What is the management for preterm labor?

From the Guidelines

Management of preterm labor involves prompt intervention to delay delivery and improve neonatal outcomes, with the goal of prolonging pregnancy for at least 48 hours to allow for corticosteroid administration, as recommended by the American College of Obstetricians and Gynecologists (ACOG) 1. The initial steps in managing preterm labor include:

• Hospitalization
• Assessment of maternal and fetal status
• Identification of underlying causes Tocolytic medications are used to temporarily suppress contractions, allowing time for corticosteroid administration. First-line tocolytics include:
• Nifedipine (10-20mg orally every 4-6 hours)
• Indomethacin (50mg loading dose followed by 25mg every 6 hours for up to 48 hours)
• Magnesium sulfate (4-6g IV loading dose followed by 2g/hour maintenance) Corticosteroids, such as betamethasone (12mg IM, two doses 24 hours apart) or dexamethasone (6mg IM, four doses 12 hours apart), accelerate fetal lung maturity when delivery is anticipated between 24 and 34 weeks 1. Magnesium sulfate should be administered for neuroprotection if delivery is imminent before 32 weeks. Group B streptococcus prophylaxis with antibiotics is indicated when delivery is expected. Continuous fetal monitoring and maternal vital signs assessment are essential throughout treatment. Management should be individualized based on gestational age, maternal conditions, and fetal status, with the goal of prolonging pregnancy when safe while preparing for potential preterm delivery. It is also important to consider the potential risks and benefits of tocolytic therapy, as well as the need for individualized care, as highlighted in the 2016 interim update on periviable birth 1. Additionally, the use of antenatal corticosteroids has been shown to reduce the risks of adverse neonatal complications, and their administration should be considered in individuals at risk for late preterm delivery, as recommended by the Society for Maternal-Fetal Medicine consult series #58 1. In women with skeletal dysplasia, the standard management of preterm labor may need to be modified, taking into account anatomical differences that can increase the risk of general and regional anesthesia during pregnancy and delivery 1. Overall, the management of preterm labor requires a comprehensive and individualized approach, with the goal of improving neonatal outcomes and reducing morbidity and mortality.

From the FDA Drug Label

Continuous administration of magnesium sulfate is an unapproved treatment for preterm labor The safety and efficacy of such use have not been established. The administration of magnesium sulfate outside of its approved indication in pregnant women should be by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities If magnesium sulfate is given for treatment of preterm labor, the woman should be informed that the efficacy and safety of such use have not been established and that use of magnesium sulfate beyond 5 to 7 days may cause fetal abnormalities.

The management of preterm labor may involve the use of magnesium sulfate, but its safety and efficacy for this indication have not been established. Magnesium sulfate should only be used in a hospital setting by trained obstetrical personnel and with caution, as its use beyond 5 to 7 days may cause fetal abnormalities 2 2.

From the Research

Management of Preterm Labor

The management of preterm labor involves the use of tocolytic agents to delay delivery and reduce the risk of adverse neonatal outcomes. The goal of tocolysis is to delay delivery for at least 48 hours to allow for the administration of corticosteroids to induce surfactant production in fetal lungs and to transfer the mother to a tertiary facility if necessary.

Tocolytic Agents

Several tocolytic agents are available, including:

• Beta-mimetics, which decrease the number of women in preterm labor giving birth within 48 hours, but do not reduce adverse neonatal outcomes 3
• Calcium channel blockers, such as nifedipine, which decrease adverse neonatal outcomes by significantly delaying delivery 3, 4
• Atosiban, which has the best maternal and fetal safety profile, but does not seem to reduce neonatal complications 3, 5
• Magnesium sulfate, which is controversial as a tocolytic, but is valuable as a neuroprotective agent and for treatment of eclamptic seizures 3, 6
• Indomethacin, which may be a reasonable first choice for acute tocolysis in gestational ages less than 32 weeks' gestation, but prolonged use should be avoided 3
• Transdermal nitroglycerin, which can reduce neonatal morbidity and mortality by decreasing the risk of birth before 28 weeks' gestation 3

Recommendations

Based on the available evidence, the following recommendations can be made:

• Nifedipine may be a reasonable first choice for tocolysis due to its ease of administration and limited side effects relative to β2-mimetics 3, 4
• Atosiban may be a good option for women with preterm labor due to its favorable maternal and fetal safety profile, but its effectiveness in reducing neonatal complications is unclear 3, 5
• Magnesium sulfate should not be used as a tocolytic agent due to its lack of effectiveness and potential side effects 6
• Tocolytic agents should only be used between 24 and 32 completed weeks of gestation, and their use should be individualized based on the patient's clinical condition and presence of other disease states 6, 7