title: Progestogens for preterm birth prevention: a systematic review and meta-analysis.
abstract: OBJECTIVE
  We systematically reviewed the effectiveness of progestogens for prevention of preterm birth among women with prior spontaneous preterm birth, multiple gestations, preterm labor, short cervix, or other indications.
  
  
  METHODS
  We searched MEDLINE and EMBASE databases for English language articles published from January 1966 to October 2011.
  
  
  METHODS
  We excluded publications that were not randomized controlled trials or had fewer than 20 participants, identifying 34 publications, of which 19 contained data for Bayesian meta-analysis.
  
  
  RESULTS
  Two reviewers independently extracted data and assigned overall quality ratings based on predetermined criteria. Among women with prior preterm birth and a singleton pregnancy (five randomized controlled trials), progestogen treatment decreased the median risk of preterm birth by 22% (relative risk [RR] 0.78, 95% Bayesian credible interval 0.68-0.88) and neonatal death by 42% (RR 0.58, 95% Bayesian credible interval 0.27-0.98). The evidence suggests progestogen treatment does not prevent prematurity (RR 1.02, 95% Bayesian credible interval 0.87-1.17) or neonatal death (RR 1.44, 95% Bayesian credible interval 0.46-3.18) in multiple gestations. Limited evidence suggests progestogen treatment may prevent prematurity in women with preterm labor (RR 0.62, 95% Bayesian credible interval 0.47-0.79) and short cervix (RR 0.52, 95% Bayesian credible interval 0.36-0.70). Across indications, evidence about maternal, fetal, or neonatal health outcomes, other than reducing preterm birth and neonatal mortality, is inconsistent, insufficient, or absent.
  
  
  CONCLUSIONS
  Progestogens prevent preterm birth when used in singleton pregnancies for women with a prior preterm birth. In contrast, evidence suggests lack of effectiveness for multiple gestations. Evidence supporting all other uses is insufficient to guide clinical care. Overall, clinicians and patients lack longer-term information to understand whether intervention has the ultimately desired outcome of preventing morbidity and promoting normal childhood development.
authors.affiliation: Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, and the Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37203-1738, USA. frances.likis@vanderbilt.edu
authors.forename: Frances E
authors.initials: FE
authors.lastname: Likis
authors.forename: Digna R Velez
authors.initials: DR
authors.lastname: Edwards
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Andrews
authors.forename: Alison L
authors.initials: AL
authors.lastname: Woodworth
authors.forename: Rebecca N
authors.initials: RN
authors.lastname: Jerome
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Fonnesbeck
authors.forename: J Nikki
authors.initials: JN
authors.lastname: McKoy
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Hartmann
mesh_terms: D001499:Bayes Theorem; D005260:Female; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology / Q000517:prevention & control*; D011372:Progestins / Q000627:therapeutic use*; D012008:Recurrence; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D011372:Progestins