A Postural Approach to the Pelvic Diameters of Obstetrics: The Dynamic External Pelvimetry Test

In recent years, there has been a renewed interest in internal and external pelvimetry, in relation to the diagnosis of dystocia from a "contracted pelvis." Dystocia is still one of the causes of maternal-fetal morbidity and mortality in the world. The main cause is the fetal-pelvic disproportion, of which mechanical dystocia and contracted pelvis are most probably involved. Clinical pelvimetry was the diagnostic method of "contracted pelvis" and still seems to have its place in the clinical obstetric routine. Studies have been conducted in order to measure anatomical diameters and correlate them with operative or vaginal delivery. Some studies have been published regarding the diameters' variation with the shifting of the patient's posture. The positions used in the research for the analysis of changes in pelvis measurements are the same as those used for centuries to assist and promote childbirth. This technical report is to define a method of measuring changes in classical pelvimetric external diameters in relation to the postural change of the subjects, taking into consideration the needs of the operators, the postural difficulties of pregnant women and the evidence acquired from instrumental research. It aims to propose a dynamic postural method suited to daily practice, according to the directives and principles of the classical external obstetric pelvimetry.