Comprehensive antenatal antibody screening conducted among all pregnant women is recognized as playing a key role in lessening the risks linked to development of hemolytic disease of the fetus and newborn (HDFN), according to findings from a case study conducted in India and reported in the journal Cureus.
The current case study describes a 29-year-old pregnant woman at 38+1 weeks gestational age. The patient presented with a history of multiple pregnancies and was scheduled to undergo an elective lower-segment cesarean section.
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The pregnant woman underwent testing prior to her planned cesarean section, at which time her blood cross-matching results were shown to be incompatible. Additional blood work revealed the presence of anti-Fya antibodies.
A female baby who weighed 6.06 lb was delivered. Initially, the newborn exhibited no signs or symptoms of severe fetal distress. Shortly after birth, however, elevated bilirubin levels were detected in the infant, which led to her being transferred to the neonatal intensive care unit and receiving double-surface phototherapy.
The baby’s bilirubin concentrations decreased to baseline levels but eventually increased once again. Thus, a second round of double-surface phototherapy was required at 72 hours following birth. At 96 hours after birth, the newborn’s bilirubin levels declined to below the baseline threshold of 11 mg/dL.
Continued monitoring of the baby’s bilirubin levels showed that they remained within safe limits. No evidence of any bilirubin-associated neurologic dysfunction was reported, and the baby was discharged.
How HDFN severity coincides with specific antibodies
The development of HDFN is frequently associated with maternal antibodies against fetal red blood cell (RBC) antigens, with anti-D antibodies being the most common cause. Other, less often reported antibodies, however, can be linked to HDFN as well. These less commonly reported antibodies include anti-Fya, which is from the Duffy blood group system.
It is of key importance to take into consideration these other RBC alloantibodies as potential causes of HDFN, as individuals with the disorder can present with varying degrees of severity. In fact, RBC antibodies implicated in HDFN can develop naturally, from undergoing a prior pregnancy or from receiving a previous transfusion.
In Western countries, the primary cause of HDFN is ABO incompatibility. In contrast, in many developing countries, Rhesus (Rh) incompatibility is a common cause of HDFN. Over the last decade, in addition to anti-D antibodies, instances of moderate to severe HDFN occurring in Asian countries have been linked to other alloantibodies.
There have been two antigens identified in the Duffy blood group system—Fya and Fyb. The frequency of Duffy blood group system antigens varies according to different patient populations. In the Indian population, prevalence of the Fya antigen is 87.4%, whereas prevalence of the Fyb antigen is 57.6%.
Anti-Fya antibodies are commonly associated with severe HDFN, which requires the use of intrauterine transfusions, exchange transfusions, and high-intensity phototherapy. These anti-Fya antibodies may result in fetal hydrops and stillbirth. Although this did not occur in the current case, it is key importance for parents to remain vigilant and schedule regular follow-up medical visits.
“Implementing…screening practices [early in pregnancy] can improve outcomes by preventing complications associated with undetected alloimmunization,” the authors stated.
