Eggebø T M, Heien C, Okland I, Gjessing L K, Smedvig E, Romundstad P, Salvesen K A
Department of Obstetrics and Gynaecology, Stavanger University Hospital.
Ultraschall Med. 2008 Apr;29(2):179-83. doi: 10.1055/s-2007-963017. Epub 2007 Jun 28.
To evaluate the proportion of fetal head rotation from occiput posterior (OP) to occiput anterior (OA) during labour after term prelabour rupture of membranes (PROM), and to study if OP before labour are associated with a higher risk of operative deliveries and a longer duration of labour.
A transabdominal ultrasound examination was performed in 152 women with PROM after 37 weeks with a single live fetus in cephalic position. The course of labour was compared in women with the fetal head in occiput posterior position or other positions before the start of labour.
Before the start of labour, 40 (26%) fetuses were in occiput posterior position (OP), but 34 (85%) of them rotated to occiput anterior (OA) during labour. Ten (6.6%) fetuses were delivered in OP, and six of them were in OP before the start of labour. There were no statistically significant associations between the head position before the start of labour and the duration from PROM to delivery, induction of labour, use of epidural analgesia, augmentation with oxytocin, operative deliveries, perineal tears, Apgar scores, pH or base excess in the umbilical artery.
Transabdominal ultrasound examination can determine the fetal head position before the start of labour, but the position of the head did not predict the course of labour, probably because the fetal head may rotate during labour even after PROM.
评估足月胎膜早破（PROM）后分娩期间胎儿头部从枕后位（OP）旋转至枕前位（OA）的比例，并研究临产前枕后位是否与更高的手术分娩风险和更长的产程相关。
对152例孕37周后单活胎头先露的胎膜早破妇女进行经腹超声检查。比较临产前胎儿头部处于枕后位或其他位置的妇女的分娩过程。
临产前，40例（26%）胎儿为枕后位（OP），但其中34例（85%）在分娩过程中旋转至枕前位（OA）。10例（6.6%）胎儿以枕后位分娩，其中6例在临产前即为枕后位。临产前的头部位置与胎膜早破至分娩的时间、引产、硬膜外镇痛的使用、缩宫素加强宫缩、手术分娩、会阴撕裂、阿氏评分、脐动脉pH值或碱剩余之间无统计学显著关联。
经腹超声检查可在临产前确定胎儿头部位置，但头部位置不能预测分娩过程，可能是因为即使胎膜早破后，胎儿头部在分娩过程中仍可能旋转。
