Tocolysis: A Review of the Literature

Abstract

Importance Preterm delivery represents an important cause of infant morbidity and mortality. Various tocolytics have been studied with the objective of stopping preterm labor, increasing gestational age at delivery, and preventing complications related to preterm birth. Objective This review aims to summarize the major classes of tocolytics and review the evidence regarding use of each. Evidence Acquisition A PubMed search of the following terms was performed to gather relevant data: “tocolytic,” “preterm labor,” “preterm delivery,” “PPROM,” “magnesium,” “indomethacin,” “nifedipine,” and “betamimetics.” Results The benefits and risks of nonsteroid anti-inflammatory drugs, calcium channel blockers, magnesium, and betamimetics are reviewed. Calcium channel blockers afford superior outcomes in terms of prolonging gestation and decreasing neonatal morbidity and mortality with the fewest adverse effects. Conclusions and Relevance Tocolytics, particularly calcium channel blockers, may provide benefit to pregnant women and their infants. Their use should be tailored to the particular clinical circumstances of the patient and used in conjunction with other management strategies (e.g., administration of corticosteroids for fetal lung maturation or magnesium for neuroprotection and transfer to a tertiary medical center). Further research and professional guidelines are needed on optimal use of these agents. Target Audience Obstetricians and gynecologists, family physicians. Learning Objectives After participating in this activity, the provider should be better able to compare the major classes of tocolytics, including mechanisms of action; distinguish the role tocolytics play in preterm labor and appropriate clinical indication and course; and choose a tocolytic based on evidence regarding the potential benefits and risks.

Evaluation of the Fetal Therapy Evidence in Lower Urinary Tract Obstruction: Would an ERAS Guideline Improve Outcomes?

“…Expert reviews for preterm labor and birth are identified for the evidenced-based counseling/informed consent content [78][79][80][81][82][83].…”

Role of Tocolytics in Preterm

“…The study stated, nifedipine showed to have fewer maternal adverse effects than other analgesics. A recent network analysis and another decision study showed that ca channel blockers would be the best choice antipyretic as far as preterm labour is concerned [15]. It is given orally.…”

Do obstetric units adhere to the evidence-based national guideline? A Germany-wide survey on the current practice of initial tocolysis

“…The prevention of PTB remains a great challenge for obstetricians since no causal therapy has yet been established due to its multifactorial etiology (2). The leading symptom of PTB are spontaneous premature uterine contractions, which can effectively be inhibited by tocolytic agents, thus increasing gestational age at delivery (3). However, there is insufficient evidence, that tocolytics significantly reduce neonatal mortality and morbidity (4)(5)(6)(7)(8)(9)(10)(11).…”

“…However, there is insufficient evidence, that tocolytics significantly reduce neonatal mortality and morbidity (4)(5)(6)(7)(8)(9)(10)(11). The primary objectives of tocolysis are to prolong pregnancy by at least 48 hours to complete fetal lung maturation by application of antenatal corticosteroids (ACS) and to ensure in-utero transfer of the pregnant woman to a perinatal center before 34 weeks of gestation (3,(12)(13)(14). Both are evidence-based measures to improve neonatal mortality and morbidity (11,15).…”

“…Both are evidence-based measures to improve neonatal mortality and morbidity (11,15). Tocolysis is unanimously recommended by current guidelines in patients with spontaneous regular premature contractions (defined as  4 within 20 minutes) in association with cervical shortening and/or dilatation (3)(4)(5), but indications for tocolysis and the preferences of tocolytic drugs differ among national guidelines (16,17). Since 2008 surveys from the United States, Canada, Austria, Australia/New Zealand and France have been performed addressing national practice patterns of tocolysis and revealing considerable differences between evidence-based guideline recommendations and actual clinical practice (18)(19)(20)(21)(22)(23).…”