Vaginal application of the nitric oxide donor isosorbide mononitrate for preinduction cervical ripening: A randomized controlled trial to determine effects on maternal and fetal hemodynamics

• Published in: American journal of obstetrics and gynecology Vol. 184; no. 5; pp. 958 - 964
• Main Authors: Nicoll, Antony E., Mackenzie, Fiona, Greer, Ian A., Norman, Jane E.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Elsevier Inc 01-04-2001; Elsevier
• Subjects: Adolescent; Adult; Apgar Score; Biological and medical sciences; Blood pressure; Blood Pressure - drug effects; Cervical Ripening - drug effects; Drug Administration Routes; Female; fetal blood flow; fetal heart rate; Fetus - drug effects; Fetus - physiology; Genital system. Reproduction; Heart Rate - drug effects; Heart Rate, Fetal - drug effects; Hemodynamics - drug effects; Humans; Infant, Newborn; Isosorbide Dinitrate - administration & dosage; Isosorbide Dinitrate - analogs & derivatives; Isosorbide Dinitrate - pharmacology; Labor, Induced; Medical sciences; nitric oxide; Nitric Oxide Donors - administration & dosage; Nitric Oxide Donors - pharmacology; Pharmacology. Drug treatments; Pregnancy; Umbilical Arteries - drug effects; Vagina; fetal blood flow; nitric oxide; Blood pressure; fetal heart rate; pregnancy; Human; Isosorbide mononitrate; Controlled therapeutic trial; Uterine cervix; Inductor; Induced delivery; Blood flow; Ripening; Heart rate; Chemotherapy; Randomization; Vaginal route; Mother; Nitric oxide; Organic nitrate; Female; Fetus; Influence; Arterial pressure; Hemodynamics
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1067/mob.[phone]

Objective: Our aim was to assess the effects of vaginally administered isosorbide mononitrate (a nitric oxide donor) on maternal and fetal hemodynamics in pregnant women at term. Study Design: We conducted a randomized controlled trial. Women were randomly selected to receive vaginally administered isosorbide mononitrate, 20 mg (n = 13) or 40 mg (n = 11), or to undergo a vaginal examination only (n = 12). Maternal pulse, blood pressure, and fetal heart rate were recorded at baseline and then every 30 minutes until 360 minutes. Umbilical artery resistance index and pulsatility index measurements were performed at 0, 180, and 330 minutes. Results: Maternal pulse rate was greater after the administration of isosorbide mononitrate, 20 or 40 mg, compared with the pulse rate in the vaginal examination–only group (greatest difference in means, 21 beats/min; P <.01). Maternal systolic and diastolic blood pressures were greater in the 20-mg and 40-mg isosorbide mononitrate groups than in the vaginal examination–only group (greatest difference in mean systolic and diastolic blood pressure, 15 and 16 mm Hg, respectively; P <.02 and P <.001, respectively). Fetal heart rate was greater in the 40-mg isosorbide mononitrate group than in either the 20-mg isosorbide mononitrate group or the vaginal examination–only group (difference in mean, 15 beats/min; P <.05). No woman required treatment for maternal or fetal tachycardia or maternal hypotension. Neither dose of isosorbide mononitrate had a significant effect on umbilical artery resistance or pulsatility index. Conclusions: Vaginal administration of 20 or 40 mg isosorbide mononitrate to pregnant women at term has an effect on both maternal and fetal hemodynamics, but this effect is not clinically significant. (Am J Obstet Gynecol 2001;184:958-64.)