胎头入盆时枕骨取后位者,在分娩过程中大部份经宫缩推动而转成枕前位,但胎头俯屈较差者,枕骨不能转到前位时出现持续性枕后位,亦有少数病例系由枕横位转成。通常人们认为胎头不论在骨盆入口、中骨盆或盆底只要分娩经充分试产,产程将结束而胎头枕部仍未旋转至前位者称为持续性枕 Fetal head into the basin to take the posterior digit who during childbirth most of the contractions and pushed into the anterior occipital, but the poor fetal head flexion, the occiput can not be transferred to the front when the sustained occipital Bit, there are a few cases by the pillow transversal into. Usually people think that both in the pelvis entrance of the fetal head, the pelvis or pelvic floor as long as the childbirth as long as the pilot trial, labor will end and the head of the occipital has not yet rotated to the former known as persistent pillow