May Lee Tjoa, PhD, Senior Global Medical Affairs Leader: Nipocalimab and Maternal-Fetal Immunology at Johnson & Johnson, discusses data on hemolytic disease of the fetus and newborn (HDFN) from the 2025 ISUOG World Congress on Ultrasound in Obstetrics and Gynecology.
HDFN is a rare condition characterized by the destruction of fetal red blood cells due to maternal-fetal blood group incompatibility. The condition may occur in persons with Rh or ABO blood types. Rh incompatibility usually affects subsequent pregnancies due to maternal sensitization that occurs in the first pregnancy. This leads to more severe complications such as intrauterine hydrops fetalis in later pregnancies. ABO incompatibility can impact the first pregnancy due to preexisting maternal antibodies. Symptoms of disease in newborns include lethargy, jaundice, hepatosplenomegaly, and signs of hydrops fetalis.
There are currently no approved therapies for the treatment of HDFN. Pregnancies affected by severe HDFN may need repeated intrauterine transfusions (IUTs), and/or invasive surgical procedures that may be associated with increased rate of fetal mortality and premature birth. Below are summaries of three studies presented at the World Congress highlighting the need for improved therapy options for this rare condition.
Outcomes of intrauterine transfusion for the treatment of Hemolytic Disease of the Fetus and Newborn
The objective of this study was to evaluate outcomes of IUT for the treatment of severe HDFN in antenatal, perinatal, and infancy periods in 120 pregnancies. On average, each pregnancy underwent 2.9 IUTs and the gestational age at first IUT was 28 weeks.
Maternal complications related to infection from IUTs were uncommon but in 13% Cesarean section was performed within one day of an IUT. Additionally, preterm premature rupture of membrane, preterm birth, and Cesarean section delivery were elevated compared to the general pregnant population. More than two in three infants required admission to the NICU and more than half required phototherapy or transfusion treatment in the first 30 days of life.
HDFN diagnoses and symptoms, cardiac disorder, infection diagnosis, and respiratory diagnosis were evaluated in infants with IUT and compared to those from the general pregnant population. HDFN diagnoses and symptoms as well as cardiac disorders were more common in infants with antenatal IUT. Infection and respiratory diagnoses were balanced in both cohorts.
All-cause inpatient healthcare resource utilization and direct costs in children affected by hemolytic disease of the fetus and newborn in Sweden
The objective of this study was to quantify inpatient healthcare resource utilization (HCRU) and direct costs in children treated for HDFN in Sweden. Results showed that of 14,519 liveborn children, 50% were identified to have HDFN and 27% received HDFN treatment. IUTs were used as treatment in 8%, postnatal transfusion in 31%, and phototherapy in 90%. Of these patients with HDFN, greater HCRU and inpatient direct costs in the first year than those without HDFN were observed, especially those treated with IUT and transfusion. In patients who received postnatal transfusion and not IUT, greater yearly inpatient HCRU and costs persisted beyond the first year into preschool years.
Qualitative patient experiences of fetal and neonatal alloimmune thrombocytopenia (FNAIT): diagnostic and treatment challenges
FNAIT is a rare and potentially life-threatening alloimmune condition characterized by a pregnant person’s immune system developing antibodies against fetal or newborn platelet antigens, leading to thrombocytopenia. An analysis of patient experiences with the disease has highlighted challenges for patients and caregivers.
Due to its complex diagnostic journey, patients note feelings of confusion and fear surrounding the unknown implications of the disease. This illustrates a great unmet need within the community for better understanding of diagnosing and treating FNAIT. Additionally, work needs to be done in better relaying information to patients.
For more information, click here.
To learn more about HDFN, FNAIT, and other rare hematologic conditions, visit https://checkrare.com/diseases/hematologic-disorders/