Academic Department of Obstetrics & Gynaecology, Trinity College Dublin & Coombe Women & Infant's University Hospital, Dublin, Ireland.
BMC Pregnancy Childbirth. 2012 Sep 13;12:95. doi: 10.1186/1471-2393-12-95.
Instrumental deliveries are commonly performed in the United Kingdom and Ireland, with rates of 12 - 17% in most centres. Knowing the exact position of the fetal head is a pre-requisite for safe instrumental delivery. Traditionally, diagnosis of the fetal head position is made on transvaginal digital examination by delineating the suture lines of the fetal skull and the fontanelles. However, the accuracy of transvaginal digital examination can be unreliable and varies between 20% and 75%. Failure to identify the correct fetal head position increases the likelihood of failed instrumental delivery with the additional morbidity of sequential use of instruments or second stage caesarean section. The use of ultrasound in determining the position of the fetal head has been explored but is not part of routine clinical practice.
METHODS/DESIGN: A multi-centre randomised controlled trial is proposed. The study will take place in two large maternity units in Ireland with a combined annual birth rate of 13,500 deliveries. It will involve 450 nulliparous women undergoing instrumental delivery after 37 weeks gestation. The main outcome measure will be incorrect diagnosis of the fetal head position. A study involving 450 women will have 80% power to detect a 10% difference in the incidence of inaccurate diagnosis of the fetal head position with two-sided 5% alpha.
It is both important and timely to evaluate the use of ultrasound to diagnose the fetal head position prior to instrumental delivery before routine use can be advocated. The overall aim is to reduce the incidence of incorrect diagnosis of the fetal head position prior to instrumental delivery and improve the safety of instrumental deliveries.
Current Controlled Trials ISRCTN72230496.
在英国和爱尔兰，器械分娩较为常见，大多数中心的比例为 12-17%。准确了解胎儿头部的位置是安全进行器械分娩的前提。传统上，通过描绘胎儿颅骨的缝线和囟门来进行经阴道数字检查，以诊断胎儿头部的位置。然而，经阴道数字检查的准确性可能不可靠，其准确率在 20%至 75%之间变化。如果无法识别正确的胎儿头部位置，器械分娩失败的可能性会增加，并且可能需要连续使用器械或行第二产程剖宫产，从而增加额外的发病率。已经探索了在确定胎儿头部位置时使用超声的方法，但它不是常规临床实践的一部分。
方法/设计：提出了一项多中心随机对照试验。该研究将在爱尔兰的两个大型产科单位进行，这两个单位的合并年分娩率为 13500 例。将涉及 450 名经阴道分娩的初产妇，这些产妇在 37 周妊娠后进行器械分娩。主要结局指标将是胎儿头部位置的不正确诊断。涉及 450 名妇女的研究将有 80%的效力来检测出胎儿头部位置不正确诊断的发生率差异为 10%，双侧 5%的α值。
在提倡常规使用之前，评估在器械分娩前使用超声诊断胎儿头部位置非常重要且及时。总体目标是减少器械分娩前胎儿头部位置不正确诊断的发生率，提高器械分娩的安全性。
当前对照试验 ISRCTN72230496。
