A baby in the United Kingdom became one of the youngest known recipients of an intrauterine blood transfusion (IUT), after doctors performed the procedure at 16 weeks of gestation. The intervention took place at St George’s Hospital, London, in 2024, after clinicians identified signs of severe fetal anemia during routine antenatal monitoring.
The family of the baby who underwent a life-saving blood transfusion before birth expressed gratitude to the donors whose specially matched blood enabled the rare procedure.
According to a press release issued on April 21 by the NHS Blood and Transplant, Maisie Ransom was 16 weeks pregnant with Arthur when he contracted Parvovirus B19 infection, which resulted in severe fetal anemia.
According to NHS Blood and Transplant, Arthur developed fluid accumulation followed by heart failure in utero, prompting doctors at St George’s Hospital to carry out a rare intrauterine transfusion (IUT).
Intrauterine transfusion (IUT) is an invasive yet essential procedure used to treat severe fetal anemia, with evidence showing improved clinical outcomes.1
It involves processing carefully matched donor blood into small volumes of highly concentrated red cells. These are then delivered through a needle, typically into the umbilical cord, under continuous ultrasound guidance.1
As reported by People, in Arthur’s case, the transfusion was administered through the mother’s uterus into the fetus, restoring oxygen delivery. This helped the excess fluid around his heart and organs to be gradually reabsorbed, allowing normal function to resume.
The experience was absolutely terrifying. The doctor said it was 50/50 whether he would make it or not.Maisie Ransom, Arthur's mother
AS reported by People, she recalled,
The first thing they did was remove some of the fluid around his heart with needles then they gave him the transfusion with a needle into this liver. The doctor had to be incredibly precise and I am still baffled at what she was able to do in that room.Maisie Ransom, Arthur's mother
Severe fetal anemia reduces the oxygen-carrying capacity of blood, which can impair organ function and lead to heart failure.1
In this case, doctors intervened early to restore circulating red blood cells, improve oxygen delivery, and reverse the progression of hydrops. Timely transfusion allowed stabilization of the fetal condition and prevented further complications.
His organs were failing. His heart was completely enveloped in fluid. It was struggling to pump. If nothing was done he would not have made it much longer.Maisie Ransom, Arthur's mother
Doctors informed the family that, to the best of their knowledge, this was one of the earliest gestational ages at which an intrauterine transfusion had been performed, as reported by People.
Arthur has since shown normal growth and development, with his mother reporting that he is meeting expected milestones. She also expressed a desire to thank the donor whose blood contributed to the procedure, acknowledging its role in her child’s survival.
I do often wonder who the person to donate was as I would love to tell them that their decision to give blood gave my boy the chance to be here.Maisie Ransom, Arthur's mother
She later joined NHS Blood and Transplant to formally thank donors involved in such cases.
The transfusion service has identified a small group of donors whose blood has been frequently used in preparing products for intrauterine transfusions. This reflects the limited donor pool eligible for such specialized procedures.
Strict eligibility criteria apply to donors. Individuals must typically be male, have blood group O, be Kell antigen-negative, and test negative for cytomegalovirus. These requirements are essential to minimize the risk of immune reactions and infections in the fetus, which is particularly vulnerable due to its small size and developing immune system.
Collected blood is processed into small volumes of highly concentrated red blood cells, suitable for transfusion into the fetal circulation under ultrasound guidance. In the UK, approximately 180 such units are issued annually, indicating the rarity of the procedure.
As reported by Independent, Dr Anne Kelly, pediatric transfusion and components clinical expert for NHSBT, stated that intrauterine transfusions are performed only in situations where they are necessary to preserve life.
We only supply blood from carefully selected donors and extra safety measures are applied as the patients are particularly vulnerable recipients because of their small size and developmental immaturity.Dr Anne Kelly, Pediatric Transfusion and Components Clinical Expert, NHSBT
As reported by Independent, one of the identified frequent donors, Paul Bickley, said that his motivation to donate blood was influenced by his mother’s example of regular donation, contributing to ongoing support for patients requiring specialized transfusions.
Arthur was born in January 2025 and is currently healthy, with normal growth and developmental milestones.
His mother expressed gratitude to NHS Blood and Transplant and the donors involved, stating that she is deeply thankful for the timely availability of specialised blood and care, which made it possible for her family to have this outcome.
1. Crowe, E. P., R. Hasan, N. H. Saifee, S. Bakhtary, J. L. Miller, J. M. Gonzalez-Velez, and R. Goel. “How Do We Perform Intrauterine Transfusions?” Transfusion 63, no. 12 (December 2023): 2214–2224.