title: The impact of isosorbide mononitrate on cervical ripening and labor induction in primiparous women with term pregnancy: A double-blind, randomized, controlled trial.
abstract: BACKGROUND
  The most favorable method for cervical ripening is not fully agreed upon by practitioners; however, vaginal administration of isosorbide mononitrate (IMN) is considered a low-risk method of labor induction for pregnant women at full term. Our study was designed to assess the effect of IMN on cervical ripening and labor induction among primiparous women in Iran.
  
  
  METHODS
  A randomized, double-blind, placebo-controlled trial was conducted on 90 primiparous women with Bishop score ≤ 5, term pregnancy, and no sign of labor. The women were allocated into two groups to receive either a 40 mg (2 × 20 mg) IMN tablet vaginally (n = 45) or placebo (n = 45) at 0 and 12 h. If uterine contractions were not present after 24 h, women were sent to the labor section for induction of labor. Bishop score, reason for induction, duration of active, second, and third phase of labor, and mode of delivery were assessed.
  
  
  RESULTS
  There was a significant difference between the IMN group and the controls with respect to the Bishop score (4.92 vs. 4.03, P = 0.0.01), induction to active phase interval (387.6 vs. 520.4 min, P = 0.03), the length of induction (350 vs. 446 min, P = 0.03), and the drug administration to delivery interval (33.9 vs. 36.2 h, P = 0.03). The major side effect of IMN was headache, which responded to analgesia.
  
  
  CONCLUSIONS
  IMN can be an effective alternative drug for cervical ripening and could decrease the labor interval. Further studies are necessary to fully address the benefits of IMN, especially in pregnancies of gestational age greater than 42 weeks.
authors: Department of Midwifery, Nursing and Midwifery School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors: Hamideh
authors: H
authors: Yazdizadeh
authors: Parvin
authors: P
authors: Abedi
authors: Shahnaz
authors: S
authors: Najar
authors: Kambiz Ahmadi
authors: KA
authors: Angali
keywords: Bishop score; Iran; cervical ripening; isosorbide mononitrate; primiparous women
references: J Obstet Gynaecol Res. 2007 Aug;33(4):452-6
references: 17688611
references: Int J Gynaecol Obstet. 2002 Aug;78(2):139-45
references: 12175715
references: Cochrane Database Syst Rev. 2003;(1):CD000941
references: 12535398
references: Mol Hum Reprod. 1999 Oct;5(10):973-82
references: 10508227
references: Am J Obstet Gynecol. 2003 Dec;189(6):1692-7
references: 14710100
references: Hum Reprod. 1998 Feb;13(2):245-8
references: 9557812
references: Arch Gynecol Obstet. 2011 Jul;284(1):25-30
references: 20582425
references: Ann N Y Acad Sci. 1997 Sep 26;828:238-53
references: 9329845
references: Am J Obstet Gynecol. 2001 Apr;184(5):958-64
references: 11303205
references: Mol Hum Reprod. 2000 Apr;6(4):382-9
references: 10729322
references: BJOG. 2009 Aug;116(9):1185-95
references: 19624440
references: Br Med Bull. 2003;67:191-204
references: 14711764
references: Int J Gynaecol Obstet. 2008 Apr;101(1):57-61
references: 18222450
references: BJOG. 2009 Aug;116(9):1196-203
references: 19485990
references: Obstet Gynecol. 2010 Jul;116(1):121-126
references: 20567177
references: Am J Obstet Gynecol. 2007 Jan;196(1):50.e1-5
references: 17240231
references: Cochrane Database Syst Rev. 2010 Oct 06;(10):CD000941
references: 20927722