How is cervical dilatation performed, particularly using dinoprostone (prostaglandin E2) gel?

Cervical Dilatation Using Dinoprostone Gel

Dinoprostone (prostaglandin E2) for cervical ripening is administered as a 10 mg vaginal insert placed in the posterior vaginal fornix, left in place for up to 12 hours, and must be removed at the onset of active labor or at least 30 minutes before oxytocin administration. 1

Administration Technique for Dinoprostone Vaginal Insert

Pre-insertion Preparation

• Keep the insert frozen until immediately before use—do not warm it prior to insertion 1
• Open the foil package by tearing along the marked line; never use scissors or sharp objects as this may damage the retrieval system 1
• Verify the retrieval system is intact before proceeding—do not use if damaged 1

Insertion Procedure

• Place the insert transversely in the posterior fornix of the vagina 1
• Use minimal water-miscible lubricant if needed to assist insertion, but avoid excess coating as this prevents proper drug release 1
• Tuck excess retrieval system into the vagina to prevent displacement, but leave a small portion outside for easy removal 1
• The patient must remain recumbent for 2 hours after insertion; ambulation is permitted afterward if the insert remains properly positioned 1
• Sterile conditions are not required for insertion 1

Dosing and Duration

• One 10 mg insert releases approximately 0.3 mg of dinoprostone per hour for up to 12 hours 1
• This is a single-dose application—do not use multiple inserts simultaneously 1

Monitoring Requirements During Use

Continuously monitor the following throughout the 12-hour period: 1

• Uterine contractile activity (frequency, duration, intensity)
• Fetal heart rate patterns
• Progression of cervical dilatation and effacement

Removal Criteria

Remove the insert immediately if any of the following occur: 1

• Onset of active labor (typically ≥6 cm dilatation with regular contractions)
• After 12 hours of use (maximum duration)
• Prior to amniotomy
• Uterine tachysystole (>6 contractions per 10 minutes for two consecutive 10-minute periods)
• Uterine hyperstimulation or hypertonicity
• Fetal distress or abnormal fetal heart rate patterns

Removal Technique

• Locate the retrieval system and pull gently until the entire insert is removed 1
• Perform visual inspection to confirm complete removal—the slab will continue releasing drug if any portion remains 1

Critical Timing Considerations

• Wait at least 30 minutes after removing dinoprostone before administering oxytocin 1
• Never use dinoprostone concurrently with intravenous oxytocic agents 1

Alternative Prostaglandin Formulations

While the vaginal insert is the focus, dinoprostone gel (0.5 mg intracervically) can be administered every 6 hours for up to three doses as an alternative formulation 2, 3. However, the controlled-release vaginal insert offers advantages of single application with sustained drug delivery 4.

Safety Profile and Common Pitfalls

Uterine hyperstimulation is the primary concern with dinoprostone use, occurring in 11.9-18.4% of cases 2, 3. The advantage of the vaginal insert is that hyperstimulation is rapidly reversible upon removal 4.

Common errors to avoid:

• Warming the insert before use (reduces efficacy) 1
• Using excessive lubricant (prevents drug release) 1
• Failing to verify complete removal (continued drug delivery) 1
• Administering oxytocin too soon after removal (increased hyperstimulation risk) 1
• Using in patients with previous cesarean section or uterine surgery (contraindicated due to rupture risk) 1

Contraindications

Do not use dinoprostone if: 1

• Evidence of fetal distress where delivery is not imminent
• Marked cephalopelvic disproportion suspected
• Previous cesarean section or uterine surgery affecting uterine integrity
• Six or more previous term pregnancies
• Unexplained vaginal bleeding
• Concurrent oxytocin use

Hospital Setting Requirement

Dinoprostone must only be administered by trained obstetrical personnel in a hospital with appropriate obstetrical care facilities 1, as emergency intervention may be required for complications such as uterine hyperstimulation or fetal distress.