title: The safety of progestogen in the prevention of preterm birth: meta-analysis of neonatal mortality.
abstract: BACKGROUND
  The safety of preventive progestogen therapy for preterm birth remains to be established. This meta-analysis aimed to evaluate the effects of preventive progestogen therapy on neonatal mortality.
  
  
  METHODS
  Randomized controlled trials (RCTs) on the preventive use of progestogen therapy, published between October 1971 and November 2015, were identified by searching MEDLINE/PubMed, EMBASE, Scopus, ClinicalTrials.gov, Cochrane Library databases, CINAHL, POPLINE, and LILACS using "progesterone" and "preterm birth" as key terms. We conducted separate analyses according to the type of progestogen administered and plurality of the pregnancy.
  
  
  RESULTS
  Twenty-two RCTs provided data on 11,188 neonates. Preventive progestogen treatment in women with a history of preterm birth or short cervical length was not associated with increased risk of neonatal death compared to placebo in all analyzed progestogen types and pregnancy conditions. The pooled relative risks (95% confidence interval) of neonatal mortality were 0.69 (0.31-1.54) for vaginal progestogen in singleton pregnancies, 0.6 (0.33-1.09) for intramuscular progestogen in singleton pregnancies, 0.96 (0.51-1.8) for vaginal progestogen in multiple pregnancies, and 0.96 (0.49-1.9) for intramuscular progestogen in multiple pregnancies.
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that administration of preventive progestogen treatment to women at risk for preterm birth does not appear to negatively affect neonatal mortality in single or multiple pregnancies regardless of the route of administration.
authors.forename: Ki Hoon
authors.initials: KH
authors.lastname: Ahn
authors.forename: Na-Young
authors.initials: NY
authors.lastname: Bae
authors.forename: Soon-Cheol
authors.initials: SC
authors.lastname: Hong
authors.forename: Ji-Sung
authors.initials: JS
authors.lastname: Lee
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Lee
authors.forename: Hee-Jung
authors.initials: HJ
authors.lastname: Jee
authors.forename: Geum-Joon
authors.initials: GJ
authors.lastname: Cho
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Oh
authors.forename: Hai-Joong
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000077713:17 alpha-Hydroxyprogesterone Caproate; D000282:Administration, Intravaginal; D005260:Female; D006801:Humans; D006908:Hydroxyprogesterones / Q000008:administration & dosage; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007273:Injections, Intramuscular; D011247:Pregnancy; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000517:prevention & control*; D011374:Progesterone / Q000008:administration & dosage; D011372:Progestins / Q000627:therapeutic use*
chemical_list: D006908:Hydroxyprogesterones; D011372:Progestins; D000077713:17 alpha-Hydroxyprogesterone Caproate; D011374:Progesterone