Oxytocin and Fetal Heart Rate Changes

Fetal Heart Rate or Rhythm Abnormality Affecting Fetus Clinical Trial

Official title:

A Randomized Controlled Trial Evaluating the Effect of the Oxytocin Infusion Rate on Fetal Heart Rate Changes and Maternal-Fetal Outcomes During the Initiation of Combined Spinal-Epidural Labor Analgesia

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT03232918
• Other study ID #: 201609722
• Status: Recruiting
• Phase: Phase 4
• Start date: February 20, 2019
• Est. completion date: December 31, 2025

Study information

• Verified date: May 2024
• Source: University of Iowa
• Contact: Unyime Ituk
• Phone: 319-356-2633
• Email: unyime-ituk[@]uiowa.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 730
• Est. completion date: December 31, 2025
• Est. primary completion date: December 31, 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Female
• Age group: 18 Years to 55 Years

Eligibility

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

Related Conditions & MeSH terms

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

Intervention

Drug:
• 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

Locations

Country	Name	City	State
United States	University of Iowa Hospitals and Clinics	Iowa City	Iowa
United States	Medical College of Wisconsin	Milwaukee	Wisconsin

Sponsors (1)

Lead Sponsor	Collaborator
Unyime Ituk

Country where clinical trial is conducted

United States, 

References & Publications (5)

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. — View Citation

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. — View Citation

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. — View Citation

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. — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Incidence of non-reassuring fetal heart rate tracings	Fetal heart rate tracings will be examined for 30 minutes before and 60 minutes after the initiation of combined spinal epidural analgesia	1.5 hours
Secondary	Effect of oxytocin dose on duration of 1st and 2nd stage of labor	The effect of the intervention on the duration of labor	24 hours
Secondary	Mode of delivery	The effect of the intervention on the rate of spontaneous vaginal delivery, instrumental vaginal delivery and cesarean delivery	24 hours