Labor PainNCT06655675
Changes in Velocimetric Indices of Uterine and Umbilical Arteries Before and After Combined Spinal-epidural Analgesia in Laboring Women (PART II)
A study testing Ultrasound in people with Labor Pain, run by Samuel Lunenfeld Research Institute, Mount Sinai Hospital at 1 site in Canada.
Trial summary
Combined spinal-epidural (CSE) for labor analgesia has been used for many years and is practiced commonly at our institution, especially when the patient requests immediate pain relief. Read more about this study
- Who is it for?
- Ages 18 to 50 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Labor Pain
- What is being tested?
- Ultrasound
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 54 participants
- Where
- 1 siteCanada
- Study dates
- 30 Oct 2024to Jan 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Written informed consent
- Term pregnant patients requesting labor analgesia
- Singleton pregnancy
- Term pregnant patients in active labor
- ASA<4
- No evidence of fetal congenital anomalies, fetal compromise or fetal decelerations prior to CSE
- Patients with and without diagnosed hypertensive disorders of pregnancy
Who cannot join
- Refusal to consent for the study
- Known spinal deformities
- Previous back instrumentation
- Patients with BMI>50 kg/㎡ due to anticipated technical challenges in Doppler studies
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
Mount Sinai Hospital
Toronto, Ontario, M5G1X5
Mrinalini Balki, MD, 416-586-4800 ext. 5270, mrinalini.balki@uhn.ca
Javiera Vargas Zuniga, MD
About this study
Official title: Changes in Velocimetric Indices of Uterine and Umbilical Arteries Before and After Combined Spinal-epidural Analgesia in Laboring Women (PART I and PART II)
Combined spinal-epidural (CSE) for labor analgesia has been used for many years and is practiced commonly at our institution, especially when the patient requests immediate pain relief. CSE is not only beneficial for its faster onset of analgesia, but also it is favorable in relation to the need for rescue analgesia, urinary retention, and rate of instrumental delivery compared to the traditional epidural. Despite its beneficial effects, there is a risk of about 15-30% of developing abnormal fetal heart rate following CSE. This is self-resolving with minimal or no intervention. Although the cause of fetal bradycardia is not fully elucidated, variations in uterine artery blood flow after epidural analgesia are thought to be due to the interaction of numerous events related to blockade of sympathetic innervations, fluid administration, maternal hypotension, uterine vascular effects of sympathetic block, fluctuations in circulating catecholamines, and possibly the effect of opioids. Similar mechanism is thought to be a cause of fetal bradycardia after the CSE with its faster onset and superior block.
Maternal or fetal circulation during labor can be assessed using continuous-wave Doppler ultrasound to monitor maternal uterine artery (UtA) and fetal umbilical artery (UmA) velocity waveforms to detect changes in blood flow. The velocimetry indices mentioned above have been often used to assess the changes in the blood flow before and after the induction of epidural analgesia during labor in several studies. Although there are some studies regarding the effect of labor epidural analgesia using velocimetry indices, but there is currently no published study evaluating velocimetry indices of uterine and umbilical arteries before and after the induction of CSE. Thus, the aim of this study is to investigate the impact of CSE to maternal and fetal blood flow to evaluate the relationships.
The investigators hypothesize that both uterine artery and umbilical artery blood flow are reduced after the induction of CSE, which may be responsible for the occurrence of fetal bradycardia.
- Conditions
- Labor Pain
- Being tested
- Ultrasound
- Keywords
- combined spinal epidural (CSE), fetal bradycardia, ultrasound, velocimetric index, hypertension
- Medical subject headings
- Labor Pain, Hypertension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
UltrasoundDevice
Ultrasound scan of the umbilical artery
| Study group | Role | What they receive |
|---|---|---|
| Ultrasound - patients without hypertensive disorders of pregnancy | Experimental | Ultrasound will be used to measure velocimetric index of the umbilical artery. Receives: Device: Ultrasound |
| Ultrasound - patients with diagnosed hypertensive disorders of pregnancy | Experimental | Ultrasound will be used to measure velocimetric index of the umbilical artery. Receives: Device: Ultrasound |
What is being measured
The primary outcome is the main question the study is designed to answer.
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 10 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 10 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 10 minutes
Umbilical artery velocimetric index - pulsatility index (PI) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 10 minutes
Umbilical artery velocimetric index - resistance index (RI) at 10 minutes
Umbilical artery velocimetric index - resistance index (RI) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 10 minutes
Secondary outcomes (34)
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at baseline
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured prior to combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at baseline
Umbilical artery velocimetric index - pulsatility index (PI) will be measured prior to combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - resistance index (RI) at baseline
Umbilical artery velocimetric index - resistance index (RI) will be measured prior to combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 5 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured 5 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI)will be measured 5 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - resistance index (RI) at 5 minutes
Umbilical artery velocimetric index - resistance index (RI) will be measured 5 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 20 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured 20 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 20 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 20 minutes
Umbilical artery velocimetric index - pulsatility index (PI) will be measured 20 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 20 minutes
Umbilical artery velocimetric index - resistance index (RI) at 20 minutes
Umbilical artery velocimetric index - resistance index (RI) will be measured 20 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 20 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 30 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured 30 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 30 minutes
Umbilical artery velocimetric index - pulsatility index (PI) will be measured 30 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 30 minutes
Umbilical artery velocimetric index - resistance index (RI) at 30 minutes
Umbilical artery velocimetric index - resistance index (RI) will be measured 30 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Measured: 30 minutes
Pain score at baseline - questionnaire
Pain score - verbal numeric rating scale (0-10) prior to combined spinal epidural
Measured: 1 minute
Pain score at 10 minutes - questionnaire
Pain score - verbal numeric rating scale (0-10) at 10 minute after combined spinal epidural
Measured: 10 minutes
Pain score at 30 minutes - questionnaire
Pain score - verbal numeric rating scale (0-10) at 30 minute3 after combined spinal epidural
Measured: 30 minutes
Sensory block level at 10 minutes
Sensory block level at 10 minutes following combined spinal epidural
Measured: 10 minutes
Sensory block level at 30 minutes
Sensory block level at 30 minutes following combined spinal epidural
Measured: 30 minutes
frequency of uterine contractions
The number of contractions on the monitor in a 10 minute period.
Measured: 10 minutes
Presence of prolonged hypertonic uterine contractions- questionnaire
Presence of prolonged hypertonic uterine contractions as measured by the monitor
Measured: 30 minutes
Hypotension: systolic blood pressure less than 80% of baseline
Systolic blood pressure < 80% of baseline, monitored q5 for 30 minutes following combined spinal epidural
Measured: 30 minutes
Hypertension: systolic blood pressure greater than 120% of baseline
Systolic blood pressure > 120% of baseline, monitored q5 for 30 minutes following combined spinal epidural
Measured: 30 minutes
Bradycardia: heart rate less than 70% of baseline
Heart rate < 70% of baseline or a heart rate < 50bpm, monitored q5 for 30 minutes following combined spinal epidural
Measured: 30 minutes
Desaturation: oxygen level <95%
Oxygen level <95%, monitored q5 for 30 minutes following combined spinal epidural
Measured: 30 minutes
fetal heart rate at baseline
fetal heart rate at baseline, prior to combined spinal epidural
Measured: 5 minutes
fetal heart rate q5 min up to 30 minutes
fetal heart rate q5 min up to 30 minutes following combined spinal epidural
Measured: 30 minutes
presence of fetal bradycardia - questionnaire
presence of fetal bradycardia (fetal heart rate <110)
Measured: 30 minutes
presence of fetal prolonged deceleration - questionnaire
presence of fetal prolonged deceleration (fetal heart rate <110/min lasting less than 10 minutes)
Measured: 30 minutes
presence of fetal persistent late decelerations - questionnaire
presence of fetal persistent late decelerations will be recorded
Measured: 30 minutes
presence of fetal non-reassuring variable deceleration - questionnaire
presence of fetal non-reassuring variable deceleration will be recorded
Measured: 30 minutes
presence of fetal salutatory variability - questionnaire
presence of fetal salutatory variability (FHR change>25beats) will be recorded
Measured: 30 minutes
Neonatal weight
Neonatal weight measured after delivery in grams minutes
Measured: up to 24 hours
Apgar score at 1 minute
Apgar score at 1 minute
Measured: 1 minute
Apgar score at 5 minutes
Apgar score at 5 minutes
Measured: 5 minutes
Mode of delivery - questionnaire
Mode of delivery will be recorded as vaginal, assisted (forceps or vacuum), or cesarean
Measured: up to 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Oct 2024
- Study start30 Oct 2024
- Primary completionJan 2026 (estimated)
- Study completionJan 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Labor PainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 54 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Mrinalini Balki, MD, Principal investigator, MOUNT SINAI HOSPITAL
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06655675
- Sponsor's protocol ID
- 24-09
- Status last verified
- Jul 2025
- First submitted
- 17 Oct 2024
- Last updated
- 11 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Changes in Velocimetric Indices of Uterine and Umbilical Arteries Before and After Combined Spinal-epidural Analgesia in Laboring Women (PART I and PART II)
- ClinicalTrials.gov ID
- NCT06655675
- Acronym / sponsor ID
- 24-09
- Conditions
- Labor Pain
- Keywords
- combined spinal epidural (CSE), fetal bradycardia, ultrasound, velocimetric index, hypertension
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 54 participants (estimated)
- Lead sponsor
- Samuel Lunenfeld Research Institute, Mount Sinai HospitalUniversity, hospital or other
- Study start
- 30 Oct 2024 (actual)
- Primary completion
- Jan 2026 (estimated)
- Study completion
- Jan 2026 (estimated)
- First posted
- 23 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Combined spinal-epidural (CSE) for labor analgesia has been used for many years and is practiced commonly at our institution, especially when the patient requests immediate pain relief. CSE is not only beneficial for its faster onset of analgesia, but also it is favorable in relation to the need for rescue analgesia, urinary retention, and rate of instrumental delivery compared to the traditional epidural. Despite its beneficial effects, there is a risk of about 15-30% of developing abnormal fetal heart rate following CSE. This is self-resolving with minimal or no intervention. Although the cause of fetal bradycardia is not fully elucidated, variations in uterine artery blood flow after epidural analgesia are thought to be due to the interaction of numerous events related to blockade of sympathetic innervations, fluid administration, maternal hypotension, uterine vascular effects of sympathetic block, fluctuations in circulating catecholamines, and possibly the effect of opioids. Similar mechanism is thought to be a cause of fetal bradycardia after the CSE with its faster onset and superior block.
Maternal or fetal circulation during labor can be assessed using continuous-wave Doppler ultrasound to monitor maternal uterine artery (UtA) and fetal umbilical artery (UmA) velocity waveforms to detect changes in blood flow. The velocimetry indices mentioned above have been often used to assess the changes in the blood flow before and after the induction of epidural analgesia during labor in several studies. Although there are some studies regarding the effect of labor epidural analgesia using velocimetry indices, but there is currently no published study evaluating velocimetry indices of uterine and umbilical arteries before and after the induction of CSE. Thus, the aim of this study is to investigate the impact of CSE to maternal and fetal blood flow to evaluate the relationships.
The investigators hypothesize that both uterine artery and umbilical artery blood flow are reduced after the induction of CSE, which may be responsible for the occurrence of fetal bradycardia.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Ultrasound - patients without hypertensive disorders of pregnancy | Experimental | Device: UltrasoundUltrasound will be used to measure velocimetric index of the umbilical artery. |
| Ultrasound - patients with diagnosed hypertensive disorders of pregnancy | Experimental | Device: UltrasoundUltrasound will be used to measure velocimetric index of the umbilical artery. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Written informed consent
- Term pregnant patients requesting labor analgesia
- Singleton pregnancy
- Term pregnant patients in active labor
- ASA<4
Key exclusion criteria (4 listed)
- Refusal to consent for the study
- Known spinal deformities
- Previous back instrumentation
- Patients with BMI>50 kg/㎡ due to anticipated technical challenges in Doppler studies
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| UltrasoundUltrasound scan of the umbilical artery | Device | Ultrasound - patients with diagnosed hypertensive disorders of pregnancy, Ultrasound - patients without hypertensive disorders of pregnancy |
Primary outcome
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 10 minutes
Time frame: 10 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Umbilical artery velocimetric index - pulsatility index (PI) at 10 minutes
Time frame: 10 minutes
Umbilical artery velocimetric index - pulsatility index (PI) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
Umbilical artery velocimetric index - resistance index (RI) at 10 minutes
Time frame: 10 minutes
Umbilical artery velocimetric index - resistance index (RI) will be measured 10 minutes after combined spinal epidural, with the uterus in relaxed and contracted states.
34 secondary outcomes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at baseline
Time frame: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at baseline
Time frame: 5 minutes
Umbilical artery velocimetric index - resistance index (RI) at baseline
Time frame: 5 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 5 minutes
Time frame: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 5 minutes
Time frame: 5 minutes
Umbilical artery velocimetric index - resistance index (RI) at 5 minutes
Time frame: 5 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 20 minutes
Time frame: 20 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 20 minutes
Time frame: 20 minutes
Umbilical artery velocimetric index - resistance index (RI) at 20 minutes
Time frame: 20 minutes
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 30 minutes
Time frame: 5 minutes
Umbilical artery velocimetric index - pulsatility index (PI) at 30 minutes
Time frame: 30 minutes
Umbilical artery velocimetric index - resistance index (RI) at 30 minutes
Time frame: 30 minutes
Pain score at baseline - questionnaire
Time frame: 1 minute
Pain score at 10 minutes - questionnaire
Time frame: 10 minutes
Pain score at 30 minutes - questionnaire
Time frame: 30 minutes
Sensory block level at 10 minutes
Time frame: 10 minutes
Sensory block level at 30 minutes
Time frame: 30 minutes
frequency of uterine contractions
Time frame: 10 minutes
Presence of prolonged hypertonic uterine contractions- questionnaire
Time frame: 30 minutes
Hypotension: systolic blood pressure less than 80% of baseline
Time frame: 30 minutes
Hypertension: systolic blood pressure greater than 120% of baseline
Time frame: 30 minutes
Bradycardia: heart rate less than 70% of baseline
Time frame: 30 minutes
Desaturation: oxygen level <95%
Time frame: 30 minutes
fetal heart rate at baseline
Time frame: 5 minutes
fetal heart rate q5 min up to 30 minutes
Time frame: 30 minutes
presence of fetal bradycardia - questionnaire
Time frame: 30 minutes
presence of fetal prolonged deceleration - questionnaire
Time frame: 30 minutes
presence of fetal persistent late decelerations - questionnaire
Time frame: 30 minutes
presence of fetal non-reassuring variable deceleration - questionnaire
Time frame: 30 minutes
presence of fetal salutatory variability - questionnaire
Time frame: 30 minutes
Neonatal weight
Time frame: up to 24 hours
Apgar score at 1 minute
Time frame: 1 minute
Apgar score at 5 minutes
Time frame: 5 minutes
Mode of delivery - questionnaire
Time frame: up to 24 hours
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Jul 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Mrinalini Balki, MD principal investigator
MOUNT SINAI HOSPITAL
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Ultrasound in people with Labor Pain, run by Samuel Lunenfeld Research Institute, Mount Sinai Hospital at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 11 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mrinalini Balki, MD (416-586-4800 ext. 5270, mrinalini.balki@uhn.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 10 minutes (time frame: 10 minutes). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Jul 2025.