title: Progesterone for prevention of recurrent preterm birth: impact of gestational age at previous delivery.
abstract: OBJECTIVE
  Preterm birth occurs in 1 of 8 pregnancies and may result in significant morbidity and mortality. 17-alpha hydroxyprogesterone caproate (17-OHP caproate) has been found to be efficacious in reducing the risk of subsequent preterm delivery in women who have had a previous spontaneous preterm birth (sPTB). This analysis was undertaken to evaluate if 17-OHP caproate therapy works preferentially depending on the gestational age at previous spontaneous delivery. We hypothesized that treatment with 17-OHP caproate is more effective in prolonging pregnancy depending on the gestational age of the earliest previous preterm birth (20-27.9, 28-33.9 vs 34-36.9 weeks).
  
  
  METHODS
  This was a secondary analysis of 459 women with a previous sPTB enrolled in a randomized controlled trial evaluating 17-OHP caproate versus placebo. Effectiveness of 17-OHP caproate for pregnancy prolongation was evaluated based on gestational age at earliest previous delivery according to clinically relevant groupings (20-27.9, 28-33.9, and 34-36.9 weeks). Statistical analysis included the chi-square, Fisher exact, and Kruskal-Wallis tests, logistic regression, and survival analysis using proportional hazards.
  
  
  RESULTS
  Gestational age at earliest previous delivery was similar between women treated with 17-OHP caproate or placebo (P = .1). Women with earliest delivery at 20 to 27.9 weeks and at 28 to 33.9 weeks delivered at significantly more advanced gestational age if treated with 17-OHP caproate than with placebo (median 37.3 vs 35.4 weeks, P = .046 and 38.0 vs 36.7 weeks, P = .004, respectively) and were less likely to deliver <37 weeks (42% vs 63%, P = .026 and 34% vs 56%, P = .005, respectively). Those with earliest delivery at 34 to 36.9 weeks were not significantly different between 17-OHP caproate or control.
  
  
  CONCLUSIONS
  17-OHP caproate therapy given to prevent recurrent PTB is associated with a prolongation of pregnancy overall, and especially for women with a previous spontaneous PTB at <34 weeks.
authors.affiliation: National Institute of Child Health and Human Development, Bethesda, MD, USA.
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Spong
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Meis
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Thom
authors.forename: Baha
authors.initials: B
authors.lastname: Sibai
authors.forename: Mitchell P
authors.initials: MP
authors.lastname: Dombrowski
authors.forename: Atef H
authors.initials: AH
authors.lastname: Moawad
authors.forename: John C
authors.initials: JC
authors.lastname: Hauth
authors.forename: Jay D
authors.initials: JD
authors.lastname: Iams
authors.forename: Michael W
authors.initials: MW
authors.lastname: Varner
authors.forename: Steve N
authors.initials: SN
authors.lastname: Caritis
authors.forename: Mary J
authors.initials: MJ
authors.lastname: O'Sullivan
authors.forename: Menachem
authors.initials: M
authors.lastname: Miodovnik
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Leveno
authors.forename: Deborah
authors.initials: D
authors.lastname: Conway
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Wapner
authors.forename: Marshall
authors.initials: M
authors.lastname: Carpenter
authors.forename: Brian
authors.initials: B
authors.lastname: Mercer
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
authors.forename: John M
authors.initials: JM
authors.lastname: Thorp
authors.forename: Alan M
authors.initials: AM
authors.lastname: Peaceman
authors.forename: Steven
authors.initials: S
authors.lastname: Gabbe
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000627:therapeutic use*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D016016:Proportional Hazards Models; D012008:Recurrence
chemical_list: D019326:17-alpha-Hydroxyprogesterone