Blood-Filtering Device May Prolong Pregnancy in Severe Early Preeclampsia

In its severe early form, often before 34 weeks’ gestation, clinicians frequently face the dilemma of delivering prematurely to protect the mother while risking complications for the infant. Extending pregnancy safely remains a critical unmet need in obstetric care. To help address this challenge, investigators have introduced a treatment designed to prolong gestation in severe early preeclampsia.

Researchers at Cedars-Sinai Health Sciences University developed a blood-filtering treatment intended for patients with severe early disease. The early-stage international pilot trial was published in Nature Medicine in 2026. The approach was created to delay delivery while maintaining maternal stability and fetal growth. The strategy focuses on removing a circulating factor implicated in the disorder.

The treatment targets soluble fms-like tyrosine kinase 1 (sFlt-1), a placental protein that damages the vasculature and drives preeclampsia symptoms. Investigators engineered an immune protein that binds sFlt-1 and integrated it into a blood-filtering device. Using extracorporeal apheresis, a procedure similar to kidney dialysis, the system filters maternal blood to remove excess sFlt-1 while preserving other essential blood components. The intention is to reduce pathologic signaling without exposing the mother or fetus to new pharmacologic agents.

In the study, 16 pregnant patients received the treatment. Investigators reported improvements in maternal blood pressure during therapy. Fetuses continued to grow normally while treatment was administered. On average, pregnancy was prolonged by 10 additional days compared with untreated patients, more than doubling the time typically achieved without intervention. The added days were described as providing crucial time for fetal development prior to birth.

The authors emphasized that the platform removes a harmful factor rather than adding medications, which may reduce the risk of adverse drug effects. They also cautioned that the findings are preliminary. The therapy remains experimental and requires evaluation in larger clinical trials to define safety, efficacy, and practical implementation.

“Right now, the only way to cure preeclampsia and protect the life and health of the mother is to deliver the baby. That puts very premature infants at high risk. This approach could give clinicians more flexibility in managing these high-risk cases,” said Sarah Kilpatrick, M.D., Ph.D., expert in maternal-fetal medicine and chair of the Department of Obstetrics and Gynecology at Cedars-Sinai.

“Even a few extra days in the womb can make a meaningful difference in outcomes for premature infants. We found a way to potentially buy that time safely. Our approach could shift how we manage very early preeclampsia,” said Ananth Karumanchi, M.D., professor of Medicine, director of the Renovascular Research Center and the Medallion Chair in Vascular Biology at Cedars-Sinai.

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