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

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.

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.

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).

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.