Photoplethysmography in hypertensive disorders of pregnancy
Research type
Research Study
Full title
Pilot study investigating the use of photoplethysmography in hypertensive disorders of pregnancy
IRAS ID
362170
Contact name
Christina Yu
Contact email
Sponsor organisation
Imperial College London
Clinicaltrials.gov Identifier
N/a , N/a
Duration of Study in the UK
0 years, 11 months, 30 days
Research summary
Hypertensive disorders of pregnancy (HDP) affect 8–10% of pregnancies and exist on a spectrum, with preeclampsia representing the most severe form. Identifying which women with hypertension will progress to preeclampsia and experience serious maternal or fetal complications remains a major clinical challenge. Current prediction models—using maternal characteristics, pressure, uterine artery Doppler, and angiogenic biomarkers—offer only modest accuracy and depend on laboratory testing or specialised ultrasound expertise, limiting their feasibility where the burden of HDP is highest.
The ophthalmic artery (OA) Doppler is a novel approach for assessing maternal cerebrovascular haemodynamics. Its waveform includes two systolic peaks (PSV1 and PSV2). The OA peak systolic velocity ratio (PSV2/PSV1) has shown predictive performance similar to anti-angiogenic biomarkers in multivariate models. Among women with hypertension, this ratio can help distinguish preeclampsia from gestational or chronic hypertension, reflecting differences in vascular adaptation. However, OA Doppler still requires ultrasound imaging and trained operators, limiting widespread implementation.
Photoplethysmography (PPG) offers a low-cost, non-invasive alternative that captures waveform features analogous to the OA Doppler. PPG measures blood-volume changes using light absorption and is already integrated into pulse oximeters and wearable devices. New applications, such as the D-SCAPE wearable PPG system, use raw time-series signals and deep learning to estimate blood pressure and monitor haemodynamic status in real time. Early research suggests that PPG-derived features may support prediction of blood pressure changes, evolving preeclampsia, and even differentiation of severe preeclampsia from normotension. However, the behaviour of the PPG waveform pregnancy, particularly in different hypertensive states, remains poorly characterised.
Given its accessibility, affordability, and ability to capture haemodynamic information similar to OA Doppler, PPG may offer a scalable tool for screening and risk stratification in HDP. This study aims to characterise PPG waveforms in normotensive and hypertensive pregnancies, compare their behaviour to the OA Doppler PSV ratio and assess device acceptability among pregnant women.
REC name
East Midlands - Derby Research Ethics Committee
REC reference
26/EM/0098
Date of REC Opinion
8 May 2026
REC opinion
Favourable Opinion