en.Wedoany.com Reported - A soft, adhesive ultrasound patch can continuously track fetal blood flow and structure, a study published in *Nature Biotechnology* that may help clinicians detect complications earlier in high-risk pregnancies.
The device, named UPatch, was developed by engineers at the University of California San Diego (UCSD) in collaboration with the University of Oxford. Unlike conventional obstetric ultrasound, which provides brief, intermittent scans during clinic visits, UPatch is designed for continuous, hands-free monitoring without the need for a sonographer. Geonho (Tom) Park, a doctoral student in chemical and nanoengineering at UCSD and first author of the study, stated that this technology has the potential to democratize access to fetal monitoring, particularly in resource-limited settings with limited specialized care. Abdulla Al-Khan, M.D., vice chair and department director of obstetrics, gynecology, and women's health at Hackensack University Medical Center in New Jersey, who was not involved in the study, called the technology promising but still in its early stages, emphasizing the need for further validation before routine clinical use.
The flexible adhesive patch, placed on the mother's abdomen, uses ultrasound to assess fetal structure and blood flow, including the umbilical cord and major fetal vessels. It works by sending small electrical pulses to ultrasound transducers in the patch, generating sound waves that travel through maternal tissue, reflect off fetal structures, and return to the same transducers. These signals are transmitted via a wired connection to an external computer for real-time imaging and blood flow analysis. An autonomous algorithm continuously tracks the umbilical cord and monitors blood flow for hours, even if the mother or fetus moves. No sonographer is needed to reposition the probe, though initial placement is required. Signals are processed by the wired computer for real-time analysis.
Park explained that fetal physiology is highly dynamic and can change within minutes or hours. Some complications occur intermittently and may go undetected between scan intervals, sometimes leading to fetal injury or death. He stated that the research goal was to create a system capable of monitoring fetal health in real time, rather than relying on isolated assessments.
The system performed similarly to sonographer measurements, with over 90% of readings within 2 millimeters of the target location and image accuracy exceeding 91%, even during continuous movement. Researchers evaluated UPatch in 62 pregnancies at UCSD Health and the University of Oxford, including normal pregnancies and those complicated by preeclampsia, gestational hypertension, gestational diabetes, fetal growth restriction, and extreme body size. Continuous monitoring was performed on 52 women, with measurements taken every 15 seconds. UPatch showed strong agreement with handheld ultrasound, demonstrating high correlations with fetal heart rate (r = 0.94) and blood flow ratio (r = 0.86), and only minor differences in fetal biometric measurements, including head and abdominal measurements, limb length, and estimated fetal weight. During continuous monitoring, Doppler blood flow measurements showed more consistent patterns with gestational age, helping to distinguish high-risk pregnancies from healthy ones. In contrast, fetal heart rate showed substantial overlap across groups.
Park noted that one of the most striking observations was the dynamic changes in fetal blood flow patterns over time, which are difficult to capture with conventional intermittent scans. Repeated measurements over time also help differentiate short-term fluctuations from more persistent changes that may indicate fetal or placental insufficiency. In one case, UPatch detected persistently abnormal blood flow patterns consistent with placental dysfunction in a woman with preeclampsia at 28 weeks and 3 days. Park initially thought there might be a technical issue with the device because the results were so abnormal, but after careful examination, the abnormality was confirmed and the clinical team was immediately notified. The patient was transferred to a higher level of care and delivered by cesarean section 4 days later at 29 weeks. The infant required intensive care but recovered. Researchers believe that continuous monitoring enabled timely detection of severe intrauterine growth restriction and may have prevented stillbirth.
However, Al-Khan cautioned that not every abnormal signal detected through continuous monitoring should trigger an intervention. He stated that an abnormal signal on the screen does not tell clinicians whether to act, when to act, or how urgent the situation is. Without a clear escalation pathway, this could lead to unnecessary interventions, including preterm birth and its complications. The current UPatch is wired, limiting its use to inpatient settings, and requires an initial scan to ensure proper placement. A wireless version is under development, and future iterations are expected to integrate maternal signals such as blood pressure and oxygen saturation to improve risk assessment. Reference ranges for continuous fetal monitoring have not yet been established, making interpretation a core challenge. Park noted that continuous fetal blood flow monitoring on this scale has not been performed before, and it remains necessary to define what level of variation is normal and what signals indicate risk. Al-Khan agreed that this uncertainty is a barrier to safe clinical application and emphasized that widespread adoption without further validation is premature.
The study was supported by Wellcome Leap (HER01430), the National Institutes of Health (1R01EB033464-01 and 1R01HL171652-01), and the Accelerating Innovation to Market program at UCSD. Sheng Xu reports being a co-founder of Softsonics LLC. Mariana Tome, Lawrence Impey, and Antoniya Georgieva from the University of Oxford report being co-founders of Safer Birth Ltd. Aris T. Papageorghiou, also from the University of Oxford, reports being a senior scientific advisor to Intelligent Ultrasound Ltd. All other authors report no relevant conflicts of interest.
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