Maternal serum alpha-fetoprotein levels higher in Black than White pregnant women, reveals research

The study, published in Clinical Chemistry, found higher maternal serum alpha-fetoprotein (AFP) levels in Black than White pregnant women, supporting the use of accounting for these differences in prenatal ONTD screening.

"AFP levels for pregnancies were higher in Black than White individuals (6 to 11 percent depending on gestational age)," the researchers reported.

"Similar screen-positive rates were observed for self-reported White and Black individuals in race-specific gestation age and maternal weight analyses at 0.74 versus 1.00 percent, respectively. However, the screen-positive rate was 2.4 times higher in Black than White individuals in race-agnostic analyses."

Maternal serum AFP levels are used in screening for open neural tube defects. Historical reports show that AFP levels and maternal weights are higher in self-reported Black than White individuals, however, recent studies question the need to account for these variables in screening. Glenn E Palomaki, Women & Infants Hospital and the Alpert Medical School at Brown University, Providence, RI, United States, and colleagues compared screening performance with and without accounting for race.

For this purpose, the researchers performed a retrospective analysis on deidentified prenatal screening records, including maternal weight and self-reported race of White or Black. For each group, gestational age-specific medians and weight-adjusted multiples of the median levels were separately calculated using a race-agnostic analysis. Outcome measures included the proportion of screen-positive results.

The following were the key findings of the study:

• 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% versus 1.00%, respectively.
• The use of race-agnostic analyses resulted in a screen-positive rate that was 2.4 times higher in Black than White individuals.

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

"Our results, together with existing professional recommendations and other current publications, endorse the continued self-reported race use in prenatal serum screening," the researchers concluded.

Reference:

Messerlian, G., Strickland, S. W., Willbur, J., Vaughan, C., Koenig, S., Wright, T., & Palomaki, G. E. Use of Maternal Race and Weight Provides Equitable Performance in Serum Screening for Open Neural Tube Defects. Clinical Chemistry. https://doi.org/10.1093/clinchem/hvae053