Hemolytic Disease of the Fetus and Newborn Caused by Maternal Alloanti-Fy(a).

Hemolytic disease of the fetus and newborn (HDFN) is commonly attributed to maternal antibodies against fetal red blood cell antigens, with anti-D being the most frequent cause. However, other antibodies, such as anti-Fy from the Duffy blood group system, can also lead to HDFN, although they are less commonly reported. This case study describes a 29-year-old woman at 38+1 weeks of gestation, with a history of multiple pregnancies and a planned elective lower-segment cesarean section (LSCS). During pre-operative testing, her blood cross-matching results were incompatible, prompting further investigation, which revealed the presence of anti-Fy antibodies. The neonate was delivered with an APGAR (appearance, pulse, grimace, activity, and respiration) score of 8/10 and 9/10 at 1 and 5 minutes, respectively, and initially exhibited no signs of severe fetal distress. However, elevated bilirubin levels were observed shortly after birth, necessitating double surface phototherapy. This case shows the clinical significance of anti-Fy in HDFN. It highlights the critical role of comprehensive antenatal antibody screening for all pregnant women, to detect potentially significant alloantibodies early and guide appropriate management to mitigate the risks associated with HDFN.