Utero Stem Cell Transplant

“An in utero stem cell transplant for a critically ill second-trimester fetus has led to the birth of an apparently healthy infant. The newborn is the first patient enrolled in the world’s first clinical trial using stem cells transplanted prior to birth.
The infant was born at UCSF Benioff Children’s Hospital San Francisco in February, four months after undergoing the transplant to treat a lethal form of thalassemia, a disease caused by a gene carried by nearly 5 percent of the world’s population.

“It is too early to say how effective the stem cell transplantation will be, but we are encouraged by how well she and her mother have tolerated the treatment,” said Tippi MacKenzie, MD, a pediatric and fetal surgeon at UCSF Benioff Children’s Hospital San Francisco, who performed the pioneering transplant after decades of research. “Her healthy birth suggests that fetal therapy is a viable option to offer to families with this diagnosis.”Unique

Expertise From UCSF Benioff Children’s Hospitals

The infant, whose parents were unknowingly carriers of the disease, was born at 37 weeks’ gestation weighing just under 5 lbs. She has been discharged from the hospital and has returned with her family to their home in Hawaii.
During pregnancy, MacKenzie’s team at the UCSF Fetal Treatment Center treated the fetus with regular in utero blood transfusions, after a medical center near the family’s hometown detected life-threatening swelling, or hydrops, during an ultrasound. The swelling, which included an enlarged heart, was the result of the body’s response to severe anemia and lack of oxygen, which is the hallmark of alpha thalassemia major, the most dangerous variant of the disease.

The fetus’s poor prognosis improved slowly with each transfusion during the pregnancy, Gonzalez Velez said. The stem cell transplant took place during one of those transfusions.


The procedure brings together the unique expertise of both UCSF Benioff Children’s Hospitals. The UCSF Fetal Treatment Center, in San Francisco, is the birthplace of fetal surgery and continues to offer life-saving interventions for fetuses with multiple birth defects. UCSF Benioff Children’s Hospital Oakland established its thalassemia program in 1991 to provide multidisciplinary care to the growing number of thalassemia patients. It is an international leader in stem cell and gene therapy for beta thalassemia.