Hemolytic Disease of the Newborn (HDFN): Please Get the Rhogam Shot

Why Would I Need an Injection During Pregnancy and Postpartum?

Hemolytic disease of the fetus and newborn (HDFN), is a blood disorder that happens when the blood types of a mother and baby are incompatible. Prior to the introduction of RhoGAM®  in 1968, HDFN was a major cause of infant mortality, responsible for an average of 10,000 deaths annually in the United States (SOURCE). The RhoGAM® injection is to be given to all Rh negative pregnant women at 28 weeks to protect from sensitization for the remainder of the pregnancy, and then within 72 hours of delivery. A blood test will be done within a few hours post delivery, and will tell the provider the amount of fetal blood transferred to the mom’s bloodstream. This will determine the dosage of RhoGAM® needed to prevent sensitization.

When injected with RhoGAM®, antibodies circulate in the Rh-negative mother’s bloodstream and prevent her immune system from making the sensitized antibodies that would threaten a baby with Rh-positive blood (SOURCE).

Because of the widespread use of the RhoGAM® injection, these reactions due to negative/positive blood incompatibility are not very common.

However, there are certain circumstances where the injection could potentially be missed during a mom’s first pregnancy, thus putting future infants at risk. An example of this would be if a pregnant woman has had an early miscarriage/ abortion and does not know her blood type or even that she may need the  injection at all to protect future babies, or if a mom declines the RhoGAM® injection because she does not understand its importance.

My hope is that this post will help moms understand the importance of receiving this injection. 

What Can Happen to My Future Babies if I Do Not Receive RhoGAM® and Become Rh Sensitized? What is HDFN?

HDFN basically is when those antibodies cross over into a baby’s blood stream and attaches to the Rh + antigens, marking them to be destroyed. The rate at which this happens can be mild, moderate or severe. In mild cases the newborn infant may have mild anemia and jaundice requiring no medical treatment. However, in more severe cases an infant can suffer lasting health issues (brain damage, enlarged spleen, liver dysfunction, hydrops fetalis) or even death (SOURCE).

These babies may need phototherapy, or blood transfusions either before or after birth. Phototherapy is a UV light used to break down extra bilirubin in order to reduce jaundice. If left unmanaged, bilirubin toxicity can cause a host of problems for a newborn, including extreme drowsiness, poor feeding, irritability, seizures and developmental delays (see table below).

Effects of Bilirubin Toxicity in Newborns




Athetoid cerebral palsy

Poor feeding


High-frequency hearing loss

High-pitched cry


Paralysis of upward gaze



Dental dysplasia

Oculogyric crisis

Developmental delays



(Table cited from http://www.aafp.org/afp/2002/0215/p599.html)

A Bit More About Rh Incompatibility and Sensitization

Most infants in recent days do not get their blood type cross-matched at birth. While blood type information used to be a staple in baby books, it is often considered to be an unnecessary test to complete on newborns.  That is, unless we have an Rh negative mom.

When you have your first set of antenatal labs drawn (part of the reason why you need to have routine prenatal care), your doctor will find out your blood type. If your blood type (O, A, B, AB) has a negative behind it, then you are Rh negative. Rh incompatibility happens when you are Rh negative and your fetus is Rh positive.

While mothers and babies do not share the same blood system during pregnancy, there can be mixing of the blood through the placenta. This can at times happen during pregnancy, labour and/or birth. Once this mixing of blood occurs when there is a Rh incompatibility, antibodies against baby’s blood will be produced in mom’s blood system. The mom will then be considered “Rh sensitized”. This can be determined through a simple lab test (+ Coombs) and will not change in time. During each pregnancy, a mother’s antibodies are passed to her fetus through the placenta, to help the newborn infant’s chances of survival with its primitive immune system (SOURCE). While these antibodies are normally very helpful, Rh sensitization can put future fetuses that mom carries at risk of developing HDFN (SOURCE). Once it is found that a mom is Rh sensitized, her future pregnancies will be monitored very closely for signs of HDFN.

When Will I Need this RhoGAM® Injection if I am Pregnant and Rh Negative?

It is recommended that all women with Rh negative blood types be given the RhoGAM® injection within 72 hours of miscarriage, abortion, delivery, or after any abdominal injury or invasive test.

The Rh factor is present on red blood cells from the time the baby is of 8 weeks gestation. If a miscarriage or abortion occurs before 13 weeks, a mom should be given a smaller dose called MICRhoGAM, and if after should be given the full dose of RhoGAM® to prevent injury to future newborns. This injection needs to happen within 72 hours of miscarriage, abortion, delivery, abdominal injury or invasive test (SOURCE).

If you or someone you know has a negative blood type, make sure to not only let your doctor know right away when you are pregnant, but also make sure to remind them that you need this injection during pregnancy, as well as within 72 hours of miscarriage, abortion, delivery, abdominal injury or invasive test.

This information very well could protect an infant’s life. Please share with friends and family!


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Hi! I am a Registered Nurse on a unit that encompasses labour and delivery, postpartum, medical, surgical and palliative care in a rural hospital in Ontario, Canada. I am a mom of two and am passionate about women's rights, mom and infant care, parenting and nursing. I hope to create an educational, entertaining and highly relatable resource for women around the world. Thanks for stopping by! Xo, The Mama Nurse

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