Oxytocin and Fetal Heart Rate Changes

NCT ID: NCT03232918

Last Updated: 2025-06-04

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: PHASE4
• Total Enrollment: 730 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-02-20
• Study Completion Date: 2025-12-31

Brief Summary

The reported risk of nonreassuring fetal heart trace following neuraxial analgesia is 3-23%. This variability may be due to fluid and oxytocin management prior to and during the initiation of neuraxial analgesia. The study hypothesis is that decreasing the oxytocin infusion rate by 50 % prior to initiation of combined spinal epidural analgesia will cause a reduction in the incidence of adverse fetal heart rate changes.

Detailed Description

Oxytocin is used in labor and delivery to increase the frequency of contractions and augment uterine contractile strength, thereby establishing a regular pattern of labor. However, the administration of exogenous oxytocin in the presence of an uncoordinated labor pattern confers a risk for an increase in uterine contraction frequency, resulting in inadequate relaxation periods. This leads to an increase in the basal tone of the uterus, which may lead to a tetanic contraction with the risk of decreased uteroplacental blood flow and fetal hypoxemia. Previous studies investigating low- versus high-dose oxytocin for induction or augmentation of labor have had conflicting results on the effect on fetal heart rate abnormalities. One of the limitations of these studies is that the labor analgesia was not standardized. The combination of low-dose combined spinal epidural analgesia and the high/low dose oxytocin have not been evaluated. One of the proposed mechanisms for nonreassuring fetal heart a tracing after initiation of analgesia is that the pain relief from neuraxial analgesia causes a decrease in catecholamine release by the sympathetic nervous system. The subsequent decrease in the circulating epinephrine concentration contributes to an increase in uterine tone, as epinephrine is a potent tocolytic agent. The increased tone, in turn, leads to a decrease in placental blood flow, and eventually fetal bradycardia. The primary outcome of this study is the incidence of non-reassuring fetal heart rate tracings within the first 60 minutes after the placement of combined spinal epidural analgesia

Conditions

Fetal Bradycardia Complicating Labor and Delivery; Fetal Bradycardia During Labor; Fetal Heart Rate or Rhythm Abnormality Affecting Fetus

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Standard Dose Oxytocin

Patients randomized to the standard dose oxytocin will have their oxytocin infusion maintained at the standard of care protocol prior to placement of a combined spinal epidural for labor analgesia

Group Type: NO_INTERVENTION

No interventions assigned to this group

Half Dose Oxytocin

Patients randomized to the half dose oxytocin will have their oxytocin infusion reduced by 50 % prior to placement of a combined spinal epidural for labor analgesia.

Group Type: EXPERIMENTAL

Half dose Oxytocin

Intervention Type: DRUG

Patients randomized to the half dose oxytocin group will have the oxytocin infusion reduced to 50 % prior to placement of combined spinal epidural for labor analgesia

Interventions

Half dose Oxytocin

Patients randomized to the half dose oxytocin group will have the oxytocin infusion reduced to 50 % prior to placement of combined spinal epidural for labor analgesia

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• Healthy nulliparous or multiparous women at term (37 > weeks' gestation)
• Singleton pregnancy
• Request for neuraxial analgesia
• Oxytocin used for induction of labor or augmentation of labor per institutional protocols

Exclusion Criteria

• Use of chronic analgesic medications
• Prior administration of systemic opioid labor analgesia
• Non-vertex presentation
• Contraindication to neuraxial analgesia
• Category 3 fetal heart rate tracing prior to the initiation of combined spinal epidural analgesia

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 55 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

Unyime Ituk

OTHER

Sponsor Role: lead

Responsible Party

Unyime Ituk

Associate Professor

Responsibility Role: SPONSOR_INVESTIGATOR

Principal Investigators

Unyime Ituk

Role: STUDY_DIRECTOR

University of Iowa

Locations

University of Iowa Hospitals and Clinics

Iowa City, Iowa, United States

Site Status: RECRUITING

Medical College of Wisconsin

Milwaukee, Wisconsin, United States

Site Status: NOT_YET_RECRUITING

Countries

United States

Central Contacts

Unyime Ituk

Role: CONTACT

unyime-ituk@uiowa.edu

319-356-2633

Facility Contacts

Unyime Ituk, MD

Role: primary

unyime-ituk@uiowa.edu

319-356-2633

Zita A Sibenaller, PhD

Role: backup

zita-sibenaller@uiowa.edu

319-356-8878

Meredith Albrecht, MD

Role: primary

maaalbrecht@mcw.edu

References

Mardirosoff C, Dumont L, Boulvain M, Tramer MR. Fetal bradycardia due to intrathecal opioids for labour analgesia: a systematic review. BJOG. 2002 Mar;109(3):274-81. doi: 10.1111/j.1471-0528.2002.01380.x.

Reference Type: BACKGROUND

PMID: 11950182 (View on PubMed)

Abrao KC, Francisco RPV, Miyadahira S, Cicarelli DD, Zugaib M. Elevation of uterine basal tone and fetal heart rate abnormalities after labor analgesia: a randomized controlled trial. Obstet Gynecol. 2009 Jan;113(1):41-47. doi: 10.1097/AOG.0b013e31818f5eb6.

Reference Type: BACKGROUND

PMID: 19104358 (View on PubMed)

Clarke VT, Smiley RM, Finster M. Uterine hyperactivity after intrathecal injection of fentanyl for analgesia during labor: a cause of fetal bradycardia? Anesthesiology. 1994 Oct;81(4):1083. doi: 10.1097/00000542-199410000-00041. No abstract available.

Reference Type: BACKGROUND

PMID: 7943823 (View on PubMed)

Satin AJ, Leveno KJ, Sherman ML, Brewster DS, Cunningham FG. High- versus low-dose oxytocin for labor stimulation. Obstet Gynecol. 1992 Jul;80(1):111-6.

Reference Type: BACKGROUND

PMID: 1603479 (View on PubMed)

Budden A, Chen LJ, Henry A. High-dose versus low-dose oxytocin infusion regimens for induction of labour at term. Cochrane Database Syst Rev. 2014 Oct 9;2014(10):CD009701. doi: 10.1002/14651858.CD009701.pub2.

Reference Type: BACKGROUND

PMID: 25300173 (View on PubMed)

Other Identifiers

201609722

Identifier Type: -

Identifier Source: org_study_id