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

Management of Slow Labor Progression in a Multigravida at 39 Weeks

The correct management is oxytocin augmentation (Option B), as this patient has active phase protraction disorder requiring intervention to accelerate cervical dilation and prevent arrest. 1, 2, 3

Defining the Labor Abnormality

This multigravida demonstrates active phase protraction disorder, not arrest:

• Protraction is defined as slower-than-normal cervical dilation during active phase (progressing from 4 cm to 5 cm over 4 hours = 0.25 cm/hour) 4, 3
• Arrest requires no cervical change for ≥4 hours with adequate contractions (≥200 Montevideo units) after reaching ≥6 cm dilation 3, 5
• This patient is only at 5 cm and has progressed 1 cm, so arrest criteria are not met 3

Why Oxytocin is the Correct Answer

Oxytocin augmentation is first-line treatment for active phase protraction when cephalopelvic disproportion (CPD) is not evident, with a 92% success rate for vaginal delivery. 2

Oxytocin Administration Protocol:

• Start at 1-2 mU/min and increase by 1-2 mU/min increments until adequate contraction pattern is established 6
• Monitor fetal heart rate continuously and assess uterine contractions (target ≥200 Montevideo units) 1, 6
• Perform serial cervical examinations every 2 hours to evaluate progress 3
• Once effective contractions are achieved at >5 cm dilation, expect cervical dilation to next centimeter within 2 hours in 95% of cases 7

Why Other Options Are Incorrect

Option A (Cesarean Section): Premature and Inappropriate

• CPD occurs in only 25-30% of active phase abnormalities 2, 3
• Cesarean delivery should not be performed unless labor has arrested for minimum of 4 hours with adequate uterine activity at ≥6 cm dilation 5
• This patient has not met arrest criteria and is only at 5 cm 3, 5

Option C (Amniotomy): Not Evidence-Based as Sole Intervention

• There is no objective proof that amniotomy alone is useful treatment for protraction or arrest of dilation 4
• Routine amniotomy alone in normally progressing spontaneous labor cannot be recommended 5
• Amniotomy may be acceptable if needed for fetal monitoring electrode placement, but should be combined with oxytocin augmentation 4, 5

Option D (Reassess After 2 Hours): Delays Necessary Treatment

• Waiting another 2 hours without intervention risks progression to true arrest disorder 4, 3
• Early intervention with oxytocin for dysfunctional or slow labor is recommended to prevent complications 5
• The patient already has 4 hours of slow progress documented—further observation without intervention is not appropriate 1, 2

Critical Assessment Before Oxytocin

Before initiating oxytocin, assess for factors suggesting CPD: 4, 2, 3

• Fetal macrosomia (estimated fetal weight >4000g)
• Fetal malposition (occiput posterior or transverse)
• Excessive molding or asynclitism on examination
• Maternal factors: diabetes, obesity, small pelvic dimensions

If CPD is suspected or cannot be ruled out with reasonable certainty, cesarean delivery is safer than attempting vaginal delivery. 4

Monitoring During Oxytocin Augmentation

• Discontinue oxytocin immediately if signs of fetal distress or uterine hyperactivity occur 2, 6
• If no progress occurs after 4 hours of adequate oxytocin augmentation (≥200 Montevideo units), reassess for CPD and consider cesarean delivery 1, 2
• Maintain continuous fetal heart rate monitoring throughout augmentation 1, 6

Common Pitfall to Avoid

Do not diagnose arrest of labor before 6 cm dilation—this represents protraction disorder requiring oxytocin augmentation, not immediate cesarean delivery. 3, 5 The threshold of 6 cm is critical for distinguishing between latent phase (where longer times are acceptable) and active phase arrest (where intervention is mandatory). 4, 3