[Recommendations for immunohematological management of pregnancy. Working group: Fetal-maternal anti-red blood cells alloimmunization from the French-speaking Blood Transfusion Society].

Immunohematological (IH) monitoring during pregnancy is of critical importance for both fetal and maternal outcomes. For the fetus, it enables the Rh disease prevention, the diagnosis and the follow-up of fetal-maternal erythrocytes incompatibilities (FMEI), while for the mother, it allows anticipation of potential transfusion requirements. The diagnosis of FMEI relies on rigorously conducted IH surveillance, in compliance with the recommended schedule for anti-red blood cells antibody screening as defined by the French National Authority for Health (HAS), as well as with current regulatory frameworks (2018 regulatory order). In 2018, a working group was established within the French Society of Blood Transfusion (SFTS) with the objective of evaluating current practices in IH monitoring of pregnancies in France and subsequently developing more detailed recommendations to optimize patient management. Based on two national surveys-a questionnaire assessing laboratory practices and a registry of cases involving suboptimal management associated with inadequate IH monitoring-as well as a systematic review of the literature conducted according to the GRADE methodology, the working group formulated recommendations for IH monitoring in pregnant women that cover all the medical biology examinations process. Particular emphasis was placed on the following aspects: - The anti-red blood cells antibody screening schedule, including the recommendation to perform screening at six months of gestation, irrespective of the patient's D (RH1) status. - The utility of screening panels designed to detect the widest possible range of clinically significant alloantibodies associated with obstetric risk, ideally including Cw+ and Kpa+ red blood cells. - The indications for implementing quantification techniques beyond standard titration, notably anti-D microtitration and quantitative assays. - The importance of providing expert interpretative comments alongside laboratory results; in cases of fetal-maternal incompatibility. This includes specifying the risk of hemolytic disease of the fetus and newborn (HDFN) based on the specificity and concentration of maternal antibodies, as well as recommending appropriate monitoring intervals. - The procedures for timely and effective communication of results-particularly abnormal findings-to the sampling laboratory, clinicians, and/or transfusion services.