What Happens When You Get a RhoGAM Shot

Some pregnant people need to get RhoGAM shots during pregnancy. This treatment is used to prevent a potentially serious complication that can occur if the pregnant person has a negative blood type and the baby has a positive blood type. So, depending on what blood type you and your baby are, you may need to get one or more RhoGAM shots during your pregnancy. Keep reading to learn more about RhoGAM shots, what they do, and what to expect if you need one.

What Is Rh Factor?

Rh factor is an inherited component of a person's blood type. Rh, or rhesus, is a protein that rides along on the surface of the red blood cells of about 85% of people. If the protein is found on your red blood cells, you are Rh-positive. If it's not there, you're Rh-negative.

Early in your pregnancy, you'll take a blood test to determine if your blood is Rh-positive or Rh-negative. If you are Rh-negative, then your body may develop an immune response to the Rh in your baby's blood if they are Rh-positive. This is called Rh incompatibility.

What Is the RhoGAM Shot?

The RhoGAM shot is an injection made up of antibodies called immunoglobulin that stop an Rh-negative person's immune system from creating antibodies to Rh-positive blood. The shot effectively protects the red blood cells of a future Rh-positive fetus from being attacked by the Rh-negative gestational parent's antibodies.

According to the product website, "RhoGAM prevents the Rh-negative mother from making antibodies during her pregnancy. As long as the Rh-negative mother receives RhoGAM appropriately during every pregnancy, her babies are at very low risk of developing [anemia]." The shot also prevents other complications, such as jaundice, swelling, or brain damage, that can occur due to untreated Rh incompatibility.

Sheila Chhutani, MD, an OB-GYN practicing at Gynecological and Obstetrical Associates in Dallas, explains that RhoGAM is an immunoglobulin, or manufactured antibodies, that will attach to the rhesus protein in the gestational parent's blood, not allowing their body to process or "see" that protein to start manufacturing its own antibodies. "The RhoGam does not cross the placenta and will not harm the baby," she adds.

Why Do Some Pregnant People Need a RhoGAM Shot?

During pregnancy and childbirth, there is a risk of the parent and fetus's blood coming into contact. If this happens when the pregnant person is Rh-negative and the fetus is Rh-positive, the gestational parent's immune system may produce antibodies that could attack the baby-to-be's Rh-positive red blood cells.

Think of antibodies as little warrior cells that go off to do battle against invading forces. Any time you are exposed to an antigen, your body produces antibodies specific to that antigen, so if it is exposed again, your immune system is ready to fight it off more efficiently. It can take several months for immunity to develop.

However, due to this time lag, your Rh factor isn't typically an issue during first pregnancies. It isn't until subsequent pregnancies when antibodies to Rh are already present that Rh incompatibility can cause problems.

Since you and your baby don't share a circulatory system, there are only a few circumstances during pregnancy when fetal blood can come into contact with maternal blood. The most common ways for cross-contamination of fetal blood with the blood of the pregnant person to occur are during the following:

• Abdominal injury
• Abortion
• Amniocentesis
• Chorionic villus sampling (CVS)
• Ectopic pregnancy
• Labor and delivery
• Miscarriage or stillbirth
• Molar pregnancy
• Vaginal bleeding

If the Rh-negative parent gets sensitized to Rh, the antibodies they develop can cross the placenta and attack an Rh-positive fetus's red blood cells. This can cause a variety of complications for the baby, including the following:

• Anemia
• Brain damage
• Hearing or movement problems
• Heart failure
• Swelling in the baby's tissues and organs
• Jaundice
• Mental Impairment
• Miscarriage
• Seizures
• Stillbirth

Taking a RhoGAM shot during the first and any subsequent pregnancies with Rh incompatibility prevents these potential complications.

When Is the RhoGAM Shot Given?

Typically, the RhoGAM shot is given at 28 weeks gestation, says Dr. Chhutan. It lasts for about 12 weeks, protecting you until the end of the pregnancy. Since a fetus's blood type is unknown during pregnancy, all Rh-negative pregnant people get the shot. "At delivery, if the newborn is Rh-positive, the [gestational parent] will receive another dose of RhoGAM," adds Dr. Chhutani. If the baby is Rh-negative, there is no need for an additional shot.

This last injection is given just in case there was any cross-contamination of blood from an Rh-positive baby to the birth parent during delivery. This additional dose of immunoglobulin will prevent the gestational parent's body from producing antibodies that may place future pregnancies at risk. RhoGAM injections are also given to Rh-negative people within 72 hours of experiencing a miscarriage or stillbirth.

RhoGAM Shot Side Effects

Side effects from the RhoGAM shot are usually mild and don't harm the baby or affect breastfeeding. Common side effects of the shot include the following:

• Pain at the injection site
• Swelling, itching, and/or redness at the injection site
• Mild fever

Less common side effects can include:

• Allergic reaction
• Headache
• Joint or muscle pain
• Fatigue.

If you don't feel well or experience any of these symptoms after getting your injection, contact your doctor.

Is the RhoGAM Shot Safe?

For the vast majority of pregnant people, RhoGAM is very safe and effective. In fact, research shows that the rate of developing Rh sensitivity goes down to almost zero (less than 1%) when RhoGAM injections are given.

On the other hand, not getting the shot puts a baby at significant risk. In fact, it's estimated that 50,000 fetal deaths occur annually worldwide due to untreated Rh incompatibility. Significant side effects in the baby or pregnant person are rare. Additionally, note that it is safe to get a RhoGAM shot even if it turns out that your baby is also Rh-negative.

While the RhoGAM shot is given to most Rh-negative pregnant people, it is not recommended for everyone. Some people should not get the RhoGAM shot due to issues that make it unsafe. These contraindications include if you:

• Already have Rh-positive antibodies
• Have an allergy to immunoglobulin
• Have hemolytic anemia
• Have recently gotten another vaccine (RhoGAM may reduce its effectiveness)

In these cases, the pregnancy will be monitored for any signs of complications due to Rh incompatibility.