Changes in Velocimetric Indices of Uterine and Umbilical Arteries Before and After Combined Spinal-epidural Analgesia in Laboring Women (PART II)

NCT06655675 | Recruiting

• 1 other identifier: 24-09
• Study Type: interventional
• Target: 54
• Locations: 1 country
• Sites: 1

Brief 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. 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

Keywords

combined spinal epidural (CSE); fetal bradycardia; ultrasound; velocimetric index; hypertension

Outcome Measures

Primary Outcomes (3)

• 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.

  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.

  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.

  10 minutes

Secondary Outcomes (34)

• Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at baseline

  5 minutes

• Umbilical artery velocimetric index - pulsatility index (PI) at baseline

  5 minutes

• Umbilical artery velocimetric index - resistance index (RI) at baseline

  5 minutes

• Umbilical artery velocimetric index - systolic/diastolic ratio (S/D) at 5 minutes

  5 minutes

• Umbilical artery velocimetric index - pulsatility index (PI) at 5 minutes

  5 minutes

Study Arms (2)

Ultrasound - patients without hypertensive disorders of pregnancy

EXPERIMENTAL

Ultrasound will be used to measure velocimetric index of the umbilical artery.

Device: Ultrasound

Ultrasound - patients with diagnosed hypertensive disorders of pregnancy

EXPERIMENTAL

Ultrasound will be used to measure velocimetric index of the umbilical artery.

Device: Ultrasound

Interventions

Ultrasound DEVICE

Ultrasound scan of the umbilical artery

Ultrasound - patients with diagnosed hypertensive disorders of pregnancy; Ultrasound - patients without hypertensive disorders of pregnancy

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Samuel Lunenfeld Research Institute, Mount Sinai Hospital: lead

Study Sites (1)

Mount Sinai Hospital

Toronto, Ontario, M5G1X5, Canada

RECRUITING

MeSH Terms

Conditions

Labor Pain; Hypertension

Interventions

Ultrasonography

Condition Hierarchy (Ancestors)

Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis

Study Officials

• Mrinalini Balki, MD

  MOUNT SINAI HOSPITAL

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mrinalini Balki, MD

CONTACT

416-586-4800; mrinalini.balki@uhn.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 17, 2024
• First Posted: October 23, 2024
• Study Start: October 30, 2024
• Primary Completion: January 1, 2026
• Study Completion: January 1, 2026
• Last Updated: July 11, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)