Genotyping to prevent Rh disease: has the time come?

Area of Science:

• Maternal-Fetal Medicine
• Genetics
• Immunology

Background:

• D-alloimmunization poses a risk during pregnancy.
• RhIg (Rhesus immunoglobulin) is administered to prevent D-alloimmunization.
• Accurate fetal RHD typing is crucial for targeted RhIg prophylaxis.

Purpose of the Study:

• To review the literature on noninvasive fetal RHD typing.
• To determine if fetal RHD typing can safely guide RhIg administration.
• To assess the efficacy of targeted RhIg prophylaxis based on fetal RHD status.

Main Methods:

• Review of current literature on noninvasive fetal RHD typing.
• Analysis of studies evaluating diagnostic accuracy of large-scale screening programs.
• Assessment of duplex real-time PCR for fetal RHD determination.

Main Results:

• Large-scale fetal RHD typing programs demonstrate high diagnostic accuracy in routine settings.
• Fetal RHD typing is reliable for guiding both antenatal and postnatal RhIg administration in European descent populations.
• Noninvasive methods are effective for targeted RhIg prophylaxis.

Conclusions:

• Fetal RHD typing can safely and cost-effectively guide RhIg decisions.
• Targeted RhIg administration based on fetal RHD status can prevent unnecessary treatments in up to 40% of cases.
• Routine cord blood serology can be omitted when noninvasive fetal RHD typing is implemented.