What is the management approach for mild Cephalopelvic Disproportion (CPD) with a pelvis less than just adequate causing prolonged labor?

From the Guidelines

Mild Cephalopelvic Disproportion (CPD) with a pelvis less than just adequate causing prolonged labor should be managed with careful observation, augmentation of labor with oxytocin, and consideration of cesarean delivery if progress is inadequate or fetal distress develops. The management approach for mild CPD involves a 2-phased approach, consisting of evaluation for known associations and intervention appropriate to the association found 1. The clinical importance of arrested active phase is its strong association with CPD and the related potential risks, with fully 40% to 50% of parturients with arrest of the active phase having concomitant CPD 1.

Key considerations in the management of mild CPD include:

• Thorough cephalopelvimetry to exclude the presence of disproportion 1
• Administration of oxytocin to enhance uterine contractions, with careful monitoring of fetal well-being 1
• Continuous fetal monitoring to detect any signs of fetal distress 1
• Maternal positioning to optimize pelvic dimensions, such as hands and knees, lateral decubitus, or squatting 1
• Adequate pain management, including epidural anesthesia, to prevent maternal exhaustion and promote relaxation 1

If progress remains inadequate despite these measures, or if fetal distress develops, cesarean delivery is a more prudent and safer choice 1. The risks of damage to the mother and fetus are too great to contemplate an attempt at vaginal delivery, which is unlikely to be achievable, let alone safely 1. Other strong associations, such as maternal diabetes and obesity, pelvic shape and size, fetal macrosomia, malposition, and excess molding, should also be considered and managed accordingly 1.

In summary, the management of mild CPD with a pelvis less than just adequate causing prolonged labor requires careful observation, augmentation of labor, and consideration of cesarean delivery if progress is inadequate or fetal distress develops, with the goal of minimizing risks to the mother and fetus.

From the FDA Drug Label

Except in unusual circumstances, oxytocin should not be administered in the following conditions: ... borderline cephalopelvic disproportion... The management approach for mild Cephalopelvic Disproportion (CPD) with a pelvis less than just adequate causing prolonged labor is to avoid oxytocin administration in most cases, as it may exacerbate the condition and lead to further complications.

• The use of oxytocin is generally contraindicated in cases of significant cephalopelvic disproportion, and borderline CPD is also a precautionary condition 2.
• In cases where oxytocin is considered, it should be used with extreme caution and under close monitoring by trained personnel, as the risk of hypertonic contractions and other complications is increased.
• The decision to use oxytocin in mild CPD should be made on a case-by-case basis, weighing the potential benefits against the risks, and considering alternative management options. 2

From the Research

Definition and Causes of Mild CPD

• Mild Cephalopelvic Disproportion (CPD) occurs when there is a mismatch between the size of the fetal head and the size of the maternal pelvis, resulting in prolonged labor 3.
• A pelvis less than just adequate can cause prolonged labor due to the mechanical obstruction of the fetal head 4, 5.

Management Approach for Mild CPD

• The management approach for mild CPD involves careful observation and sufficient trials of labor to decrease the rate of cesarean section and increase obstetric quality 4.
• Oxytocin augmentation can be used to enhance uterine activity and promote labor progress, but it is essential to monitor the dose and duration of augmentation to avoid complications 5, 6.
• Clinical pelvimetry still has a place in obstetrics for predicting or confirming CPD, but it requires appropriate training and repeated practice to become a useful clinical skill 3.

Outcomes and Predictions

• The outcome of trial labor after a previous cesarean for strictly defined CPD is favorable, with 68% of women achieving vaginal delivery in their next pregnancy 7.
• A satisfactory rate of cervical dilatation in the presence of optimal uterine activity is predictive of a favorable outcome when oxytocin is used for dysfunctional labor after a previous cesarean section 6.
• The diagnosis of CPD should be made carefully after observation in the labor stage and sufficient trials of labor to avoid unnecessary cesarean sections 4, 5.