A wearable ultrasound patch developed by researchers at the University of Oxford, in collaboration with teams at the University of California San Diego and Stanford University, could help doctors monitor fetal health continuously and detect warning signs in high-risk pregnancies earlier.
The technology, described in a study published in Nature Biotechnology, addresses a major limitation in current pregnancy care, where doctors rely largely on intermittent ultrasound scans that provide only momentary snapshots of a baby’s wellbeing. Researchers say important changes can be missed between appointments, particularly in pregnancies complicated by pre-eclampsia, hypertension, gestational diabetes or poor fetal growth.
The soft wearable device, called UPatch, sits on the mother’s abdomen and continuously tracks fetal anatomy and blood flow over extended periods. Software integrated into the system automatically follows blood vessels even when the mother or baby moves, removing the need for constant supervision by an expert sonographer.
The study was led by Professor Antoniya Georgieva, founder of Safer Birth Ltd and head of the Oxford Labour Monitoring research team at the Nuffield Department of Women’s and Reproductive Health. She collaborated with Professor Sheng Xu and Dr Tom Park from teams at the University of California San Diego and Stanford University.
Researchers developed 14 prototype versions of the patch before arriving at the current design. The technology was originally intended for monitoring blood pressure in adult coma patients in intensive care units, but had to be redesigned extensively for use in pregnancy, where both the mother and fetus are constantly moving.
The device was tested in 62 pregnancies and showed strong agreement with standard clinical ultrasound systems used for fetal biometry and obstetric assessments. Researchers also carried out continuous monitoring sessions lasting between one and six hours in 52 pregnant women, including women with high-risk pregnancies.
According to the study, the patch was able to continuously detect changes in fetal blood flow linked to placental insufficiency or developing fetal compromise. In one severe pre-eclampsia case, the device identified concerning abnormalities in blood flow, prompting intensified monitoring and delivery by Caesarean section four days later.
Researchers believe the technology could help clinicians distinguish between temporary fluctuations and sustained signs of fetal distress, potentially allowing earlier intervention while reducing unnecessary hospital visits and repeat scans.
“Babies in the womb still cannot be monitored reliably which is a major gap in maternity care worldwide, with huge implications. Solutions are needed urgently,” Prof. Georgieva said. She added that the technology could help clinicians identify problems earlier and improve understanding of how babies adapt to changing oxygen supply inside the womb.
Prof. Xu said the study demonstrated how advances in soft electronics, ultrasound engineering and clinical science could address “one of the most important unmet needs in pregnancy care”.
Dr Park said the device could improve access to prenatal imaging in low-resource settings and healthcare deserts where shortages of trained sonographers often delay care for high-risk pregnancies.
Mariana Tome, an obstetric doctor and co-author from the Nuffield Department of Women’s and Reproductive Health, said the technology had the potential to transform pregnancy care by helping women feel safer and reducing avoidable interventions, repeated scans and unnecessary hospital visits.
Researchers said the patch may prove particularly useful in monitoring pregnancies affected by fetal growth restriction, hypertension and pre-eclampsia, conditions associated with reduced oxygen supply and placental dysfunction that can increase the risk of stillbirth and other serious complications.
The work was supported by Wellcome Leap through its In Utero programme, which focuses on scalable technologies to better understand fetal development during pregnancy.
While the current version still relies on a wired backend setup, researchers said future miniaturised electronics could eventually make the system fully wireless and suitable for wider use in hospitals and community settings.
