Pregnancy bleeding during second and third trimester: Is the Kleihauer-Betke test really useful?

To evaluate the usefulness of the Kleihauer test in pregnant women presenting with bleeding during the second and third trimesters.

Retrospective, single-center study.

French tertiary university center affiliated with the National Reference Center for Perinatal Hemobiology (CNRHP).

Pregnant women between 15 and 42 weeks of gestation (WG) who presented with bleeding between January 1 and December 31, 2019.

Clinical data, ultrasound findings, Kleihauer test results, and neonatal outcomes were analyzed. Additionally, all the Kleihauer test results from the CNRHP database among the same period were reviewed.

Positive Kleihauer test results, fetal heart rate monitoring abnormalities, Doppler ultrasound findings, and neonatal hemoglobin levels.

Among 463 women included, the Kleihauer test was performed in 169 cases (36.5 %), with no positive results. Prescription of the Kleihauer test was associated with gestational age at bleeding, active or recurrent bleeding and management. Fetal heart rate monitoring and Doppler ultrasound of the middle cerebral artery showed no significant abnormalities. Neonatal hemoglobin levels were collected for 316 newborns, with 4.4 % showing mild anemia (Hb < 13.5 g/dL), none requiring intensive care or transfusion. Among the 22,203 Kleihauer tests performed at CNRHP during the same period, 10.6 % (2,363/22,203) were conducted for bleeding and only 12/2,363 (0.5 %) were positive, none associated with adverse outcomes.

Systematic Kleihauer test in cases of bleeding during the second and third trimesters may have limited clinical utility. Further studies are needed to refine guidelines and optimize the management of these cases.