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Rh Factor Incompatibility


Rh (rhesus) factor incompatibility is a condition that occurs when a mother is Rh negative (Rh-) and her baby is Rh positive (Rh+). Rh factor is a protein found on red blood cells. You are Rh+ if you have this protein and Rh- if you do not have it. Rh incompatibility usually has little effect on your first pregnancy, but can cause problems with future pregnancies.


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  • Blood tests: These check your blood type to see if you have antibodies to Rh factor. Blood tests to check the father's blood type and Rh factor may also be done.
  • Fetal blood sampling: This test may be done to check your baby's blood type and risk of anemia. Healthcare providers take a sample of your baby's blood from the umbilical cord. With an ultrasound to guide them, a needle is put through your skin, into your uterus, and into the umbilical cord.
  • Fetal biophysical profile: A fetal biophysical profile is a test that combines the nonstress test and a special ultrasound of your unborn baby. The nonstress test measures changes in your baby's heartbeat during movement. The ultrasound will show your baby's movement, how his muscles are working, and the amount of fluid around him. It will also show if your baby's breathing muscles are working.
  • Ultrasound: This test uses sound waves to show pictures of your baby inside your uterus. Healthcare providers can learn the age of your baby and see how fast he or she is growing. The movement, heart rate, and other organs of your baby can be seen. Your placenta (tissue in the womb connecting the mother and baby) and amniotic fluid may be checked. A Doppler ultrasound may be used in place of an amniocentesis to see the blood flow in your baby's body. Healthcare providers may use this test to check if your baby has anemia.
    Pregnancy Ultrasound
  • Amniocentesis: This is a procedure to take a sample of the amniotic fluid that surrounds your baby in the uterus. This procedure is used to look for problems with your baby. Healthcare providers use a needle, guided by an ultrasound, and remove a small amount of fluid from your baby's amniotic sac.


You will not need treatment for Rh incompatibility problems, but your baby might. He or she may need to be delivered early. He or she may also need any of the following:

  • Phototherapy: This is done to help reduce jaundice.
  • Blood transfusions: Blood transfusions may be given through the umbilical cord and after birth to treat severe anemia.
  • Immunoglobulins: This is an injection of antibodies to help reduce the destruction of red blood cells.


If Rh immune globulin shots are not given, Rh antibodies may form and put your baby or next pregnancy at risk. Your baby may have severe anemia and need blood transfusions. This may cause bleeding, allergic reactions, or infections. Even with treatment, your baby may have brain damage. Rh incompatibility may be life-threatening to your baby.


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Learn more about Rh Factor Incompatibility (Inpatient Care)

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