What is the recommended dosage and usage of Dinoprostone (prostaglandin E2) for labor induction in pregnant women at or near term?

Dinoprostone for Labor Induction: Dosing and Administration

For cervical ripening and labor induction at term, dinoprostone gel (0.5 mg) should be administered intracervically with repeat dosing every 6 hours as needed (maximum 1.5 mg/24 hours), or alternatively, a 10 mg vaginal insert can be placed for up to 24 hours, though misoprostol is now preferred due to lower cost, better efficacy, and fewer cardiovascular risks. 1, 2

Standard Dosing Protocols

Dinoprostone Gel (Prepidil)

• Initial dose: 0.5 mg intracervically, administered just below the internal os 1
• Repeat dosing: May repeat 0.5 mg every 6 hours based on cervical/uterine response 1
• Maximum cumulative dose: 1.5 mg (7.5 mL gel) per 24-hour period 1
• Catheter selection: Use 20 mm catheter if no effacement present; use 10 mm catheter if cervix is 50% effaced 1
• Post-administration positioning: Patient should remain supine for 15-30 minutes to minimize leakage 1

Dinoprostone Vaginal Insert (Cervidil/Propess)

• Dose: Single 10 mg controlled-release pessary 3
• Duration: Can remain in place for up to 24 hours, though most guidelines originally recommended 12 hours 4
• Removal: Should be removed at onset of active labor or if complications occur 3
• Safety data: 24-hour use appears as safe as 12-hour use, with most tachysystole events (68%) occurring within the first 12 hours 4

Monitoring Requirements

• With vaginal insert: Continuous fetal heart rate and uterine activity monitoring from insertion until at least 15 minutes after removal 5
• With gel: Continuous monitoring from 30 minutes to 2 hours after each administration 5

Interval Before Oxytocin

• Recommended waiting period: 6-12 hours after dinoprostone gel administration before starting intravenous oxytocin 1

Critical Contraindications

Absolute Contraindications

• Active cardiovascular disease: Dinoprostone is absolutely contraindicated due to profound blood pressure effects, theoretical risk of coronary vasospasm, and risk of arrhythmias 2
• Severe cardiac conditions: Including severe aortic stenosis, pulmonary hypertension, or cyanotic heart disease 2
• Previous cesarean delivery: While this applies more strictly to misoprostol, caution is warranted with all prostaglandins 5, 6

Preferred Alternatives in High-Risk Patients

• Cardiac disease patients: Mechanical methods such as Foley catheter are preferable to dinoprostone, especially in cyanotic heart disease where drops in systemic vascular resistance would be detrimental 2

Comparative Effectiveness: Dinoprostone vs. Misoprostol

Why Misoprostol is Often Preferred

• Cost difference: Misoprostol costs $0.36-$1.20 per tablet versus $65-$75 for dinoprostone gel or $165 for dinoprostone insert 5
• Storage: Misoprostol is stable at room temperature; dinoprostone requires refrigeration 5, 2
• Cesarean rates: Oral misoprostol results in fewer cesarean sections compared to vaginal dinoprostone (RR 0.84) 7, 2
• Efficacy: Lower doses of misoprostol (25 µg every 3-6 hours) are effective for cervical ripening and labor induction 5, 6

When Dinoprostone May Still Be Used

• Controlled release benefit: The vaginal insert provides constant, sustained release with easy retrievability in case of complications 3
• Proven safety profile: Demonstrated effectiveness in low-risk pregnancies with 67.6% vaginal delivery rate 8
• Reversible hyperstimulation: Uterine hyperstimulation is rapidly reversible upon removal of the insert 3

Common Pitfalls and Cautions

Repeat Dosing Concerns

• Second dinoprostone pessary NOT recommended: Recent evidence shows no superiority of a second dinoprostone pessary over oxytocin when the first pessary fails, with significantly more cervical ripening failure (57.1% vs 19%) and longer time to delivery 9
• If first pessary fails: Proceed directly to oxytocin rather than placing a second dinoprostone insert 9

Tachysystole Risk

• Incidence: Occurs in approximately 9.3% of patients, with mean time to onset of 10 hours 4
• Management advantage: The retrievable insert allows immediate removal if hyperstimulation occurs 3

Nulliparous vs. Multiparous Outcomes

• Cesarean risk: 3.8 times higher in nulliparous women compared to multiparous women 8
• Time considerations: Risk of cesarean section increases if time from induction to active labor exceeds 12.5 hours 8

Handling and Administration Technique

• Skin contact precaution: Use caution to prevent skin contact; wash hands thoroughly with soap and water after administration 1
• Temperature: Bring gel to room temperature (59-86°F) before use; do not force warming with water bath or microwave 1
• Sterile technique: Visualize cervix with speculum and use sterile technique for administration 1
• Catheter filling: Expel air from catheter before administration by pushing plunger assembly 1
• Single-use only: Contents of one syringe for one patient only; discard unused portions 1