Just Diagnosed

Diagnosed with Antibodies in Pregnancy?

You Are in the Right Place

Start Here

If you’ve been told you have antibodies or a positive antibody screen, you are in the right place! With proper care and the right doctor, most families have safe alloimmunized pregnancies and healthy babies.

Find Support from Other Moms →

Patient-led. Medically informed. Trusted by families and clinicians worldwide.

Pregnant woman

Understanding Your Diagnosis

Maternal Alloimmunization and HDFN

A brief overview for newly diagnosed patients and their families.

What is red blood cell alloimmunization and how does it cause HDFN?

Maternal alloimmunization occurs when a woman makes red blood cell antibodies as a result of foreign blood mixing. These antibodies can cross the placenta and attack the unborn child, a disease called hemolytic disease of the fetus and newborn (HDFN). HDFN can have devastating consequences including anemia, hyperbilirubinemia, and death. With close monitoring and timely treatment, babies with HDFN have a very high survival rate. Unfortunately, due to the rarity of alloimmunization and the variation in care practices around the world, well-managed pregnancies and ideal infant outcomes are not universal – but they can be!

What causes maternal alloimmunization?

Most women find out that they have a red cell antibody, or maternal alloimmunization, when their first trimester antibody screen comes back positive. This often comes as a shock since the antibodies (such as anti-D, anti-K, anti-E, anti-c, anti-Jka and others), weren’t present/detected in the previous pregnancy. Our immune system creates antibodies when something foreign is detected in our bodies. The antibodies keep us safe by attacking the foreign thing (such as a virus) that is threatening us. This can happen when we are exposed to a blood type that is different from our own. Our body thinks the foreign blood is a threat, so our immune system creates antibodies specifically designed to destroy the different blood type. This exposure happens during pregnancy, childbirth or from a blood transfusion.

What are the risks?

Once your body has created antibodies you will have them for the rest of your life. They will not affect you or put you in danger unless you need a blood transfusion. The donor blood you are given must be matched to your specific antibodies or you could be at risk for a hemolytic transfusion reaction. It is important to tell your doctors about your antibodies for the rest of your life, and especially before a blood transfusion.

The biggest risk is to your baby during pregnancy and after birth. Your antibodies can cross the placenta during pregnancy and destroy your baby’s red blood cells, causing the baby to become anemic. If fetal anemia is not treated properly during pregnancy, serious problems such as hydrops, organ damage, or death can occur. If HDFN is not treated properly after birth, serious problems such as anemia, high bilirubin, brain damage, or death can occur. Infants with HDFN are also at risk for neutropenia and thrombocytopenia.

Thankfully there are treatments that can be used to protect your baby from these risks.

Family photograph
Family photograph
Family photograph
Mother smiling at her newborn baby

What to Expect

Monitoring and Treatment

During Pregnancy

Before Birth

An exact monitoring and treatment plan will vary, but in general women can expect:

  • Blood work (titers or quants) every 4 weeks until 24 weeks, then every 2 weeks until delivery.
  • Weekly MCA Doppler Ultrasounds if the blood work comes back at or above a specific threshold (1:16 for most antibodies, 1:4 for anti-K).
  • If the MCA Dopplers show signs of anemia, an intrauterine blood transfusion will be given.
  • Weekly non-stress tests and biophysical profiles from 32 weeks until delivery.
  • Delivery between 37 and 38 weeks. If there are signs of fetal anemia or if IUTs were needed, delivery may be earlier.
Explore Prenatal Resources →

Newborn Care

After Birth

An exact monitoring and treatment plan will vary, but in general women can expect:

  • Blood work at birth to check for the baby’s blood type, anemia, bilirubin, neutropenia, & thrombocytopenia.
  • Blood work for bilirubin every 6-24 hours while in the hospital.
  • Follow up labs every 1-2 days for the first couple of weeks to check on baby’s bilirubin and hemoglobin levels.
  • Weekly hemoglobin checks until 6-12 weeks of age depending on clinical severity.
  • Babies who were not anemic in the hospital can become anemic later.
  • Medical literature says babies with HDFN should not be given iron supplement without a ferritin test
Explore Neonatal Resources →

Explore the Resource Library

Browse Allo Hope Foundation's complete collection of educational materials.

Visit the Full Resource Hub →

Planning for the Future

Can I Have More Children?

Absolutely! You will always have antibodies, even when you are not pregnant or when your titer is very low, but your antibodies do not have to limit your family size. It has been thought that subsequent pregnancies are affected at earlier gestations, and more severely, however that is not always the case. With improvement in care practices, and new treatment options, there are several choices available if you wish to have more children.

While there are many ways to grow your family, there are also alternatives to natural conception that avoid the risk of HDFN altogether. If you want to learn more about how to prepare for another alloimmunized pregnancy, talk to your doctor before you get pregnant again. Alloimmunization does not have to limit your family size. You have options.

Family-building resource photograph

Family-Building Options

Learn about alternative paths to growing your family, including reproductive options that may help reduce or avoid the risk of HDFN in a future pregnancy.

Explore →
The Allo Podcast cover art

Podcast Resources for Newly Diagnosed Families

A new diagnosis of alloimmunization or HDFN can bring a lot of questions and unfamiliar medical terminology. The Allo Hope Podcast offers approachable conversations to help you understand your diagnosis, learn about prenatal testing and monitoring, find experienced medical care, and prepare for what comes next. These episodes can also be a helpful resource to share with family and friends who want to better understand what you're navigating.

Back to Top
Translate »