First baby born in global study to prevent fetal blood disorder

The study is being conducted by the Pregnancy and Childbirth Medical Unit at Karolinska University Hospital, in collaboration with a pharmaceutical company. It is a double-blind, randomized, placebo-controlled trial evaluating the safety and efficacy of the drug nipocalimab in preventing fetal and neonatal alloimmune thrombocytopenia (FNAIT). This is a rare but potentially life-threatening condition in which the mother’s immune system attacks the fetus’s platelets.

“It’s rare to see clinical drug trials that target the fetus during pregnancy, so this represents a major leap forward,” said Dr. Gunilla Ajne, Senior Consultant at the Pregnancy and Childbirth Medical Unit at Karolinska University Hospital and Associate Professor at the Department of Obstetrics and Gynecology at Karolinska Institutet.

She adds, “It’s an incredible milestone that we now have the first baby in the world born within the framework of this study—and both mother and child are doing well.”

A Serious but Rare Condition

Approximately 0.5 percent of all pregnant women develop antibodies that can affect the fetus, a process known as alloimmunization. In the most severe cases, around 0.1 percent, this can lead to FNAIT, where the fetus’s platelets are destroyed, increasing the risk of severe bleeding. It may also lead to a form of anemia where the fetus’s red blood cells are broken down, known as hemolytic disease of the fetus and newborn (HDFN).

The drug being tested works by blocking the harmful antibodies in the mother’s blood, preventing them from crossing the placenta and attacking the fetus’s platelets. Since the study is double-blinded, participants receive either the active drug or a placebo—without anyone knowing which.

National Center for In-Utero Treatment

Karolinska University Hospital is currently the national center in Sweden for intrauterine transfusions (IUT), a specialized treatment in which a fetus receives blood transfusions directly in the womb due to anemia. This highly advanced procedure often needs to be repeated every two weeks until delivery and requires expectant mothers from across the country to travel to Karolinska for care.

“If the drug proves effective, it could pave the way for an entirely new treatment approach,” said Dr. Ajne.

She continued:

“Ideally, we could prevent the baby from becoming ill or needing intensive neonatal care. It could also mean that treatment can be administered locally in the mother’s home region, offering greater security, reducing travel, and placing less strain on the family.”

A global study – but Karolinska leads the way

A total of 39 pregnant women are expected to participate in the FREESIA-1 trial, which is being conducted across about 15 European countries, as well as in the United States, Canada, and South America. Karolinska plans to include three women in this initial phase, and an additional 3–6 in a follow-up study focusing on fetal red blood cells.

The study is part of the Pregnancy and Childbirth Medical Unit at Karolinska University Hospital. Dr. Gunilla Ajne is also affiliated with the Department of Clinical Science, Intervention and Technology (CLINTEC), Division of Obstetrics and Gynecology at Karolinska Institutet.

“This research has the potential to transform future treatments for a group of pregnant women for whom we currently have very limited options to prevent serious complications in their babies,” Dr. Ajne added.

Text: Henrik Pehrsson
Photo: Mattias Ramström (private)