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NCT Number: NCT07422181

PlaCEUS: Feasibility Study of Contrast-enhanced Ultrasound to Visualize Maternal Uterine Spiral Arteries Postpartum.

During pregnancy, unique blood vessels form within the uterine wall, known as spiral arteries. These vessels originate from the uterine artery, which is the main artery supplying blood to the uterus. Throughout pregnancy, spiral arteries undergo significant changes to increase blood and oxygen flow to the placenta, ensuring the developing baby receives adequate nutrients. When these arteries fail to remodel properly, complications such as pre-eclampsia or fetal growth restriction can occur.

Until now, direct observation and evaluation of spiral arteries during pregnancy has not been feasible. Contrast-enhanced ultrasound may provide a breakthrough in this area. In this study, the investigators aim to use this imaging technique to visualize spiral arteries after the placenta has been delivered. If successful, this could allow to assess their structural quality. Additionally, the investigators will employ ultrasound to monitor physiological changes in the uterine artery during late pregnancy (after 37 weeks), during labour, and postpartum.

By conducting these measurements, the investigators hope to develop methods for detecting spiral artery abnormalities earlier in pregnancy. Early identification could enable timely interventions and help prevent severe complications.

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Key information

Conditions

Spiral Arteries Contrast Enhanced Ultrasound Doppler Parameters Heart Murmurs Pathological Conditions, Signs and Symptoms Pulsatility Index Resistance Index Signs and Symptoms Systolic Murmurs Systolic/Diastolic Ratio Uterine Artery Hemodynamics

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Máxima Medical center

Veldhoven, 5504DB, Netherlands

Location status: Recruiting

About this study

Adequate blood flow to the placenta is critical for normal fetal development and positive pregnancy outcomes. A key component of this process is the maternal uterine spiral arteries, which undergo significant physiological remodeling during pregnancy to meet the growing demands of the fetus. When this remodeling is impaired, it has been linked to complications such as preeclampsia, fetal growth restriction, and placental abruption.

Despite its importance, directly and non-invasively assessing the maternal uterine microvasculature-particularly spiral arteries-remains difficult. Conventional Doppler ultrasound only provides indirect insights by estimating vascular resistance at a macroscopic level and cannot visualize spiral arteries or directly evaluate placental perfusion. Contrast-enhanced ultrasound (CEUS) represents a promising alternative, as it improves visualization of small vessels through the use of ultrasound contrast agents (UCAs). Since UCAs are currently not approved for use during pregnancy, this study focuses on assessing the feasibility of CEUS for visualizing persistent spiral arteries in the immediate postpartum period, as an initial step toward investigating the maternal side of the placenta. In addition, Doppler waveform analysis of the uterine arteries will be performed at three time points: before delivery, during labor, and after birth. Combining CEUS with Doppler imaging may provide a more comprehensive understanding of dynamic uteroplacental vascular changes around delivery.

The primary objectives are to determine whether maternal uterine spiral arteries remain present after delivery and to evaluate the feasibility of CEUS with UCAs in visualizing and characterizing these arteries within four hours postpartum.

Secondary objectives include assessing uterine artery Doppler parameters before, during, and after delivery to describe peripartum hemodynamic changes, and correlating CEUS findings at four hours postpartum with Doppler measurements.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Pregnant patient at a minimum age of 18 years
  • Singleton pregnancy at term (≥37 weeks gestation)
  • Planning to deliver at the Máxima Medical Centre
  • Able to provide informed consent
  • Intravenous access present at the time of delivery

Exclusion criteria

  • Multiple gestation pregnancy
  • Contra-indications to CEUS, e.g. known allergy for constituents of SonoVue™
  • Planning on breastfeeding
  • Medical emergency during or after delivery, which makes CEUS impossible or undesirable
  • No intravenous access present at the time of delivery
  • Body Mass Index >40 kg/m2.
  • Pre-eclampsia requiring medication
  • Foetal growth restriction < p3

Treatment and study plan

SonoVue (sulphur hexafluoride microbubbles)

Diagnostic Test

SonoVue will be used in this study as ultrasound contrast agents for contrast enhanced ultrasound to assess the feasibility in visualizing and charactering the persistence of maternal uterine spiral arteries within 4 hours postpartum.

Primary outcomes

  1. Number of participants with persisting spiral arteries detected by contrast enhanced ultrasound within 4 hours postpartum.

    Time frame: Within 4 hours postpartum

    Presence of persisting spiral arteries will be assessed using contrast enhanced ultrasound (CEUS) with Sonovue within 4 hours postpartum. The transition of spiral arteries into the intervillous space will be identified at the interface between the decidua and the basal plate of the placenta. Depending on placental location, a sagittal or coronal plane will be selected for optimal visualization. The probe will be positioned perpendicular (90°) to the uteroplacental interface, and color Doppler will be activated to confirm unidirectional flow at the spiral artery opening.

    Persistence of spiral arteries will be determined as a dichotomous outcome. Visbile or not visible. The number of patients will be calculated in whom the result was: visible.

  2. Feasibility of Contrast Enhanced Ultrasound (CEUS) with Sonovue for visualizing spiral arteries within 4 hours postpartum. Dichotomous outcome; visible or invisible spiral arteries.

    Time frame: Within 4 hours postpartum

    Feasibility will be assessed by determining whether CEUS with Sonovue successfully visualizes and characterizes maternal uterine spiral arteries within 4 hours postpartum. A scan will be considered feasible if the transition of spiral arteries into the intervillous space can be identified at the uteroplacental interface using the predefined imaging protocol (correct probe orientation, sagittal/coronal plane selection, and confirmation of unidirectional flow with color Doppler). The outcome is dichotomous. The spiral arteries are visible or not visible.

Secondary outcomes

  1. Change in uterine artery Resistance Index (RI) across peripartum period

    Time frame: Before delivery (after 37 weeks of gestation), during delivery (when in active labour or at the same day prior to a Caesarean delivery), and within 4 hours postpartum.

    Uterine artery resistance index (RI) will be measured using Doppler ultrasound before delivery (after 37 weeks) Uterine artery resistance index (RI) will be measured using Doppler ultrasound during delivery (active labor or same day prior to cesarean) Uterine artery resistance index (RI) will be measured using Doppler ultrasound within 4 hours postpartum.

  2. Change in uterine artery Pulsatility Index (PI) across peripartum period

    Time frame: Before delivery (after 37 weeks of gestation), during delivery (when in active labour or at the same day prior to a Caesarean delivery), and within 4 hours postpartum.

    Uterine artery pulsatility index (PI) will be measured using Doppler ultrasound before delivery (after 37 weeks),

    Uterine artery pulsatility index (PI) will be measured using Doppler ultrasound during delivery (active labor or same day prior to cesarean) Uterine artery pulsatility index (PI) will be measured using Doppler ultrasound within 4 hours postpartum.

    The change in PI will be assesed as delta PI, both absolute as in percentage change of PI.

  3. Change in uterine artery Systolic/Diastolic Ratio across peripartum period

    Time frame: Before delivery (after 37 weeks of gestation), during delivery (when in active labour or at the same day prior to a Caesarean delivery), and within 4 hours postpartum.

    Uterine artery systolic/diastolic ratio will be measured using Doppler ultrasound at three time points: before delivery (after 37 weeks), during delivery (active labor or same day prior to cesarean), and within 4 hours postpartum.

  4. Correlating CEUS findings with uterine artery Doppler parameters within 4 hours postpartum

    Time frame: Within 4 hours postpartum

    Correlation will be assessed between CEUS findings (presence of persisting spiral arteries detected using contrast enhanced ultrasound with Sonovue) and uterine artery Doppler parameters (Resistance Index [RI], Pulsatility Index [PI], and Systolic/Diastolic ratio). CEUS will follow the standardized imaging protocol for spiral artery visualization, and Doppler measurements will be obtained using standard obstetric ultrasound techniques.

Study contacts

Contact information is provided by the study sponsor or research team.

Eveline Dekker, Drs

CONTACT

[email protected]

+3140 888 83 80

Loes Monen, Dr.

CONTACT

+3140 888 83 80

Sponsors and collaborators

Lead sponsor

Maxima Medical Center

Other

Registry information

Acronym: PlaCEUS

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Feb 19, 2026
Registry last updated
Feb 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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