Inclusion Criteria:  Patients > 18 years of age Patient requiring pelvimetry (breech fetus) Gestation > 36 SA (weeks of amenorrhea) Patients with BMI < 30 Affiliated to social security or similarly regime Patients who gave their consent to participate in the study (Patient having agreed to perform both examinations: MRI and EOS system)  Exclusion Criteria:  Patient with a contraindication to MRI (claustrophobia, pace-maker, intracorporeal metallic element) Patient with a contraindication to performing EOS® (person not standing alone) Patient who are in exlusion period of another interventiionnal study Person deprived of freedom by judicial or administrative decision; person hospitalized for psychitric care; person under legal protection measure.