HDFN is rare - be aware - ask for specialist care
Did you know that rare diseases can also occur during pregnancy? These diseases can have an impact on the development of the baby (foetus) while the mother is pregnant.
One such condition, Haemolytic disease of the foetus and newborn (HDFN) occurs when the mother’s red blood cells are not compatible with the foetal red blood cells. It is not unusual for the mother and foetus to have different blood types. In rare cases where they are not compatible, the mother’s immune system sees the baby’s red blood cells as foreign and produces antibodies to fight these in a process called maternal alloimmunisation. This causes the baby’s red blood cells to break down quickly and leads to foetal anaemia.
Foetal anaemia can increase the risk of preterm birth and lead to other complications; such as excess fluid in the organs and jaundice when the child is born.
Additionally, the mother’s immune system will store antibodies to fight babies’ red blood cells in future pregnancies. This is called sensitisation and foetal anaemia can be more severe in future pregnancies than in the first affected pregnancy.
HDFN can be managed if it is diagnosed early on in pregnancy. If a pregnant woman is at risk of HDFN, then she should be referred to a specialist team of physicians. It is important that women at risk of HDFN are aware of this and seek referral to specialist care – this is the first step towards improving outcomes for mothers and babies affected by this rare disease.
HDFN is a rare pregnancy condition which occurs when the mother’s red blood cells are not compatible with the red blood cells of her unborn baby (the foetus). In cases where they are not compatible, the mother’s immune system sees the baby’s red blood cells as foreign and produces antibodies to fight these, which, in rare cases can cause foetal anaemia. Foetal anaemia is when the amount of circulating red blood cells and haemoglobin in a foetus fall below normal levels. Because red blood cells transfer haemoglobin and oxygen through the blood to the tissues who need it, foetal anaemia can have several adverse effects, including heart complications.
A risk of HDFN should be picked up during routine screening with a blood test. There are many different blood group systems. The ABO and Rhesus (Rh) systems are the most well-known and incompatibilities within these, as well as others, can lead to HDFN.
All women should have their blood group and antibody status determined at the beginning of their pregnancy.
If the mother’s blood group and antibody status indicate a risk of incompatibility with the baby’s, non-invasive foetal genotyping using maternal blood is carried out to confirm this. Paternal testing can be also completed to help identify the level of incompatibility. These tests will also enable identification of the type and extent of incompatibility and guide the course of care for the mother and baby.
Antibody levels should also be monitored throughout the pregnancy. If it is confirmed that the mother is producing antibodies against the baby’s red blood cells, a regular antibody titre test should be undertaken to determine the level of antibodies within her blood and thus, the level of risk to the baby.
With subsequent exposures between the foetus’ and mother’s blood, the levels of antibodies and thus the risk to the foetus may further increase, a process called sensitisation.
If sensitisation occurs, the next time the woman is pregnant, her body produces antibodies immediately.
Early engagement with a specialist physician who has knowledge and expertise in HDFN is essential to ensure that the pregnancy is diagnosed accurately, assessed for potential risk and closely monitored throughout this and subsequent pregnancy.
Haemolytic disease of the foetus and newborn (HDFN) is a rare pregnancy condition which occurs when the mother’s red blood cells are not compatible with the foetal red blood cells and this can lead to foetal anaemia.
There is a range of severity associated with HDFN ranging from mild to very severe. In the most severe cases, foetal death from heart failure may occur.
If there is an incompatibility between the mother and her baby’s red blood cells, the first pregnancy tends to be unaffected as the mother has not yet been exposed to her baby’s blood. Women may not even be aware of the incompatibility with their newborn!
However, upon exposure to their baby’s blood e.g. during childbirth, mother’s and baby’s blood can mix. In the case of incompatibility, this may cause the mother to start producing antibodies against the baby’s red blood cells which can be dangerous in subsequent pregnancies. Therefore, it is really important that women are educated on the risk of HDFN starting already from the first pregnancy. For women with RhD incompatibility, preventive therapy can be administered which prevents the mother’s immune system from attacking the foetus.
Additional factors which can affect the severity of the disease include:
- The type of antibody that a mother produces – some types of antibodies carry higher risk than others and some can be treated with a preventive therapy
- Antibody titres – the level of antibodies in the blood should be measured regularly throughout pregnancy as in some cases, higher levels are linked to increased severity and risk of foetal anaemia (too low number of red blood cells)
- The number of previous pregnancies affected by HDFN – the severity of HDFN tends to be higher with each subsequent pregnancy
There are many steps that your specialist physicians and their teams can implement to monitor the disease and manage any potential associated risks. Antibody levels should be monitored throughout the pregnancy. Regular ultrasounds of the middle cerebral artery (MCA) Doppler should also be undertaken by a specialist physician to monitor the baby’s blood flow and detect any presence of foetal anaemia.
HDFN should be managed by a team of HDFN specialists to ensure continuous monitoring of the mother and baby to determine the risk to the foetus and enable early intervention if needed.
| haemolytic | referring to destruction of blood cells |
| foetus | unborn baby |
| foetal | referring to the unborn baby |
| compatible | matching to each other |
| antibody
|
component of the immune system that identifies and attacks objects recognised as foreign/non-self in the human body |
| blood type
|
also known as blood group: differences in structures on the surface of human red blood cells |
| maternal alloimmunisation
|
process when a pregnant women’s immune system produces antibodies against the red blood cells of her unborn baby (alloantibodies) |
| anaemia | too low number of red blood cells or haemoglobin resulting in reduced oxygen-carrying capacity in the blood |
| premature birth | birth of a baby before the completion of 37 weeks of gestation |
| jaundice
|
due to the build-up of a yellow pigment in the body (as consequence of destruction of red blood cells) skin and eyes appear yellowish |
| sensitisation
|
process of becoming reactive to substance (in the case of HDFN the mother’s immune system becomes reactive to the blood type of her unborn baby) |
| haemoglobin
|
protein in red blood cells that helps to transport oxygen and carbon dioxide within the human body |
| non-invasive
|
procedure that does not require injuring the skin or entering the body |
| genotyping
|
analysing a person’s DNA/genetic variation. This information can help determine an individual’s predisposition to certain diseases through a simple blood test |
| paternal | regarding the father |
| incompatibility | inability of two substances or entities to coexist or function together harmoniously |
| antibody titre | level of antibody in the blood |
| exposure | coming into contact |
| RhD | refers to the presence or absence of a specific structure (a protein called “D antigen”) on the surface of red blood cells |
| preventive | measures taken to avoid that a disease or condition occurs or worsens |
| administered | given or applied |
| severity | seriousness or intensity of a medical condition or symptom |
| ultrasound | a diagnostic imaging technique that uses high-frequency sound waves to create images of internal organs, tissues or unborn babies |
| middle cerebral artery | an artery in the brain |
| Doppler | A technique used in medical imaging that uses sound waves to measure blood flow |
Awareness is key: HDFN statement
We asked Bethany Weathersby, founder and executive director of the Allo Hope Foundation, what HDFN means for affected families and why raising awareness of this rare disease is so important. She shares an important and hopeful message for parents: with early detection, close monitoring, and specialist care, HDFN can be managed — and babies can go on to live healthy lives. That’s why awareness is vital.
Watch her statement to learn how parents can play a key role in ensuring the best possible care for their baby:
Expert insight: HDFN interview
What does specialist care for HDFN involve? What monitoring is needed during pregnancy and after birth? And what does the long-term prognosis look like for affected babies?
In our interview, Professor Stefan Verlohren, Director of the Department of Obstetrics and Fetal Medicine at the UKE (University Medical Center Hamburg-Eppendorf), provides expert answers to these key questions and more.
Watch four short statements in our HDFN playlist or view the full interview:
Personal insight: HDFN journeys
Erika’s story
Erika from Canada shares her feelings and experiences following her diagnosis and how it has shaped her journey. Today, she is an advocate for better education about HDFN for healthcare providers.
“My first thought when I received the diagnosis was: Will my baby survive all of this? I had little information initially of what HDFN was aside from being told it was incredibly rare and would cause anaemia requiring transfusions. It was confusing to understand.”
HDFN is a rare disease, affecting only 2.5 per 100,000 births in high-income countries, which means that primary healthcare providers often may not have detailed information about the condition because they have seen so few patients with it.
“What helped was doing my own research on the diagnosis and finding resourceful groups like the Allo Hope Foundation, but more education needs to be provided to healthcare providers.”
Thank you, Erika, for speaking out! Your story highlights the need for better support and education for both patients and healthcare professionals.
Stephanie’s story
Stephanie from Germany shares her journey with HDFN and how, despite the challenges, she has found peace and hope.
As is typical of HDFN, Stephanie’s alloantibodies were first discovered during her second pregnancy:
“I was diagnosed after my first birth, in the beginning of my second pregnancy. I was afraid and feeling helpless and felt especially uninformed about the risk and possible treatments.”
Finding specialist care: a difficult journey
After her antibodies were detected, Stephanie knew she needed specialist care, but finding it wasn’t easy:
“I did seek specialist care after my diagnosis. But my local gynaecologist was not able to help so much. I had to do a lot of research myself in order to find a specialist in this field. It was quite difficult to find, and it was a four hour drive away.”
Early delivery: from fear to peace
Stephanie feared the consequences of a preterm birth for her baby, but fortunately, her NICU journey had a happy ending:
“Yes, I feared early delivery. My first sensitised baby was not delivered early. My second was born at 36+2, induced at 36+0. It was very hard in the beginning and during NICU time, but today, three months later, I am at peace with how it went and compared to other very serious illnesses and conditions, it was really not that bad.”
The decision to have another baby
Stephanie and her partner were initially concerned about having more children after the diagnosis. After taking the time to learn more and reflect, they decided to take their chances:
“Yes I wanted to have more babies. After the diagnosis we waited a year to make up our minds, inform ourselves etc. to make a decision. Still, we had some concerns but we took the risk and are so glad we did.”
Thank you, Stephanie, for sharing your story full of hope and peace! Your experience helps others to understand the challenges of HDFN and the importance of seeking specialist care.
Namrata’s story
Namrata from Australia shares her journey with HDFN, reflecting on her challenges and the importance of raising awareness for others facing similar experiences.
Namrata’s alloantibodies were not detected during her first pregnancy, and it wasn’t until her fourth pregnancy that she was fully informed about the severity of HDFN:
“My first pregnancy ended as a stillbirth at 21 weeks. My antibodies were detected during my second pregnancy, which also ended as a stillbirth at 15 weeks. I did not have enough information about HDFN at that time. I only knew in detail about HDFN once I was pregnant with Aavya, my fourth pregnancy. I did not know about the severity of this disease before this. I knew about it at 17 weeks pregnant when my daughter was already severely anaemic. I think most of the healthcare professionals are not fully aware about this. My General Practitioner and obstetrician never explained about this. They only said I had Kell antibodies, but they did not explain how severe anaemia in the foetus can develop with these antibodies. There is a big gap in information about this disease. It is crucial to spread information about HDFN so that new mums who have antibodies can get the information and support they need.”
Facing the diagnosis: fear and hope
When Namrata was diagnosed during her fourth pregnancy, she was overwhelmed:
“I thought I would lose her. I felt there was no light at the end of the tunnel. My doctor was very nice and explained the treatment options for anaemia really well, but he also made it clear that the risk of complications associated with IPT* and IUT** is high during early pregnancy, so I kind of lost hope and prepared myself for the worst outcome.
During that time, Allo Hope Foundation gave me hope. I had to listen to the podcast multiple times throughout the night. Also, I read Facebook posts about mums sharing their stories. I cannot thank Allo Hope Foundation and its members enough for giving me strength during the most difficult time of my life.”
Specialist care made all the difference
Having experienced specialists looking after her was crucial, says Namrata:
“I got lucky to find the best specialist. I actually went for my routine ultrasounds to the same clinic where one of my specialists works. I had two specialists involved in my care, one of the best and most experienced in IUTs for Australia. They looked after me really well. I am so grateful to them.”
Namrata’s story illustrates the importance of timely referral to specialist care so that women get the information and care they need.
The NICU journey: a time of fear and anxiety
Like many mothers, Namrata feared preterm birth and its consequences – and when it really happened, the fear continued:
“Yes, I did fear early delivery. Every time I went for an intrauterine transfusion, I got heightened anxiety associated with possible complications of transfusion, which could lead to preterm delivery. During my IUT at 31 weeks 5 days, my baby had bradycardia and she had to be delivered. I knew about the possible complications associated with IUTs, however, I was in shock at that time. I was still thinking my baby girl was still in my tummy for 2-3 days when she was already out and in the NICU. I was so worried and anxious the entire time she was in hospital. I used to get so scared to answer calls from the hospital because I was worried there might be something wrong with my baby. I am still a very anxious mum, even a small thing scares me. I have fear of losing her. I hope it gets better with time.”
Looking ahead: two hearts in one chest
Because of her experience, Namrata is not sure if she wants to have another baby:
“I still haven’t decided if I want to have another child. I feared having another preterm baby and having to spend a long time in hospital. I don’t have the strength to cope with the possible complications of IUTs.”
Thank you, Namrata, for sharing your story! By speaking out, you are helping others to understand HDFN and recognise the importance of awareness, support, and specialist care.
*IPT = Intrauterine peritoneal transfusion:
This is a medical procedure in which antigen-negative red blood cells are injected into the baby’s abdomen (peritoneal cavity). It is often used to treat babies who become anaemic at very early in pregnancy, when the umbilical vein is smaller and harder to access.
**IUT = Intrauterine transfusion:
This is a life-saving procedure where a needle is inserted through the abdomen and uterus into the baby’s umbilical cord or abdomen to give antigen-negative blood. This can help treat severe anaemia while the baby is still in the womb.
Further reading
For patients
For medical professionals
Transparency
The HDFN awareness campaign was independently developed and is powered by EFCNI in cooperation with The Allo Hope Foundation. We would like to thank Johnson&Johnson for their support of the topic HDFN.
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