The indications recognized as valid in modern practice for the exhibition of cesarean section are numerous. Historically, this operation has been employed only for high degrees of fetopelvic disproportion. Indeed, until about fifty years ago its validity on any other grounds was not recognized. Up to that time it was so dangerous as to be applicable only to what was known as the absolute degree of pelvic contracture, because of which not even a mutilated dead baby could be otherwise removed from its mother's body, and the relative degree of contracture, which meant that a living baby could scarcely be otherwise delivered.
In the last forty to fifty years, however, the term relative disproportion has become so liberalized as to connote any degree of fetopelvic disproportion which makes vaginal delivery unusually difficult or carries more than a minimum hazard for the baby's survival in vaginal delivery. This trend, while undoubtedly
COSGROVE SA, NORTON JF. CESAREAN SECTIONINDICATIONS FOR AND RELATIVE MERITS OF THE CLASSIC, LOW AND EXTRAPERITONEAL OPERATIONS. JAMA. 1942;118(3):201–204. doi:10.1001/jama.1942.02830030019004