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

NCT ID: NCT06655675

Last Updated: 2025-07-11

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 54 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-10-30
• Study Completion Date: 2026-01-31

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

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Ultrasound - patients without hypertensive disorders of pregnancy

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

Group Type: EXPERIMENTAL

Ultrasound

Intervention Type: DEVICE

Ultrasound scan of the umbilical artery

Ultrasound - patients with diagnosed hypertensive disorders of pregnancy

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

Group Type: EXPERIMENTAL

Ultrasound

Intervention Type: DEVICE

Ultrasound scan of the umbilical artery

Interventions

Ultrasound

Ultrasound scan of the umbilical artery

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

• 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

Samuel Lunenfeld Research Institute, Mount Sinai Hospital

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Mrinalini Balki, MD

Role: PRINCIPAL_INVESTIGATOR

MOUNT SINAI HOSPITAL

Locations

Mount Sinai Hospital

Toronto, Ontario, Canada

Site Status: RECRUITING

Countries

Canada

Central Contacts

Mrinalini Balki, MD

Role: CONTACT

mrinalini.balki@uhn.ca

416-586-4800 ext. 5270

Facility Contacts

Mrinalini Balki, MD

Role: primary

mrinalini.balki@uhn.ca

416-586-4800 ext. 5270

Other Identifiers

24-09

Identifier Type: -

Identifier Source: org_study_id