You're Pregnant and
You're Rh-negative

Pregnancy is a very exciting time. This is also the first time most women learn their blood type. You just learned that you are Rh-negative and you probably have a lot of questions like, “What does this mean for me and my baby?”

Understanding your blood type

Rh is the abbreviation for rhesus, which is the name of one of many different blood group systems in the body

  Rh-positive people have the Rh antigen (also called rhesus factor or D antigen) on the surface of their red blood cells
  Rh-negative people do not have the Rh antigen on the surface of their red blood cells

What does being Rh-negative mean for you and your baby?

During pregnancy, it is normal for a small amount of the baby's blood to enter the mother's bloodstream.

  • When an Rh-negative mother carries an Rh-positive baby, and some of the baby’s blood enters the mother’s bloodstream, this is called Rh-incompatibility.
  • The mother’s immune system sees the baby’s red blood cells as “foreign” and will try to eliminate them as invaders.

Rh-incompatibility usually does not affect the mother’s first baby, but once she has produced an immune response (called “Rh-sensitization”), all future Rh-positive babies are at risk for developing hemolytic disease of the fetus and newborn (HDFN).

For the newborn, HDFN is a serious condition that may cause anemia, jaundice, and in severe cases, heart failure and possible brain damage. 

Since RhoGAM's introduction in 1968, the incidence of Rh sensitization has decreased dramatically1

 Reference: 1. Hartwell EA. Use of Rh immune globulin. ASCP practice parameter. Am J Clin Pathol. 1998;110:281-92.



RhoGAM® Ultra-Filtered PLUS [Rho(D) Immune Globulin (Human)] (300 μg), is a prescription medicine given by intramuscular injection that is used to prevent Rh immunization, a condition in which an individual with Rh-negative blood develops antibodies after exposure to Rh-positive blood. MICRhoGAM® Ultra-Filtered PLUS [Rho(D) Immune Globulin (Human)] (50 μg) is a lower dose of Rho(D) immune globulin that is used in certain clinical situations.

If the father or baby is not conclusively shown to be Rh-negative, RhoGAM should be given to a Rh-negative mother in the following clinical situations to prevent Rh immunization:

  • After delivery of an Rh-positive baby
  • Routine prevention of Rh immunization at 26 to 28 weeks of pregnancy
  • Maternal or fetal bleeding during pregnancy from certain conditions
  • Actual or threatened pregnancy loss at any stage. MICRhoGAM should be used in Rh-negative women who experience pregnancy loss at or up to 12 weeks of pregnancy
  • Ectopic pregnancy (pregnancy in which the fertilized egg implants outside the uterus)


RhoGAM or MICRhoGAM should NOT be used if you are Rh-positive or if you have had a severe allergic reaction to human immune globulin.

Be sure to tell your healthcare provider about all your medical conditions, including:

  • If you have ever had a severe allergic reaction or a severe response to human immune globulin.
  • If you have an immunoglobulin A (IgA) deficiency. RhoGAM and MICRhoGAM contain a small quantity of IgA and there is a potential risk of an allergic reaction in IgA-deficient individuals. Ask your healthcare provider if you are not sure.
  • Your recent history of vaccinations. Certain types of vaccines (ones containing a live virus) may not work as well for you if you are also receiving immune globulin products like RhoGAM or MICRhoGAM. The antibodies in RhoGAM and MICRhoGAM may prevent the vaccine from working. Before you get a vaccine, tell your healthcare provider that you have received RhoGAM or MICRhoGAM.

Allergic reactions to RhoGAM or MICRhoGAM may occur. You should be observed for at least 20 minutes after administration. Signs and symptoms of an allergic reaction include itchy rash (hives/urticaria), tightness of the chest, wheezing, low blood pressure and anaphylaxis (which may also include throat or tongue swelling, shortness of breath, vomiting, hives and/or lightheadedness).

RhoGAM and MICRhoGAM are prepared from human plasma and may contain infectious agents that can cause disease. Numerous tests have been applied in the plasma collection process and specific viral inactivation steps have been added to the manufacturing process to minimize the risk of transmission of diseases, but all risk cannot be eliminated.

The most common side effects of RhoGAM and MICRhoGAM are swelling, hardening, redness, and mild pain at the site of the injection. A small number of patients have noted a slight fever.

Your healthcare provider should provide you with a completed Patient Identification Card for you to retain and present to other healthcare providers.

You are encouraged to report adverse events of prescription drugs to the FDA. Visit or
call 1-800-FDA-1088.

Click here for the RhoGAM and MicRhoGAM Full Prescribing Information.
This site is intended for residents of the US only.

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