Question: Anytime a mother fails to bring the fetus down into the pelvis to deliver vaginally, he does a C/S, and the dx he attaches to it every time is CPD. Wouldn’t FTP/arrested phase of labor or something along those lines be more accurate, especially if there has been no indication of a large fetal head throughout the pregnancy? When would be the appropriate time to use CPD versus FTP? New Jersey Subscriber Answer: Cephalopelvic disproportion (CPD) occurs when a baby’s head or body is too large to fit through the mother’s pelvis. Most clinical articles indicate that true CPD is rare, but many cases of “failure to progress” during labor are given a diagnosis of CPD incorrectly. The code category O33.- (Maternal care for disproportion…) defines the various reasons for disproportion, while the code categories of O64- (Obstructed labor due to malposition and malpresentation of fetus…), O65.- (Obstructed labor due to maternal pelvic abnormality…), and O66.- (Other obstructed labor…) list the reasons during labor. ICD-10 does not give a specific definition for CPD but does reference the term in the index to O33.9 (Maternal care for disproportion, unspecified). But if you look at Williams Obstetrics (page 496), you will see a really good explanation of CPD versus failure to progress. Your OB probably has a copy of this book, so you should access it; together, you may be able to come up with a better understanding of the codes you should be reporting.