprotein (AFP) levels are used in screening for open neural tube defects (ONTD). Historical reports show that AFP levels and maternal weights are higher in self-reported Black than White individuals, but recent reports question the need to account for these variables in screening. Our study compares screening performance with and without accounting for race.

Methods: Retrospective analysis was performed on deidentified prenatal screening records including maternal weight and self-reported race of White or Black. Gestational age-specific medians and weight-adjusted multiples of the median levels were calculated separately for each group and using a race-agnostic analysis. Outcome measures included the proportion of screen-positive results.

Results: Records for analysis (n = 13 316) had an ultrasound confirmed gestational age between 15 and 21 completed weeks, singleton pregnancy, and self-reported race. Race was Black for 26.3%. AFP levels for pregnancies in Black individuals were higher than in White individuals: 6% to 11% depending on gestational age. Race-specific gestational age and maternal weight analyses resulted in similar screen-positive rates for self-reported White and Black individuals at 0.74% vs 1.00%, respectively (P = 0.14). However, use of race-agnostic analyses resulted in a screen-positive rate that was 2.4 times higher in Black than White individuals (P < 0.001).

Conclusion: These data show that the historical method of accounting for maternal race and weight in prenatal screening for ONTD provides equitable performance. Using a race-agnostic methodology results in an increased screen-positive rate and a disproportionate rate of required follow-up care for individuals who self-identify as Black.