Clinical trial NCT03504670: Preterm Induction of Labor Timing of Amniotomy: A Randomized Controlled Trial
Official title: Preterm Induction of Labor Timing of Amniotomy: A Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Preterm Pregnancy
Labor Induction
Keywords: Labor induction
Cesarean delivery
Preterm labor induction
Duration of labor induction
Lead sponsor: University of Alabama at Birmingham
Sponsor class: OTHER
First posted: 2018-04-20
Enrollment: 86
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Participants are assigned to early amniotomy (\<4cm cervical dilation) or late amniotomy (≥4cm dilated). Participants may crossover due due to clinical conditions that are not preventable. These conditions may include: unengaged vertex at time of attempted amniotomy, need for internal monitors, or cervical dilation that does not reach 4cm.
Primary purpose: TREATMENT

Brief summary: Artificial rupture of membranes (amniotomy) is a commonly used technique to safely induce and augment labor. It has been shown to reduce the duration of spontaneous and induced labor in term patients (≥37 weeks' gestation). The utility of amniotomy in preterm patients (\<37 weeks' gestation) undergoing medically-indicated induction of labor is unknown. However, it remains a commonly used strategy. We will conduct a trial comparing early amniotomy versus late amniotomy during medically-indicated induction of labor between 23.0 and 35.6 weeks gestation. Women will be randomized to early or late amniotomy after the obstetrician has decided to induce labor for a medical indication. We hypothesize that more women in the early amniotomy group will require cesarean delivery, and the duration of labor will increase in the early amniotomy group.

Detailed description: The rate of preterm birth in the United States is nearly 10%. Up to one-third of these births are the result of a medically-indicated delivery. While induction of labor in women at term gestation has been extensively studied, the same is not true for preterm gestations. Consequently, the same methods of labor induction are used in term and preterm gestations, although preterm gestations may have different responses to induction agents compared to term gestations.

At our institution, a standard induction of labor - for term or preterm women - is performed using a cervical Foley catheter or misoprostol for cervical ripening with the addition of intravenous oxytocin for labor augmentation. As membranes do not typically spontaneously rupture during the induction process, amniotomy is commonly utilized by providers to help augment labor. Amniotomy releases prostaglandin-rich amniotic fluid. These prostaglandins are important mediators of uterine contractility and ultimately active labor. It has been shown to reduce the duration of spontaneous and induced labor in term patients.

The timing of amniotomy is left up to the discretion of the treating providers, as there are no randomized controlled trials to support early versus late amniotomy at preterm gestations. However, a retrospective cohort of nulliparous and multiparous women at our institution undergoing induction at 23-34 weeks, and evaluating early amniotomy at \<4cm cervical dilation versus late amniotomy at ≥4cm dilation, showed an increased risk of cesarean delivery and increased time from start of induction to delivery for early amniotomy, although only the cesarean delivery outcome was significant after adjusting for confounders.

We will conduct an intention-to-treat randomized controlled trial comparing early amniotomy versus late amniotomy during medically-indicated induction of labor between 23.0 and 35.6 weeks gestation. Women will be randomized to early or late amniotomy after the attending obstetrician has decided to induce labor for a medical indication. Early amniotomy will be performed prior to 4cm cervical dilation being reached. Late amniotomy will be performed at greater than or equal to 4cm cervical dilation.

The purpose of this study is to determine whether timing of amniotomy during medically-indicated preterm induction of labor affects labor outcomes. We will specifically be looking at risk of cesarean delivery, duration of labor, maternal morbidity, and neonatal morbidity. We hypothesize that more women in the early amniotomy group will require cesarean delivery and that the duration of labor will increase in the early amniotomy group.

Eligibility criteria: Inclusion Criteria:

* Singleton gestation
* Gestational age at randomization between 23.0 and 35.6 weeks
* Induction of labor planned for maternal or fetal indications
* Reassuring fetal status
* Vertex presentation

Exclusion Criteria:

* Plan for cesarean delivery or contraindication to labor
* Cervix ≥4cm dilated at start of induction
* Signs of spontaneous labor (active contractions with cervical change)
* Ruptured membranes
* Chorioamnionitis
* Intrauterine fetal demise
* Known major fetal anomaly
* Participation in any other clinical trial involving the course of labor
* Maternal hepatitis B, C, or HIV infection (or unknown status)
* Deferring intrapartum fetal monitoring and/or cesarean section for any reason (for example, after periviability counseling)

Primary outcomes:
measure: Cesarean delivery
timeFrame: Duration is dependent upon the length of labor. The maximum time frame would be anticipated to be 120 hours from start of the induction.
Secondary outcomes:
measure: Interval from induction onset to delivery
timeFrame: Duration is dependent upon the length of labor. The maximum time frame would be anticipated to be 120 hours from start of the induction.
measure: Interval from induction onset to vaginal delivery
timeFrame: Duration is dependent upon the length of labor. The maximum time frame would be anticipated to be 120 hours from start of the induction.
measure: Composite maternal morbidity
timeFrame: Measured from start of induction of labor up to 42 days following delivery
measure: Composite neonatal morbidity
timeFrame: Measured up to 28 days of life for the newborn
Other outcomes:
Locations:
city: Birmingham
country: United States
facility: University of Alabama at Birmigham, Women and Infants' Center
state: Alabama
Study officials:
affiliation: University of Alabama at Birmingham
name: Lindsay S Robbins, MD, MPH
role: PRINCIPAL_INVESTIGATOR
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