Time of Oxytocin Initiation at 2nd Stage of Labor and Adverse Outcomes

Study Overview
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Brief Summary
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Early oxytocin administration at the 2nd stage of labor is associated with a higher rate of vaginal delivery, shorter second stage duration, and fewer adverse maternal and neonatal outcomes.

Detailed Description
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Cesarean delivery (CD) is one of the most common surgeries performed worldwide. In the last few decades, its rate has steadily increased worldwide, leading to an increase in maternal morbidity and mortality compared to vaginal delivery (VD)1. In 2014, the American College of Obstetricians and Gynecologists (ACOG) and Society for Maternal Fetal Medicine (SMFM) published an Obstetric Care Consensus for safe prevention of primary cesarean delivery, allowing an additional hour of pushing during the 2nd stage of labor for both nulliparous and multiparous women before diagnosing prolonged 2nd of labor2-4. Prolonged 2nd stage is especially common among nulliparous women5, and is defined as more than three hours of pushing6, or four hours for women with a regional anesthesia. Prolonged 2nd stage has been shown to be associated with maternal adverse outcomes, such as assisted-vaginal delivery, CD, and postpartum hemorrhage (PPH)7,8, and neonatal adverse outcomes such as low 5-minute Apgar score, and NICU admissions9. Oxytocin is the primary and the most widely used pharmacological agent for induction and augmentation of labor10. Administrating oxytocin during labor is a common practice and is used to intensify contractions and decrease the chances of a non-progressive labor and associated adverse outcomes11,12. Despite its extensive use, there are several protocols which varies between different countries and obstetric wards. Likewise, there is no consensus regarding the duration or dosage of oxytocin infusion during labor, and especially during the 2nd stage of labor13. The study will assess the optimal time initiation of Oxytocin during the 2nd stage of labor, and its association to mode of delivery, and adverse maternal and neonatal outcomes.

Official Title
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Association Between Time of Oxytocin Initiation at 2nd Stage of Labor and Adverse Outcomes

Conditions
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Delivery Complication, Cesarean Delivery Affecting Fetus

Intervention / Treatment
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* Drug: Oxytocin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Singleton pregnancy Maternal age ≥ 18 years' old Oxytocin administration initiated or renewed during second stage of labor Exclusion Criteria: Maternal age < 18 years' old Multiple gestation pregnancy Known fetal malformations Uterine scar

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: A randomized controlled trial of singleton gestations receiving oxytocin during the second stage of labor at a single tertiary medical center. Women will be randomly allocated to one of two groups - immediate initiation of oxytocin at full dilation versus delayed oxytocin initiation following one hour of full dilation.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Immediate oxytocin<br>This arm will receive oxytocin when entering 2nd stage (full dilation) | Drug: Oxytocin<br>* Native oxytocin analog<br>* Other names: Pitocin;|
| Other: Delayed oxytocin<br>This arm will receive oxytocin one hour after entering 2nd stage (full dilation) | Drug: Oxytocin<br>* Native oxytocin analog<br>* Other names: Pitocin;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mode of delivery | Vaginal or instrumental or cesarean | Delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 2nd stage duration | Minutes | Delivery | 
| intrapartum fever | Rate of chorioamnionitis | Delivery or 48 hours postpartum | 
| Meconium stain | Rate | Delivery | 
| Postpartum hemorrhage | more than 500 ml following vaginal delivery or more than 1000 ml at cesarean delivery | Delivery | 
| FHR decelerations | Variable or Late Decelerations viewed by the physician according to external fetal monitor. | Delivery | 
| Neonatal pH | Umbilical cord pH | Delivery | 
| Neonatal Apgar score | 5 minutues Apgar score | Delivery | 
| Admission of the neonate to neonatal intensive care unit | Admission of the neonate to neonatal intensive care unit | Immediate postpartum, up to 5 days. |