Pregnant patients who present with Rhesus (Rh) incompatibility—a common cause of hemolytic disease of the fetus and newborn (HDFN)—and a weak D phenotype can achieve good perinatal outcomes without receiving anti-D injection therapy, according to findings from a case report published recently in the Indonesian Journal of Obstetrics & Gynecology Science.
The case study described a 34-year-old woman who visited an Indonesian medical facility at 27 weeks’ gestational age (GA) to receive routine antenatal care. The patient had been recognized as being Rh-negative seven years earlier, while delivering her second child. She had not experienced any compatibility issues with her prior pregnancies. The woman’s husband, who is the father of her children, has the Rh-positive blood type with a Dd genotype, which is indicative of a 50% probability that the offspring will have an Rh-positive blood type.
The mother underwent laboratory testing, in which a negative Coombs test and a weak D phenotype were revealed. Up to 27 weeks’ GA in this current pregnancy, as well as in her prior two pregnancies, she had never received an injection of anti-D therapy. In fact, none of her pregnancies had been associated with the development of HDFN. Based on the results of ultrasonography, a well-developed 27-week GA fetus with no major congenital disorders was observed.
The patient was advised to return to the medical facility in one week for the administration of RhoD immune globulin (RhoGAM). Subsequent monitoring revealed that the mother’s other two children, who were aged seven years and nine years, remained in good health with no complications linked to Rh incompatibility.
Read more about the prognosis of HDFN
Treatment with RhoGAM or RhIVIG in pregnant patients
Alloimmunization, which leads to HDFN, is one of the major causes of fetal loss and mortality among RhD-negative mothers.
The prevention of Rh incompatibility is attainable with the administration of RhoGAM. Currently, RhoGAM is used for prevention of Rh incompatibility in an Rh-negative mother. Utilization of RhoGAM prevents the development of antibodies against Rh-positive blood.
The main use of Rh intravenous immunoglobulin (RhIVIG) is the prevention of sensitization, which involves the coating of fetal RBCs containing surface D antigens with antibodies. When alloimmunization is not present and an Rh-negative mother is carrying an Rh-positive fetus, RhIVIG can be prophylactically administered to the pregnant patient. RhIVIG can also be used prophylactically in women who have experienced an abortion or a fetomaternal hemorrhage.
Regional disparities exist in the prevalence of the RhD antigen, with a higher incidence reported among African populations and a lower occurrence among Asians.
The favorable perinatal outcomes of this mother’s children might be associated with the presence of a weak D phenotype. Notably, pregnant women with a weak D phenotype experience fewer D antigens Although these D antigens can nonetheless lead to Rh sensitization, they are not sufficient to result in serious complications in the fetus.
“[Rh] incompatibility in pregnant women with [a] weak D phenotype can have good perinatal outcomes without anti-D injection therapy,” the authors highlighted. “Administration of [a]nti-D injection remains a viable option to prevent subsequent Rh alloimmunization,” they concluded.
