The Effect of Intramuscular Administration of Dexamethasone Alone or in Combination with Hyoscine Butylbromide in Shortening the duration of Induced Labor in Primigravidas

Abstract
Background: Induction of labour is common in clinical practice and is usually troublesome in primigravidas. Obesta-tricians are always in search of the best method of induction to ensure the best maternal and fetal outcome.
Aim of Study: To evaluate the effect of Intramuscular (IM) administration of dexamethasone alone or in combined with Hyoscine Butylbromide (HBB) on the duration of labour induction in primigravidas.
Patients and Methods: A randomized controlled study was conducted at the Obstetrics and Gynecology casualty department at Kasr Al-Ainy Hospital (Cairo University, Egypt) in the period from November 2015 to April 2016. 150 primi-gravidas with a singleton living healthy fetus who underwent Induction of Labour (IOL) participated in the study. They were randomly allocated into 3 groups: Group A where 50 women received IM dexamethasone (8mg) 6 hours prior to induction then IM 2ml saline at the onset of the active phase, Group B where 50 women received IM dexamethasone (8mg) 6 hours prior to induction then IM HBB (40mg) at the onset of the active phase and Group C (control) where 50 women received two IM saline injections (2mL) 6 hours prior to induction and at the onset of the active phase. IOL was done using 2.5mIU/min intravenous drip of oxytocin (in 500mL lactated Ringer's solution), increasing the dose by 2.5mIU/ml every 20 minutes until labour started. Amniotomy was done at a cervical dilatation of ³6cm, if spontaneous rupture of the membranes had not spontaneously occurred. All participants were monitored by a partogram and continuous CTG through-out labor.
Results: Both groups A and B showed significant short-ening of the duration of the latent phase (3.4±0.6 and 3.6±0.7 vs 4.5±0.6hrs), the duration of the active phase (3.7±0.7 and 3.7±0.6 vs. 4.8±0.7hrs), the duration of the 2nd stage (21.6± 5.3 and 21.9±7.2 vs. 30.0±5.3 minutes) as well as the duration of the 3rd stage (6.3±1.7 and 7.5±1.9 vs. 10.0±2.8 minutes) respectively when compared to the control group (p-value <0.001 for all). No statistical significant differences were noticed in neonatal Apgar score at 1 and 5 minutes between the three groups.
Conclusions: Intramuscular injection of dexamethasone alone or in addition to hyoscine butylbromide was found to shorten the duration of induced labour in primigravidas, with no observed maternal or neonatal complications.