From the Guidelines
Cephalopelvic disproportion (CPD) assessment requires a systematic approach combining clinical evaluation and imaging, with the ultimate goal of preventing maternal trauma, fetal injury, or both, by identifying those who would benefit from cesarean delivery 1. The assessment process begins with a thorough history, noting risk factors such as maternal diabetes, previous difficult deliveries, or suspected macrosomia. Physical examination should include:
- Maternal height, weight, and body habitus assessment, as short stature (<150 cm) may indicate a small pelvis
- Leopold's maneuvers to estimate fetal size, position, and engagement
- Clinical pelvimetry involves examining the pelvic inlet, mid-pelvis, and outlet through vaginal examination, assessing the diagonal conjugate, ischial spines prominence, and pubic arch angle During labor, monitor progress using a partogram, as arrest of descent or dilation despite adequate contractions suggests CPD. Imaging studies include:
- Ultrasound for estimated fetal weight and head circumference
- X-ray or CT pelvimetry may be used in select cases to measure pelvic dimensions
- MRI offers detailed assessment without radiation but is less commonly used If CPD is diagnosed, cesarean delivery is typically indicated, as attempting vaginal delivery could lead to maternal trauma, fetal injury, or both 1. The assessment should be dynamic throughout pregnancy and labor, as CPD may only become apparent during the active phase of labor when the fetal head attempts to navigate the maternal pelvis. Recent studies suggest that advanced imaging techniques, such as 3- or 4-dimensional sonography, may be used to assess for possible CPD with greater sophistication, accuracy, and nuanced clinical interpretation 1. However, the current evidence supports the use of clinical evaluation and imaging as the primary methods for assessing CPD.