An interventional study of SonoVue (sulphur hexafluoride microbubbles) in Spiral Arteries, Uterine Artery Hemodynamics and Contrast Enhanced Ultrasound, sponsored by Maxima Medical Center. Recruiting at 1 site in Netherlands. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-19.
Sponsored by Maxima Medical Center · Not applicable, Interventional, and Diagnostic
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.
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.
Maxima Medical Center is the lead sponsor of 29 studies on the registry; 15 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
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BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants included in the study will receive contrast enhanced ultrasound imaging postpartum. During pregnancy, during labour and postpartum Doppler parameters of the uterine arterie will be performed.
Diagnostic Test: SonoVue (sulphur hexafluoride microbubbles)
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.
Number of participants with persisting spiral arteries detected by contrast enhanced ultrasound 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.
Time frame: Within 4 hours postpartum
Feasibility of Contrast Enhanced Ultrasound (CEUS) with Sonovue for visualizing spiral arteries within 4 hours postpartum. Dichotomous outcome; visible or invisible spiral arteries.
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.
Time frame: Within 4 hours postpartum
Change in uterine artery Resistance Index (RI) across peripartum period
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.
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.
Change in uterine artery Pulsatility Index (PI) across peripartum period
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.
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.
Change in uterine artery Systolic/Diastolic Ratio across peripartum period
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.
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.
Correlating CEUS findings with uterine artery Doppler parameters 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.
Time frame: Within 4 hours postpartum
Plan to share: No — All participant will sign informed consent stating that all data will be used anonymously.
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Systolic Murmurs
Maxima Medical Center