Pelvimetry by magnetic resonance imaging in breech presentation.

Evaluation of the pelvis by pelvimetry plays an important role in selecting patients with term breech presentation for possible vaginal delivery. X-ray pelvimetry involves the disadvantage of fetal exposure to ionizing radiation. Computed tomography reduces the amount of radiation markedly, but there is still a risk. Ten patients with breech presentation at term underwent antepartum pelvimetry with magnetic resonance imaging, following by postpartum magnetic resonance pelvimetry and x-ray pelvimetry. Measurements with magnetic resonance imaging are as reliable as those obtained with x-ray pelvimetry and the contrast of the magnetic resonance images is even better. The advantages of magnetic resonance pelvimetry are clear: no ionizing radiation and reliable pelvimetry results in cases of term breech presentation in which a normal pelvis is a prerequisite for safe vaginal delivery.