Rh Immune Globulin (RhIg)

Rh Immune Globulin (RhIG) is a life-saving medication used to prevent Rh incompatibility between Rh-negative mothers and their Rh-positive babies. It works by preventing the mother’s immune system from producing harmful antibodies (Anti-D Antibodies) that could cause Hemolytic Disease of the Fetus and Newborn (HDFN). A person is Rh-negative if they have a negative blood type, like O-, A-, B-, or AB-. In most countries, women find out their blood type during their first trimester of pregnancy in order to determine if they need RhIg.

RhIg is also known by names such as RhoGAM®, Rhophylac®, WinRho®, HyperRHO®, and Anti-D.

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Quick Facts

What RhIg Does

RhIg helps prevent the body from making anti-D antibodies after exposure to Rh-positive blood.

What It Prevents

It helps reduce the risk of Rh sensitization, which can lead to hemolytic disease of the fetus and newborn (HDFN).

How It Is Given

RhIg is given as an injection. It is a preventative medication, not a vaccine.

Why Timing Matters

It is commonly given during pregnancy and again after delivery if the baby is Rh-positive.

How Does RhIg Work?

If an Rh-negative person is exposed to Rh-positive fetal blood during pregnancy or birth, the immune system may respond by making anti-D antibodies. Those antibodies can cross the placenta in a future pregnancy and attack a baby’s red blood cells. RhIg works by introducing a small amount of anti-D antibodies, tricking the immune system into thinking it has already produced its own antibodies. This prevents the formation of dangerous naturally occurring anti-D antibodies in response to Rh-positive blood. The injected antibodies temporarily circulate in the body before breaking down. RhIg does not cause alloimmunization or sensitization , and it is not a vaccine. It is a preventative medication given via an injection.

When Is RhIg Commonly Recommended?

RhIg may be given:

At around 28 weeks of pregnancy
Within 72 hours after delivery
After miscarriage or abortion
After abdominal trauma
After amniocentesis or CVS
In cases of vaginal bleeding during pregnancy

RhIg is generally not needed if:

You are Rh-positive
The fetus is confirmed Rh-negative
You are already alloimmunized with anti-D antibodies
The biological father is confirmed Rh-negative and paternity is certain

Safety, Effectiveness, and Side Effects

Effectiveness

RhIg has been shown to reduce the risk of Rh sensitization to just 0.1-0.2% when given at the recommended times points in pregnancy and after delivery.

Common Side Effects

Mild soreness at the injection site
Redness or swelling
Occasional mild fever

      Safety note: RhIg is made from screened human plasma. Manufacturing includes multiple safety steps and viral reduction procedures.
    

RhIg Brand Names and Package Inserts

Rh Immune globulin may be given under different brand names. You can view the official package inserts for each product below.

RhoGAM® WinRho® Rhophylac® HyperRHO®

History of RhIg

Before RhIg became available, Rh disease caused widespread fetal and neonatal death and serious long-term complications. The discovery of RhIg in the 1960s transformed maternal-fetal care and remains one of the most important advances in preventing severe HDFN.

Key contributors to the development of anti-D programs included Dr. Vincent Freda, Dr. John Gorman, and James Harrison, whose rare plasma donations played an important role in Australia’s anti-D program.

The postpartum administration of Rh D immune globulin reduced the rate of Anti- D alloimmunization in at-risk pregnancies from approximately 13–16% to approximately 0.5–1.8%. The risk was further reduced to 0.14–0.2% with the addition of routine antepartum administration.

How RhIg Is Made

RhIg is made from human plasma collected from donors who have anti-D antibodies. These donors are carefully screened, and plasma is processed using multiple safety steps before being made into medication.

Learn more about how to support specialty anti-D donor programs in the “How You Can Help” section below.

RhIg After First Trimester Pregnancy Loss

Recommendations differ among medical organizations about whether RhIg is needed after losses under 12 weeks. Some groups support selective use, while others support broader administration when feasible.

At the Allo Hope Foundation, we support patient education and individualized counseling. We also recognize the concern that even rare sensitization events can have devastating consequences in future pregnancies.

Recent studies show a very low risk of Rh sensitization after first trimester losses, but the true threshold for fetal-maternal hemorrhage remains unclear. At Allo Hope Foundation, we are in agreement with SMFM and advocate for RhIg to be given in first trimester pregnancy losses.

What If I Feel Uncomfortable Receiving RhIg?

Medical decisions during pregnancy can feel deeply personal and overwhelming. It is normal to want clear information before making a decision.

At the Allo Hope Foundation, our goal is not to pressure patients, but to provide accurate information, support informed decision-making, and help families understand the risks, benefits, and alternatives.

RhIg is not a vaccine and does not cause sensitization. It is a preventative medication designed to reduce the risk of anti-D antibody formation.

What Are My Options If I Do Not Want to Receive RhIg?

Options to discuss with your provider

Cell-free fetal DNA (cffDNA) testing for fetal RhD status
Confirmed paternal Rh status if paternity is certain
Shared decision-making based on your pregnancy history and risk

cffDNA testing

There is approximately a 40% chance that if you are Rh negative, your baby will also be Rh negative, in which case RhIg would not be necessary. The cffDNA test offers a reliable, non-invasive way to confirm your baby’s blood type to help guide your decision about whether to proceed with RhIg.

In some countries, fetal RhD testing is already used to guide RhIg administration and conserve doses.

What Can Happen If RhIg Is Refused and the Baby Is Rh-Positive?

      Important: Patients always have the right to make informed decisions about their care. At the same time, it is important to understand that refusing RhIg can increase the risk of sensitization and serious complications in future pregnancies.
    

Sensitization: There is a 13-16% chance that without RhIg, a mother can develope permanent Anti-D antibodies.
Future pregnancy risk: A Rh-positive pregnancy can become high risk and lead to Hemolytic Disease of the Fetus and Newborn (HDFN).
Potential complications: HDFN can cause severe fetal anemia, hydrops, preterm birth, NICU admission, and fetal or neonatal death.
Complex treatment: Management may involve intensive monitoring and intrauterine transfusions.

If RhIg Is Declined: Follow-Up Testing Matters

If a patient declines Rh immune globulin (RhIg), follow-up testing after pregnancy is an important step in understanding future risk.

Consider antibody screening 3-6 months after pregnancy to determine whether anti-D antibodies have developed.

This information is critical for preconception counseling and planning, as sensitization (if it has occurred) is permanent and can impact future pregnancies.

Knowing your antibody status allows your care team to guide appropriate monitoring and management early in any subsequent pregnancy.

Global Shortage of RhIg

RhIg is still not accessible to all women worldwide. In many regions, it is unavailable, unaffordable, or difficult to obtain in time. That lack of access contributes to preventable cases of HDFN and avoidable pregnancy loss, disability, and infant death.

Expanding access to RhIg, increasing specialty donor programs, and using fetal RhD testing strategically are all part of improving global outcomes.

How Can You Help

The global shortage of RhIg highlights the urgent need for both increased access to prevention and stronger specialty plasma donor programs.

You can make a meaningful impact by helping expand access to RhIg for families around the world or by becoming a specialty plasma donor—both of which help prevent HDFN and save lives.

Donate to Help Provide RhIg in Kenya

Become a Specialty Plasma Donor →

Rh Immune Globulin (RhIG)