RhD 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 an RhD negative blood type receive an injection to prevent their immune system from developing antibodies that fight against their fetus because of its blood type. If antibodies do develop, they don’t pose a risk to the first pregnancy, but future pregnancies are closely monitored. But the injections and monitoring 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.

The assessment was conducted in collaboration with the Canadian Agency for Drugs and Technologies in Health (CADTH). CADTH completed a rapid review of the qualitative evidence of patient preferences.