Effect of Dexamethasone on Labour Induction in Term Pregnancies

Effect of Dexamethasone on Labour Induction in Term Pregnancies

The aim of the study is to assess the effect of dexamethasone on labour induction in term pregnancies.

Primary outcome:

The interval between initiation of induction and beginning of the active phase of labour.

Secondary outcomes:

• Duration of active phase of labour (starting with cervical dilatation of 4-5 cm up to full cervical dilatation).
• Duration of second stage of labour
• Mode of delivery.
• Fetal outcome.

Group A:

Will receive one dose of IM dexamethasone sodium phosphate 8 mg (2 mL).

Group B:

Will receive vaginal misoprostol 25 μg tablets every 6 h, up to 4 tablets, for a maximum duration of 24 h.

Group C:

Will receive one dose of IM dexamethasone sodium phosphate 8mg (2mL) with the first dose of vaginal misoprostol 25 μg tablets that will be given every 6 h, up to 4 tablets, for a maximum duration of 24 h.

• Study type: Randomized Controlled Trial
• Population of study:

Pregnant women above 18 years of age, eligible for induction of labour.

● Study location: Cairo University Obstetrics & Gynecology Hospital (Kasr Al-Ainy)

• Methodology in details:

  • Every subject will be subjected to:

  • Written consent.

  • Complete history to exclude systemic disorders, congenital fetal malformation and contraindications for vaginal delivery.

  • General examination of the patients including pulse, blood pressure and body mass index, [weight (kg)/ height (m2)] (20-25) normal weight, (25-30) overweight, (30-35) obese, (35-40) very obese and >40 morbid obese.

  • Abdominal examination including presentation, station of fetal head, fetal heart rate, uterine contractions and exclusion of multiple pregnancies.

  • Local examination to determine cervical dilatation at the beginning of intervention, presenting part, station of fetal head, pelvic adequacy and Bishop scoring.

  • Sonographic examination including assessment of fetal well-being by biophysical profile.

  • Patients will be randomly assigned to three groups using simple randomization via computer-generated random numbers will be used.

  • The women will be divided into three groups:

    1. Group A: They will receive one dose of IM dexamethasone sodium phosphate 8 mg (2 mL).
    2. Group B: They will receive vaginal misoprostol 25 μg tablets every 6 h, up to 4 tablets, for a maximum duration of 24 h.
    3. Group C: They will receive one dose of IM dexamethasone sodium phosphate 8mg (2mL) with the first dose of vaginal misoprostol 25 μg tablets that will be given every 6 h, up to 4 tablets, for a maximum duration of 24 h.

• Regarding group A,B and C the investigators will wait 24hrs after the last dose, then reassessment by senior obstetrician will be done and if induction is unsuccessful it'll be determined whether the patient is for either CS or second 24hr attempt at induction by misoprostol.

• Primary outcome:

The interval between initiation of induction and beginning of the active phase of labour.

• Secondary outcomes:

  • Duration of active phase of labour (starting with cervical dilatation of 4-5 cm up to full cervical dilatation).
  • Duration of second stage of labour
  • Mode of delivery.
  • Fetal outcome.

• Sample size Assuming that the mean interval between the start of induction and the beginning of the active phase among cases 2.87±1.57 hours versus 3.8±1.72 hours among controls, so a minimum sample of 150 patients, divided into three equal groups (50 patients each), will achieve 80% power at 0.05 significance level. Sample size calculated using OpenEpi, Version 3, open source calculator-(SSMean).

Inclusion Criteria:

• Age > 18 years.
• Nulliparous.
• Vertex presentation.
• Singleton pregnancy.
• Gestational age ≥ 39 weeks according to a reliable date for the last menstrual period or a first-trimester ultrasound evaluation.
• No contraindication for vaginal delivery.

Exclusion Criteria:

• Indication for cesarean section e. g. Placenta previa, intrauterine growth retardation, non-vertex presentation and previous cesarean section.
• Maternal medical disorders as diabetes mellitus and severe pre-eclampsia.
• Preterm labour and preterm rupture of membranes.
• Gestational age <39 weeks of gestation.
• Fetal macrosomia > 4kg (estimated by u/s).