Rhesus (Rh) factor (also called D-antigen) is an inherited protein found on red blood cells. If a person’s blood has the protein, they’re RhD positive. If not, they’re RhD negative. Normally, this doesn’t affect a person’s health, but it may cause complications during pregnancy if the pregnant person and fetus have incompatible blood types.
Currently, as a precaution, all pregnant people with RhD negative blood types receive an injection to prevent their immune system from developing antibodies that fight against their fetus’s blood type. If antibodies do develop, they don’t pose a risk to the first pregnancy, but future pregnancies are closely monitored. These steps aren’t necessary in pregnancies without RhD incompatibility. A blood test called noninvasive fetal RhD blood group genotyping (RhD genotyping) can look at fetal DNA in the pregnant person’s blood and see if the pregnancy is RhD incompatible.
This health technology assessment looked at how accurate, clinically useful, and cost-effective this genotyping test is for determining if a pregnancy is RhD incompatible to help guide care. It also looked at the budget impact of publicly funding the test and at the experiences, preferences, and values of patients and health care providers related to care for RhD incompatible pregnancies.
Read the full health technology assessment report for more information.