Alberta Blood Transfusion Information

When you need Rh immune globulin

What is Rh immune globulin?

Rh immune globulin (RhIG or WinRho) is a blood product that is given when you’re at risk of forming antibodies. Antibodies are proteins your body makes to protect itself when it reacts with something that it doesn’t recognize.

These antibodies can form with:

pregnancy
a miscarriage
an abortion
an amniocentesis or chorionic villous sampling (CVS)
trauma (such as a car accident) during pregnancy
a blood transfusion

What does it mean to be Rh(D) negative?

There are 4 different blood types (A, B, AB, and O). There’s also an antigen called the Rh(D) on red cells. If you have the Rh(D) antigen on your cells, you’re Rh(D) positive. If you don’t have the Rh(D) antigen on your cells, you’re Rh(D) negative.

Only about 15 out of 100 people are Rh(D) negative. Being Rh(D) negative has no effect on your general health but can cause problems during pregnancy.

How does being Rh(D) negative affect pregnancy?

If you’re Rh(D) negative, your body can make antibodies if your blood is exposed to Rh(D) positive blood. This can happen during pregnancy or with a blood transfusion.

If you’re pregnant, some of your baby’s blood may come in contact with your blood. This is normal. If this happens, antibodies can form.

If you’re pregnant and Rh(D) negative and your partner is Rh(D) positive, then your baby might be Rh(D) positive too. You’re then at risk for making Rh(D) antibodies.

What can happen to my baby if I have Rh(D) antibodies?

Antibodies can cross the placenta and cause a problem for your baby. This is called hemolytic disease of the newborn (HDN). HDN can cause:

low hemoglobin causing anemia (fewer red blood cells)
toxins in the blood causing jaundice (yellow skin and eyes)
brain damage
death

What can I do to lower the risk of HDN?

HDN can be prevented more than 9 out of 10 times if you’re Rh(D) negative with injections of Rh Immune Globulin (RhIG). In Canada, the product used is called WinRho.

When is RhIG given?

RhIG is given when you're Rh negative and:

you’re 28 to 32 weeks pregnant
when you deliver if your baby is Rh positive
you have certain tests, treatments, or procedures (such as amniocentesis or chorionic villous sampling) during your pregnancy
you have some kind of physical trauma or injury, such as a car accident
any Rh-positive blood transfusion during pregnancy

If I am Rh(D) negative, do I need RhIG every time I get pregnant?

RhIG is given with each pregnancy. It helps protect your baby in each of your pregnancies.

Once your body makes antibodies, they don’t go away. After these antibodies develop, the risk for your baby goes up in future pregnancies.

What are the risks of RhIG?

RhIG is a blood product. Steps are taken to make it safe.

All donors are tested for viruses (such as HIV, Hepatitis B, and Hepatitis C).
The product is filtered and treated to kill any viruses that may be present.

RhIG has been used in Canada since 1968 with very few serious effects reported. If you have questions, talk to your doctor or healthcare provider.

What if I choose not to get RhIG?

If you don’t get RhIG, there’s a 3 in 25 chance that your body will make Rh(D) antibodies that can harm your baby. Once these antibodies develop, the risk goes up for future pregnancies.

What are the side effects of RhIG?

Most people who get RhIG don’t have side effects. Rarely, RhIG can cause:

pain at the injection site
fever (temperature over 38.5 °C or 101.3 °F)
feeling weak and unwell (malaise)
a headache
an allergic reaction (such as hives) which is usually not bad and goes away quickly

Is there any other way to prevent HDN?

RhIG is the only way to prevent HDN caused by the Rh(D) antigen. If you have any questions or concerns, talk to your doctor or healthcare provider.

Current as of: January 9, 2026

Author: Transfusion Medicine Program, Alberta Precision Laboratories

This material is not a substitute for the advice of a qualified health professional. This material is intended for general information only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use.