Link Found Between Sickle Cell Trait and Adverse Pregnancy Outcomes in Black Women

Sickle cell trait (SCT) is a genetic condition resulting from the presence of 1 abnormal hemoglobin gene and 1 normal hemoglobin gene. While SCT is generally considered benign, some reports suggest an association between SCT and adverse pregnancy outcomes (APOs). However, the evidence has been inconsistent.

A study published in Acta Obstetricia et Gynecologica Scandinavica sought to expose the existing gaps by conducting a retrospective analysis of a prospectively designed population-based cohort.

The cohort comprised self-reported non-Hispanic Black women from the UK Biobank (UKB). The SCT status of participants was determined based on the presence of the heterozygous Glu6Val mutation in the HBB gene. The researchers examined several APOs, including 4 previously reported SCT-associated outcomes: preeclampsia, bacteriuria, pregnancy loss, and preterm delivery (birth <37 weeks of gestation). Additionally, the study explored a broader spectrum of APOs related to pregnancy, childbirth, and the postpartum period.

Of the 4057 self-reported non-Hispanic Black women with pregnancy records in the UKB, 581 (14.32%) were carriers of SCT. The study confirmed the correlation between SCT and 2 of the 4 previously reported SCT-associated APOs (preeclampsia and bacteriuria). Notably, it demonstrated that SCT contributes substantially to these 2 APOs among SCT carriers and in the population of self-reported non-Hispanic Black women.

While the study provides valuable insights, it does carry several limitations. The relatively small number of SCT carriers due to the low percentage of self-reported Black women in the UKB may affect the interpretation of null associations, especially for rare complications like venous thromboembolism. Additionally, some reported associations may not be statistically significant after adjusting for multiple tests, as numerous tests were performed for both previously reported and novel APOs.

“Screening for SCT carriers in Black women and offering targeted prevention and intervention during pregnancy may reduce APOs and racial disparity in maternal care,” the researchers wrote regarding the implications of their study. “Confirmation of these findings in independent study populations is required,” they concluded.