The course of pregnancy in a Rhesus-negative patient

Abstract

Feto-maternal isoimmunization is a complex phenomenon in which the maternal immune system produces antibodies directed against antigens present on fetal blood cells. A common example of feto-maternal immunization is Rh isoimmunization, which occurs when an Rh-negative mother is exposed to the blood of an Rh-positive fetus. Maternal-fetal Rh isoimmunization causes more than 160,000 perinatal deaths and 100,000 cases of disability each year. In order to reduce perinatal mortality and morbidity from this pathology, recent guidelines from the French Society of Obstetrics and Gynecology (CNGOF, 2017), the International Federation of Gynecology and Obstetrics (FIGO, 2021), and the Canadian Society of Obstetrics and Gynecology (SOGC, 2024) have revised the management of pregnancy in Rh negative patients. In line with these recommendations, blood type and Rh determination is part of the recommended early pregnancy screening, ideally at the first antenatal visit. In non-immunized Rh-negative pregnant women with an Rh-positive partner, a non-invasive prenatal test can be recommended: Rh determination based on fetal acellular deoxyribonucleic acid present in maternal blood. Routine administration of anti-RhD immunoglobulin prenatally (at 2834 weeks amenorrhea (SA) and postpartum (within 72 hours after delivery) to unimmunized patients with Rh-positive infants allows reduction of feto-maternal sensitization.