A Randomized Clinical Trial of Pre-Induction Cervical Ripening by Isosorbide Mononitrate at Term Prgnancy

  • Hana Alani --- Sulaimaniyah University, College of Medicine, Department of Gynecology & Obstetrics
  • Salama Kamel Nasir Sulaimaniyah University, College of Medicine, Department of Gynecology & Obstetrics
  • Sundus Kellow ----- Sulaimaniyah University, College of Medicine, Department of Gynecology & Obstetrics
  • Nasreen Chafor ----- Sulaimaniyah University, College of Medicine, Department of Gynecology & Obstetrics
Keywords: Term pregnancy, Pre-induction cervical ripening, Isosorbide mononitrate.


Background: Induction of labor is deemed successful when it initiates uterine contractions, progressively dilates and effaces the cervix, and leading to the normal vaginal birth of the baby with no maternal or fetal complications . Because the success of induction is related to cervical ripening, artificial cervical ripening before labor induction is used when the cervix is unfavorable to reduce the associated risk of cesarean delivery.

Objective: to test the efficacy and safety of Isosorbide mononitrate for cervical ripening before the induction of labor at term, from.

Patients & methods: A randomized clinical trial was conducted in maternity hospital in Sulaimani, from the 1st of January 2008 to the 1st of July 2008. Forty six pregnant women with gestational age of (37- 42) weeks, singleton, viable, low risk pregnancy and cephalic presentation with Bishop score of less than 6 were selected for induction of labor for various causes. Forty eight hours before induction, 40 mg IMN (2 tablets of 20 mg) were inserted vaginally up to 3 doses 16 hours apart.

Results:It was found that the mean � SD Bishop score before IMN administration was (1.95 � 1.5), while after IMN was (6.65� 3.06) P-value = 0.0001. Sixteen cases (35.6%) went to active labor. The mean � SD time of admission in labor room was (5.06 � 3.8) hours.43 cases (93.5%) needed oxytocin for their inductions & eighteen cases (39.1%) were delivered by C/S. There was no significant change in FHR before and after IMN and all women delivered active babies with normal Apgar score. The main side effect was headache which was experienced by 31cases (63.4%).

Conclusion: IMN is an effective and safe agent for cervical ripening which can be used as an outpatient basis.


Cunningham, Kenneth J. Lveno, Steven L. Induction of labor. William Obstetrics text book., 22nd,2000; 22: 536.

Hofmeyr G. Justus: Induction and augmentation of labor Dewhurst ś Textbook of Obstetrics & Gynecology, Seventh edition, 2007; 23: 2.

Radcliffe J: induction of labor at the start of the new millennium. Reader in Obstetrics & Gynecology University of Oxford 2006 [Medline]

Mervi Väisanen-Tommiska, Ralf Butzow, Olavi Ylikorkala, et al:.Mifepristone- induced nitric oxide release and expression of nitric oxide synthases in the human cervix during early pregnancy. Human-Reproduction; 21: 2007.2180-2184.

Bullarbo M, Norstrom A, Andersch B, et al: Isosorbide Mononitrate induces increase cervical expression of cyclooxygenase-2, but not of cyclooxygenase – 1, at term. European Journal of Obstetric & Gynecology and Reproductive Biology;130: 2007;160-164.

Marie Anne Ledingham, Andrew J. Thamson, Anne Young: Change in the expression of nitric oxide synthase in the human uterine cervix during pregnancy and parturition. Molecular Human Reproduction ; 11(6): 2000;1041-1048.

Leidingham M A, Denison F C, Kelly R W, et al: Nitric oxide donors stimulate prostaglandin F2 alpha and inhibit thromboxane B2 production in human cervix during the first trimester of pregnancy. Mol Hum Repro; 5(10):1999; 973-82.

Mervi Väisänen- Tommiska, M. Nuutila, K- Aittomäki, V. Hiilesmaa and O. Ylikorkala: Nitric oxide metabolites in cervical fluid during pregnancy: Further evidence for the role of cervical nitric oxide in cervical ripening. Am J Obstet Gynecol ; 188: 2003;779-785,

Bennett P.N, Brown M.G. Arterial hypertention, angina pectoris, myocardial infarction Ninth edition; 23: 2005;461.

Inass Osman.MBCHB. Fiona Maekenzie MRCOG, Jane Norrie MSC, et al,. The “PRIM “Study: A randomized comparison of prostaglandin E2 gel with the nitric oxide donor isosorbide mononitrate for cervical ripening before induction of labor at term. American Journal of Obstetrics and Gynecology., 194: 2006;1012-21.

Rameez MF, Goone Wardene : Nitric Oxide donor isosorbide mononitrate for pre- induction cervical ripening at 41 weeks gestation: A randomized controlled trial. J Obstet Gynaecol Res; 33 (4):Aug2007; 452-6.

Thamson AJ, Lunan CB, Ledingham M, et al: Randomized trial of nitric donor versus prostaglandin for cervical ripening before first – trimester termination of pregnancy. Lanet; 352:1998;1083-6 .

Filomena Nunes, Rosalinda Rodrigues, Manuel Meirinho.Randomized comparison between intra-vaginal misoprostoland dinoprostone for cervical ripening and induction of labour. Am J Obstet Gynecol ; vol 181 : 1999;626-629.

Erling Ekerhovd, MD, PhD, and Anders Norstorm, MD, PhD: Vaginal administration of the NO donor IMN for cervical ripening at term: A randomized controlled study. Am J Obstet Gynecol;189:2003;1692-7 .

Gabriel R, Darnaud T, Chalot F, Gonzalez N, Leymarie F, Quereux C. Transvaginal sonography of the uterine cervix prior to labor induction. Ultrasound Obstet Gynecol; 19:2002; 254-7.

Thaler Israel, MD and Hagit Kahana, MD: The effect of a nitric oxide donor on fetal heart rate patterns in patient with hypertention. Obstetrics & Gynecology; 100:2002; 987-991.

How to Cite
---, H., Nasir, S., -----, S., & -----, N. (2018). A Randomized Clinical Trial of Pre-Induction Cervical Ripening by Isosorbide Mononitrate at Term Prgnancy. Zanco Journal of Medical Sciences (Zanco J Med Sci), 14(3), 72 - 77. Retrieved from https://zjms.hmu.edu.krd/index.php/zjms/article/view/479
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