What are the two types of cephalopelvic disproportion (CPD)?

The classification of cephalopelvic disproportion (CPD) into true and relative forms is vital for understanding how this condition can impact labor and delivery. True CPD occurs when the fetal head is too large to fit through the mother's pelvic inlet due to a persistent mismatch between the size of the fetus and the anatomy of the mother’s pelvis. This situation often leads to an obstructed labor, requiring careful management and often cesarean delivery.

Relative CPD, on the other hand, can occur even when the dimensions of the fetal head and the pelvis are not drastically mismatched. This situation may arise due to factors such as the position of the fetus, labor progress, or the mother’s exhaustion during labor. It suggests that although the anatomy might not be entirely incompatible, there are other factors at play affecting the delivery process, potentially leading to prolonged labor or complications.

Understanding these two types assists healthcare providers in making informed decisions regarding labor management, interventions, and potential surgical options. The other classifications mentioned, such as complete and partial, obstructive and functional, or primary and secondary, do not align with how CPD is clinically identified in obstetric practice, focusing instead on other aspects of maternal and fetal dynamics.