Canadian Blood Services’ Rare Blood Program represented at international congress

Dr. Nicole Relke is a transfusion medicine physician trainee at the University of Toronto and Canadian Blood Services and recipient of Canadian Blood Services Elianna Saidenberg Transfusion Medicine Traineeship Award (ESTMTA). Funded through philanthropic contributions from Canadian Blood Services’ financial donors, the ESTMTA makes it possible for a select number of Canada’s emerging medical leaders to access specialty transfusion medicine training.

Recently, Dr. Relke also received a Harold Gunson Fellowship to attend the 36th Regional Congress of the International Society of Blood Transfusion (ISBT) in Perth, Australia in October 2025. The Harold Gunson Fellowship supports young professionals in transfusion medicine who submit high-quality abstracts, providing travel grants so they can share their research on the international stage. Dr. Relke presented her work on the Canadian Blood Services Rare Blood Program and the management of patients with rare blood during pregnancy. Learn more about Dr. Relke’s experience at the conference as she describes it below.

What does receiving the Harold Gunson Fellowship mean to you? What learning or experience have you gained from participating?

It was an honor to have my research accepted as an oral presentation at ISBT Perth and to be awarded the Harold Gunson Fellowship, named after the late Dr. Gunson – a true leader in transfusion medicine.

This was my first ISBT Congress and it was an incredible experience. I attended the ISBT Young Professionals Breakfast where I met colleagues from all over the world and later connected with international experts in rare blood following my presentation. Those conversations opened new doors for collaboration and gave me ideas on how to stay engaged with ISBT as a young professional. I left the congress feeling inspired and excited by career and research opportunities gained from this experience, made possible through the support of the Harold Gunson Fellowship.

How is “rare blood” defined and who needs it?

Rare blood is defined as being negative for a high prevalence antigen with a frequency of less than 1 in 1,000 individuals or having a unique combination of antigens that are rarely found together. Some examples include Bombay, Jk null, or U negative blood types.

When exposed to foreign red cells through transfusion or pregnancy, antibodies may form against red cell antigens that the patient lacks on their own red cells. For example, if someone’s red blood cells are missing the high-prevalence U antigen, they can form an anti-U antibody. This means they will require U negative blood if transfusion becomes necessary, and finding U negative red cells can be challenging. Hospitals are unlikely to routinely have U negative red cells in their blood bank.

Pregnancy adds another layer of complexity! If a pregnant individual’s red cells lack an antigen that the fetus inherits from the father, they can develop an antibody that may cross the placenta. This may lead to hemolytic disease of the fetus and newborn, depending on the antibody specificity and titer.

Red cell transfusion after delivery is generally uncommon (reported as 0.7 per cent after vaginal delivery and 2.3 per cent after cesarian section according to a study of data published in the peer-reviewed journal, Transfusion). However, when a patient has rare blood, the clinical team may request rare red cell units be “on hand” (i.e. stored in the hospital blood bank) in case of unexpected bleeding or neonatal transfusion. How often these rare units are needed is unknown.

Tell us more about the research you presented at the conference and what it means to blood recipients.

Our study reviewed perinatal cases managed by the Canadian Blood Services Rare Blood Program between January 1, 2023 to December 31, 2024, to better understand how rare blood is used during pregnancy. We found 189 rare blood cases for 161 unique patients. 39 (24.2 per cent) of the 161 cases were prenatal and three were related neonates (babies less than four weeks old). The most common antibody was anti-U, followed by anti-Jra and anti-Lub.

In most cases, hospitals requested rare blood on hand at the time of delivery, typically 1 unit. Only two pregnant individuals (5.1 per cent) required transfusion at delivery, and three pregnancies (7.7 per cent) required intrauterine transfusion (IUT) support before birth. Two of these three pregnancies survived to delivery, and both neonates required postnatal transfusion.

A total of 52 rare units were acquired to support 26 pregnancies over the study period, half frozen and half freshly donated. Most units (73 per cent) were not transfused; many of these liquid units were frozen and returned to the rare blood inventory for future use.

The program was able to fulfill 100 per cent of rare blood orders, thanks to collaboration with our international partners. About 27 per cent of units were imported – from Hema-Quebec, the American Rare Donor Program, and the Japanese Red Cross. Reassuringly, the cases that required transfusion were typically predictable: both neonates that received IUTs required postnatal transfusions, and one of two women who required transfusion at delivery was known to be at high risk of postpartum bleeding.

“Our research highlights that the provision of rare blood in pregnancy relies on a truly collaborative effort between the hospital, Canadian Blood Services Rare Blood Program, international rare blood programs, and dedicated rare donors.”

Dr. Nicole Relke, Canadian Blood Services transfusion medicine physician trainee

What are the key takeaways of your presentation?

• For health care professionals: The most important takeaway is plan ahead! Successful management of rare blood in pregnancy requires coordination between the clinical team, transfusion service, and blood supplier. Fresh (liquid) units are preferred for delivery because they have a longer shelf life and, if not transfused, can be frozen then added to the rare inventory. Recruiting rare donors for liquid units and, when necessary, importing units from international partners when blood cannot be sourced in Canada, takes time. Early planning is critical!
  
  It is also essential to optimize maternal iron status before delivery. Identifying and treating iron deficiency anemia is one pillar of patient blood management that should be applied to all pregnant patients, especially those with rare blood types. Hematology consultation is often recommended at the hospital.

• For researchers: Our study highlights the importance of international collaboration in providing rare blood to patients. Achieving 100% order fulfillment was only possible through these global partnerships. It is important that we continue to work together to ensure the availability of rare blood for patients. The ISBT International Rare Donor Panel plays an important role in making this collaboration possible.
• For patients: Even if you never meet us, the Canadian Blood Services Rare Blood team is working behind the scenes to keep you and your baby safe, and to make sure blood is available whenever and wherever it is needed. Six months after delivery, you may be eligible to donate your own rare blood to help others. Since siblings are more likely to share your rare blood type, we often invite them for testing, too! Visit blood.ca for details and frequently asked questions about rare blood.

A heartfelt thank you to the ISBT Harold Gunson Fellowship, Canadian Blood Services medical officers Dr. Matthew Yan and Dr. Melanie Bodnar, and Canadian Blood Services program management associate Susan Shank for their mentorship on this project. And of course, thank you to all our amazing rare blood donors: you are truly one in a million (or at least one in a thousand!)

To learn more about how Canadian Blood Services financial supporters, through their contributions to the Elianna Saidenberg Transfusion Medicine Traineeship Award, make it possible for emerging medical leaders like Dr. Relke to access specialty transfusion medicine training and strengthen Canada’s community of transfusion medicine experts, visit blood.ca: Make a lifesaving gift - Canadian Blood Services

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The opinions reflected in this post are those of the author and do not necessarily reflect the opinions of Canadian Blood Services nor do they reflect the views of Health Canada or any other funding agency.