Protocols for High-Risk Pregnancies Snapshot

December 15, 2015

The key messages of Protocol 42: Preterm Labor.

Protocols for High-Risk Pregnancies: An Evidence-Based Approach, 6th Edition

Snapshot: Protocol 42: Preterm Labor

Author: Vincenzo Berghella, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Thomas Jefferson University, Philadelphia, PA


In this protocol, Dr Berghella reviews the pathophysiology, diagnosis, prevention, and treatment of preterm labor. Included are a proposed algorithm for use of cervical length and fetal fibronectin to screen women with symptoms of threatened preterm labor, a table of suggested prevention strategies, and a reading list.

The incidence of preterm birth in the United States has decreased in recent years, yet it remains one of the highest in the world. Every year, more than a half million babies are born preterm in this country and prematurity is the foremost problem in obstetrics. Measurement of cervical length on transvaginal ultrasound and fetal fibronectin are the 2 tests with the best data for predicting which women with preterm labor are likely to deliver preterm. As Dr Berghella notes, prevention of preterm labor is better than treatment.

Key Messages:

·       Treatment of preterm labor should be reserved for women at real risk of preterm birth. Most women with a cervical length <20 mm on transvaginal ultrasound or a measurement of 20 to 30 mm and a positive fetal fibronectin test will deliver preterm.

·       Strategies to consider for optimizing fetal status in women with true preterm labor are transfer to an appropriate hospital and administration of antenatal corticosteroids.

·       Nifedipine and indomethacin are the primary tocolytics for clinical use. Evidence does not support use of tocolysis once antenatal corticosteroids have been administered.

·       If use of magnesium sulfate is a consideration, administration should be done in accordance with protocols from one of the larger trials that assessed use of the drug for fetal neuroprotection.

·       Data are insufficient to support use of bed rest, progesterone therapy, or antibiotics for prevention of preterm birth in women with preterm labor. No interventions have been proven to prevent preterm birth between discharge following an episode of preterm labor and eventual delivery.


READ the complete protocol on Preterm Labor from Protocols for High-Risk Pregnancies: An Evidence-Based Approach, 6th Edition, edited by John T. Queenan, Catherine Y. Spong, and Charles J. Lockwood, now at


BUY the book (