Preterm Induction of Labor Timing of Amniotomy: A Randomized Controlled Trial

NCT ID: NCT03504670

Last Updated: 2021-04-27

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

86 participants

Study Classification

INTERVENTIONAL

Study Start Date

2018-11-14

Study Completion Date

2021-01-13

Brief Summary

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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

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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.

Conditions

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Preterm Pregnancy Labor Induction

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

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 Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Early amniotomy

Women randomized to early amniotomy will have their membranes ruptured in usual fashion using an amniotomy hook when the cervix is less than 4cm dilated. This will occur after cervical ripening has taken place, with 1) a cervical Foley balloon catheter with or without oxytocin and/or 2) misoprostol. Prior to amniotomy, the obstetric provider will assess whether or not the fetal head is engaged. If the fetal head is not engaged (applied to the cervix), amniotomy will be deferred. The patient will be examined every 2 hours until amniotomy can be safely performed (in keeping with our institutional standard of care to examine women every 2-4 hours in labor).

Group Type EXPERIMENTAL

Early Amniotomy

Intervention Type PROCEDURE

This intervention involves using an amniotomy hook to rupture the membranes during a sterile vaginal exam. This intervention will be performed prior to the cervix being dilated 4cm.

Late amniotomy

Women randomized to late amniotomy will have their membranes ruptured once the cervix reaches at least 4cm dilation. This will occur after cervical ripening has taken place, with 1) a cervical Foley balloon catheter with or without oxytocin and/or 2) misoprostol. If the cervix fails to reach 4cm dilation 12 hours following cervical ripening, amniotomy will be performed.

Group Type EXPERIMENTAL

Late Amniotomy

Intervention Type PROCEDURE

This intervention involves using an amniotomy hook to rupture the membranes during a sterile vaginal exam. This intervention will be performed once the cervix is at least 4cm dilated.

Interventions

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Early Amniotomy

This intervention involves using an amniotomy hook to rupture the membranes during a sterile vaginal exam. This intervention will be performed prior to the cervix being dilated 4cm.

Intervention Type PROCEDURE

Late Amniotomy

This intervention involves using an amniotomy hook to rupture the membranes during a sterile vaginal exam. This intervention will be performed once the cervix is at least 4cm dilated.

Intervention Type PROCEDURE

Eligibility Criteria

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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)
Minimum Eligible Age

18 Years

Eligible Sex

FEMALE

Accepts Healthy Volunteers

No

Sponsors

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University of Alabama at Birmingham

OTHER

Sponsor Role lead

Responsible Party

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Lindsay Speros Robbins, MD, MPH

Instructor-Fellow

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Lindsay S Robbins, MD, MPH

Role: PRINCIPAL_INVESTIGATOR

University of Alabama at Birmingham

Locations

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University of Alabama at Birmigham, Women and Infants' Center

Birmingham, Alabama, United States

Site Status

Countries

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United States

References

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Martin JA, Hamilton BE, Osterman MJ, Driscoll AK, Mathews TJ. Births: Final Data for 2015. Natl Vital Stat Rep. 2017 Jan;66(1):1.

Reference Type BACKGROUND
PMID: 28135188 (View on PubMed)

Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm birth. Lancet. 2008 Jan 5;371(9606):75-84. doi: 10.1016/S0140-6736(08)60074-4.

Reference Type BACKGROUND
PMID: 18177778 (View on PubMed)

Fraser WD, Marcoux S, Moutquin JM, Christen A. Effect of early amniotomy on the risk of dystocia in nulliparous women. The Canadian Early Amniotomy Study Group. N Engl J Med. 1993 Apr 22;328(16):1145-9. doi: 10.1056/NEJM199304223281602.

Reference Type BACKGROUND
PMID: 8257472 (View on PubMed)

Gagnon-Gervais K, Bujold E, Iglesias MH, Duperron L, Masse A, Mayrand MH, Sansregret A, Fraser W, Audibert F. Early versus late amniotomy for labour induction: a randomized controlled trial. J Matern Fetal Neonatal Med. 2012 Nov;25(11):2326-9. doi: 10.3109/14767058.2012.695819. Epub 2012 Jun 13.

Reference Type BACKGROUND
PMID: 22616980 (View on PubMed)

Macones GA, Cahill A, Stamilio DM, Odibo AO. The efficacy of early amniotomy in nulliparous labor induction: a randomized controlled trial. Am J Obstet Gynecol. 2012 Nov;207(5):403.e1-5. doi: 10.1016/j.ajog.2012.08.032. Epub 2012 Aug 24.

Reference Type BACKGROUND
PMID: 22959833 (View on PubMed)

Onah LN, Dim CC, Nwagha UI, Ozumba BC. Effect of early amniotomy on the outcome of spontaneous labour: a randomized controlled trial of pregnant women in Enugu, South-east Nigeria. Afr Health Sci. 2015 Dec;15(4):1097-103. doi: 10.4314/ahs.v15i4.7.

Reference Type BACKGROUND
PMID: 26958009 (View on PubMed)

Battarbee AN, Palatnik A, Peress DA, Grobman WA. Association of Early Amniotomy After Foley Balloon Catheter Ripening and Duration of Nulliparous Labor Induction. Obstet Gynecol. 2016 Sep;128(3):592-597. doi: 10.1097/AOG.0000000000001563.

Reference Type BACKGROUND
PMID: 27500341 (View on PubMed)

Parrish MM, Kuper SG, Jauk VC, Baalbaki SH, Tita AT, Harper LM. Does Early Artificial Rupture of Membranes Speed Labor in Preterm Inductions? Am J Perinatol. 2018 Jul;35(8):716-720. doi: 10.1055/s-0037-1612631. Epub 2017 Dec 14.

Reference Type BACKGROUND
PMID: 29241279 (View on PubMed)

ACOG Practice Bulletin No. 107: Induction of labor. Obstet Gynecol. 2009 Aug;114(2 Pt 1):386-397. doi: 10.1097/AOG.0b013e3181b48ef5. No abstract available.

Reference Type BACKGROUND
PMID: 19623003 (View on PubMed)

Kuper SG, Sievert RA, Steele R, Biggio JR, Tita AT, Harper LM. Maternal and Neonatal Outcomes in Indicated Preterm Births Based on the Intended Mode of Delivery. Obstet Gynecol. 2017 Nov;130(5):1143-1151. doi: 10.1097/AOG.0000000000002320.

Reference Type BACKGROUND
PMID: 29016494 (View on PubMed)

Cooney LG, Bastek JA. The Association between Early Artificial Amniotomy and Chorioamnionitis in Nulliparous Induction of Labor. Int Sch Res Notices. 2014 Dec 16;2014:628452. doi: 10.1155/2014/628452. eCollection 2014.

Reference Type BACKGROUND
PMID: 27379338 (View on PubMed)

Other Identifiers

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UAB_EarlyAROM

Identifier Type: -

Identifier Source: org_study_id

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