National, 4th February 2026: Rainbow Children’s Heart Institute, Hyderabad, has reported one of the world’s first successful clinical cases of direct fetal immunotherapy to treat immune-mediated fetal myocarditis, a rare and life-threatening heart condition affecting unborn babies. The outcome has placed the hospital among a very small number of centres globally to demonstrate success with this advanced in-utero intervention.

The patient, a 29-year-old expectant mother with Sjögren’s syndrome (an autoimmune disease that damages your moisture-producing glands), had a history of previous fetal loss. At 22 weeks of gestation, fetal echocardiography revealed immune-mediated cardiomyopathy with second-degree heart block, caused by maternal antibodies crossing the placenta and damaging the developing fetal heart. The fetus had a dangerously slow heart rate and weakened cardiac pumping, placing it at high risk of progression to heart failure or fetal demise if left untreated.

Given the severity and rapid progression of the condition, the multidisciplinary team at Rainbow adopted a direct fetal immunotherapy approach, delivering treatment directly to the fetus under advanced imaging guidance. This strategy was chosen because conventional maternal therapy may not reach the fetus in adequate concentration or time in critical cases. Following the intervention, fetal heart function improved dramatically, with recovery of cardiac contractility and normalisation of the heart rate to 150 beats per minute. The baby was delivered at term with a normal heart rhythm and remained clinically stable for post-birth.

Dr. Shweta Bakhru, Paediatric Cardiologist, Rainbow Children’s Heart Institute, said immune-mediated foetal heart disease can deteriorate rapidly and is often detected late because mothers may have no symptoms. “When maternal antibodies cross the placenta and injure the developing foetal heart, the damage can progress very quickly, sometimes leading to heart failure or dangerous rhythm disturbances. In such situations, treating only the mother may not deliver therapy to the baby fast enough. Direct foetal immunotherapy allows us to intervene at a critical moment, target the disease process more effectively, and potentially change the outcome for the baby,” she said.

Dr. Bhargavi Dhulipudi, Paediatric Cardiologist, Rainbow Children’s Heart Institute, emphasised that this approach is reserved for the most severe and carefully selected cases. “This is not routine care. It is a highly specialised intervention used when the disease continues to worsen despite standard maternal treatment and the risk to the baby is very high. Delivering immunotherapy directly to the foetus requires advanced imaging, precise execution, and close monitoring by a multidisciplinary team, but in the right situations, it offers an important option where alternatives are extremely limited,” she said.

Senior Paediatric Cardiologist at Rainbow Children’s Heart Institute, Dr. Nageswara Rao Koneti, highlighted the broader significance of the achievement. “Successfully performing direct foetal immunotherapy places this centre among a small number worldwide with experience in managing severe immune-related foetal heart disease in this way. It demonstrates how targeted, in-utero treatment, guided by advanced imaging, can stabilise rapidly progressing disease and open new possibilities for babies who would otherwise face very high risk,” he said.

The Institute has since treated multiple severe cases using this technique, with encouraging outcomes including improved heart function, reduction in fluid accumulation, and stabilisation of life-threatening rhythm disturbances. All babies were delivered alive and showed reassuring cardiac outcomes on follow-up.

Clinicians believe these early successes could help shape future management of high-risk immune-mediated fetal heart disease in specialised centres, offering new hope to families facing rare and complex prenatal cardiac conditions.

The findings, published in JACC: Case Reports, are based on five foetuses diagnosed between 21 and 27 weeks of gestation with severe cardiac involvement. All five foetuses showed significant improvement following treatment. Abnormal fluid accumulation reduced or resolved, cardiac pumping function improved, and several cases demonstrated normalisation of previously life-threatening rhythm abnormalities. All babies were delivered alive and remained clinically stable after birth, with reassuring cardiac function on follow-up.