Fetomaternal hemorrhage in threatened abortion

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Hematology

Background:

• Threatened abortion, characterized by vaginal bleeding before 20 weeks' gestation without cervical changes, is a common obstetric complication.
• Fetomaternal hemorrhage (FMH) involves the transfer of fetal blood cells into the maternal circulation, with potential implications for Rh sensitization.
• Early detection and management of FMH are crucial for optimizing pregnancy outcomes.

Purpose of the Study:

• To compare the incidence of fetomaternal hemorrhage in patients experiencing threatened abortion versus a control group.
• To evaluate the utility of the Kleihauer-Betke acid elution assay in quantifying FMH in early pregnancy.

Main Methods:

• A comparative study involving pregnant patients with threatened abortion (vaginal bleeding <20 weeks' gestation, no cervical dilation/tissue passage) and a control group undergoing elective pregnancy termination.
• Fetomaternal hemorrhage was assessed using the Kleihauer-Betke acid elution assay, with a positive threshold of ≥0.07% fetal cells.
• Exclusion criteria for controls included any history of antepartum bleeding.

Main Results:

• The Kleihauer-Betke test was positive in 11% of patients with threatened abortion.
• In contrast, only 4% of the pregnant control group showed a positive Kleihauer-Betke test.
• These findings indicate a significantly higher incidence of FMH in threatened abortion cases.

Conclusions:

• Patients presenting with threatened abortion exhibit an elevated incidence of fetomaternal hemorrhage.
• The Kleihauer-Betke assay is a valuable tool for detecting FMH in this population.
• Rho(D) immunoglobulin prophylaxis should be considered for Rh(D)-negative patients with threatened abortion to prevent alloimmunization.