Fetal RHD Screening

Talk to your health-care provider to see if Fetal RHD screening is right for you. In Ontario, this test can be ordered by:

• doctors (such as family doctors, obstetricians)
• nurse practitioners
• midwives

If you don’t have a family doctor, you can still arrange this test through a walk-in clinic. Use Health811 to find walk-in clinics near you. 

Fetal RHD screening can be done as soon as you are 11 weeks pregnant. 

Your health-care provider will give you a requisition for this test.  Take your requisition to your local laboratory to have your blood drawn. The laboratory will then send your sample to Canadian Blood Services for testing.

Not sure where to get your blood drawn?  Use the following links to find a lab near you: 

Find a Specimen Collection Centre – Ontario Association of Medical Laboratories: OAML
AlphaLabs - AlphaLabs

Fetal RHD screening is publicly funded for pregnant people living in Ontario if you:

• are RhD negative
• do not have anti-D antibodies
• are pregnant with one baby (not twins or more)

Fetal RHD screening should NOT be done if you : 

• are RhD positive
• already have anti-D antibodies

Fetal RHD screening should also NOT be done if you:

• are carrying more than one baby (twins or more)
• started your pregnancy with more than one baby and one was lost (known as a fetal demise or vanishing twin)
• have a known RHD variant or weak D blood type
• have had a stem cell transplant in the past

In these situations, your health-care provider may recommend RhIG during your pregnancy.

Fetal RHD screening can be done after 11 weeks of pregnancy.  It is best to do the test as early as possible in case you need RhIG early in your pregnancy. The test results can help you and your health-care provider decide if you need RhIG.

Fetal RHD screening is used to find out if you baby is RhD positive or RhD negative.

·       During pregnancy, your baby's placenta releases small pieces of genetic material (known as DNA) into your blood. Fetal RHD screening uses a blood sample from you to look at this placental DNA to predict whether your baby is RhD negative or RhD positive.

      Illustration adapted from Genetic Counseling Aids, 7th Edition, Copyright 2020, permission for use
granted by Greenwood Genetic Center.

Results are usually ready within 10 business days and are sent to your health-care provider.
Talk to your health-care provider about how they plan to give you these results. 

Sometimes the test cannot give a result. This is called an "Invalid' or "Inconclusive" result.  Another blood sample may be requested to repeat the test, or it may be recommended to treat your pregnancy as if your baby is RhD positive and recommend RhIG treatment.

Learn more about Fetal Blood Type Screening Results & Next Steps

After delivery, a small blood sample will be collected from the umbilical cord to confirm your baby’s RhD status. The results may be used to guide your need for RhIG treatment after birth and may be shared with the testing laboratory for quality checks.