RHD and alloimmunization: Of retrospective studies with pregnant individuals (n = 12), five included Rh-negative pregnant individuals with obstetric history of RhD alloimmunization [16, 20, 22, 25, 33], four studies included all Rh-negative pregnant individuals with Rh incompatibility attending reference centers [15, 19, 23, 24], two studies included pregnancies with severe RhD alloimmunization receiving IUT [27, 31], and one identified positive alloantibody screens [18].