An international panel of experts in fetal medicine, neonatology, and hematology have issued consensus recommendations on hemolytic disease of the fetus and newborn (HDFN) screening, diagnosis and management, according to a report recently published in the American Journal of Obstetrics and Gynecology.
The expert panel included over 100 experts from 25 countries. Each one answered different questions regarding critical issues in HDFN management and reached a consensus on optimal techniques for determining fetal blood type, alloantibody titer thresholds, and the use of intravenous immunoglobulin (IVIG).
The survey was conducted using the Delphi technique, which consists of gathering a panel of experts on a specific subject and providing them with a questionnaire on key issues. After a first round of questions that produces a preliminary result of consensus and non-consensus matters, the experts are informed about the results to correct outlier responses after a second round of questioning.
“The findings of this Delphi can be used to create a standardized approach in the monitoring and management of pregnancies and newborns affected by maternal alloimmunization, particularly related to aspects where clinical and research knowledge gaps exist,” the authors wrote.
Summary of recommendations
Over 70% of experts concluded that in pregnancies with a risk of or confirmed alloimmunization against the RhD, Kell, and Rhc antigen, the fetus should undergo cell-free DNA (cfDNA) testing to determine the risk of HDFN. Approximately 66% of experts agreed that pregnancies in which cfDNA testing determines no risk of HDFN require no further testing.
Most experts recommended that mothers with antibody titers over 16 undergo median cerebral artery (MCA) Doppler ultrasounds to rule out fetal anemia. Over 60% of respondents suggested performing weekly MCA controls from week 16 onwards.
Regarding the use of IVIG in pregnancies in which the mother had a history of HDFN in a previous pregnancy, there was consensus on administering it at 10 or 14 weeks of gestation. However, it should be stopped if fetal anemia arises.
Although current guidelines recommend starting MCA Doppler monitoring between weeks 18 and 20, some authors recommend starting after week 24. The expert panel recommended weekly monitoring starting on week 16 of gestation.
There was no consensus regarding the minimal gestational age for administering intrauterine blood transfusion, but most experts agreed that the maximal age should be 35 weeks and six days.
