What is the management for a multigravida (multiparous woman) at 39 weeks gestation with a cervix dilated to 5 cm after 4 hours, initially 4 cm dilated with strong and regular contractions?

Management of Protracted Active Phase Labor in a Multigravida

The appropriate management is oxytocin augmentation (Option B), as this represents protracted active phase labor with inadequate cervical change (only 1 cm over 4 hours) despite strong contractions, and oxytocin is the first-line treatment when cephalopelvic disproportion is not evident. 1, 2

Diagnosis: Protracted Active Phase Labor

• This multigravida has progressed only 1 cm (from 4 to 5 cm) over 4 hours despite strong and regular contractions, meeting criteria for protracted active phase labor 1, 2
• While contractions are described as "strong and regular," this clinical assessment may not reflect adequate uterine contractility (ideally measured as 200+ Montevideo units), which is necessary to rule out inadequate contractions as the cause 1
• The normal expected progression in active labor for a multigravida should be faster than what is observed here 3

Why Oxytocin is the Correct Choice

• The American College of Obstetricians and Gynecologists recommends oxytocin augmentation as first-line treatment for active phase arrest when cephalopelvic disproportion (CPD) is not evident, with a 92% success rate for vaginal delivery 2
• Before initiating oxytocin, assess for CPD (which occurs in 25-30% of active phase abnormalities), considering factors such as fetal macrosomia, malposition, or pelvic adequacy 1, 2
• In this case, there is no mention of concerning fetal size, malpresentation, or maternal pelvic abnormalities that would suggest CPD 1

Oxytocin Administration Protocol

• Initial dosing should be no more than 1-2 mU/min, with gradual increases in increments of no more than 1-2 mU/min until adequate contraction pattern is established 4
• Prepare solution by combining 10 units oxytocin with 1,000 mL non-hydrating diluent (creating 10 mU/mL concentration) 4
• Use an infusion pump for accurate control of infusion rate, as this is essential for safe administration 4

Expected Timeline with Oxytocin

• When oxytocin is just started in early first stage, it may take up to 10 hours for the cervix to dilate by 1 cm 3
• Once effective uterine contractions are achieved and cervix is dilated more than 5 cm, cervical dilation to the next centimeter occurs within 2 hours in 95% of cases in both nulliparas and multiparas 3
• After reaching effective contractions under oxytocin, the 95th percentile time from 5-6 cm is 1.1 hours in multiparas 3

Critical Monitoring Requirements

• Continuous fetal heart rate monitoring is mandatory during oxytocin administration to detect signs of fetal distress 2, 4
• Monitor uterine contraction strength, frequency, and duration continuously 1, 4
• Perform serial cervical examinations to evaluate progress 1
• Discontinue oxytocin immediately if signs of uterine hyperactivity or fetal distress develop 2, 4

Why Other Options Are Incorrect

• Option A (Cesarean section): Premature at this stage without attempting oxytocin augmentation first, as vaginal delivery success rate is 92% with oxytocin 2
• Option C (Amniotomy): Artificial rupture of membranes for arrested dilation has no objective evidence of being useful treatment 5
• Option D (Reassess after 2 hours): Inappropriate delay without intervention; active management with oxytocin should begin now rather than waiting 1, 2

Reassessment Criteria

• If no progress occurs after 4 hours of adequate oxytocin augmentation (achieving 200+ Montevideo units), reassess for CPD 1, 2
• Proceed to cesarean delivery if evidence of CPD emerges during augmentation or if labor fails to progress despite adequate oxytocin 1, 2
• Maintain intrauterine pressure monitoring if available to ensure adequate contraction strength 1

Common Pitfalls to Avoid

• Do not delay oxytocin initiation by simply observing—this represents inadequate labor progress requiring intervention 1, 2
• Do not perform amniotomy as primary intervention, as it lacks evidence for effectiveness in labor arrest 5
• Do not proceed directly to cesarean section without attempting oxytocin augmentation unless CPD is evident 2
• Ensure adequate monitoring is in place before starting oxytocin to detect complications early 4