[Methods, techniques and assessment criteria in obstetric pelvimetry]

Size and shape of the bony pelvis are important factors determining the progress of labor and delivery. Clinical evaluation of the pelvis and sonographic examination of the fetal size are important tools for the planning of labor and in most cases allow to diagnose cephalopelvic disproportion. Pelvimetry by computed tomography (CT) and by magnetic resonance imaging (MRI) are exact and simple techniques with low or absent ionizing radiation. These new techniques offer distinct advantages over conventional X-ray pelvimetry. However, the value of the measurements of the pelvic dimensions in predicting labor outcome and in the diagnosis of cephalopelvic disproportion remains limited. Only if the pelvimetric data are combined with data on fetal dimensions obtained by ultrasound or by postpartum measurements, the efficacy of the examination in predicting the success of labor and identifying the presence or absence of cephalopelvic disproportion is increased. This combination therefore may confirm the diagnosis of cephalopelvic disproportion after operative delivery, which is important with respect to subsequent deliveries. Furthermore this method could play and important role in selecting patients with term breech presentation for possible vaginal delivery.