A dangerous pregnancy complication that causes a sudden spike in the mother's blood pressure and can quickly lead to organ failure and death. The only known treatment has been to deliver the baby fast, often by emergency Caesarean section. If the pregnancy is 32 weeks or less along—as is the case for roughly 20,000 births in America each year—the baby's chances of survival and healthy development are significantly lower.
Doctors have been managing pre-eclampsia in much the same way for the past 50 years. The standard of care is watchful waiting, interspersed with drugs to prevent seizures in the mother and steroids to prepare the baby's lungs for an early birth. Such steps can buy a few additional days but cannot stop the disease's progression.
Scientists have known for about 15 years that a protein called soluble Fms-like tyrosine kinase 1 (sFlt-1), secreted by the placenta to boost blood flow, spikes in pre-eclampsia and plays a direct causal role in the development of the disease. Developing new medicines for pregnant women is difficult, because some molecules could cross from the mother's bloodstream into the placenta and affect the fetus.
In April 2026 an international collaboration led by Ravi Thadhani and Ananth Karumanchi from the Cedars-Sinai Medical Centre in Los Angeles reported in Nature Medicine the early results of a novel treatment that sidesteps this problem by removing problematic components from a woman's blood rather than adding anything new. The technique uses aphaeresis—a standard medical protocol long used to reduce cholesterol levels and remove dangerous blood cells—equipped with a filter armed with antibodies designed to bind specifically to sFlt-1. Although sFlt-1 rebounded in some patients, its level plateaued rather than continuing to rise as would otherwise have been the case.
The trial tested the treatment in only 16 women, but neither the mothers nor their babies had any ill effects. The median extension of pregnancy in the treated women was ten days—meaningfully longer than the four days current treatment offers, and long enough for some babies to be classified as "moderately" rather than "very" preterm. James Walker from the University of Leeds called it "the first credible step beyond symptom control toward a true disease-modifying treatment".
Regression analysis: Mathematical techniques for trying to understand why things are getting worse.