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Oxytocin and Fetal Heart Rate Changes

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

Status
Recruiting
Phases
Phase 4
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03232918
Enrollment
730
Registered
2017-07-28
Start date
2019-02-20
Completion date
2025-12-31
Last updated
2025-06-04

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

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

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

Interventions

DRUGHalf 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

Sponsors

Unyime Ituk
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)

Masking description

The labor room nurse will be aware of the patient group assignment and will adjust the dose of the drug based on group assignment. The Investigator, Physician Provider and Outcome Assessor will be blinded.

Eligibility

Sex/Gender
FEMALE
Age
18 Years to 55 Years
Healthy volunteers
Yes

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

Design outcomes

Primary

MeasureTime frameDescription
Incidence of non-reassuring fetal heart rate tracings1.5 hoursFetal heart rate tracings will be examined for 30 minutes before and 60 minutes after the initiation of combined spinal epidural analgesia

Secondary

MeasureTime frameDescription
Effect of oxytocin dose on duration of 1st and 2nd stage of labor24 hoursThe effect of the intervention on the duration of labor
Mode of delivery24 hoursThe effect of the intervention on the rate of spontaneous vaginal delivery, instrumental vaginal delivery and cesarean delivery

Countries

United States

Contacts

Primary ContactUnyime Ituk
unyime-ituk@uiowa.edu319-356-2633

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026