Hutton Eileen K, Simioni Julia C, Thabane Lehana
Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada.
Midwifery Education Program, McMaster University, Hamilton, Ontario, Canada.
Acta Obstet Gynecol Scand. 2017 Aug;96(8):1012-1020. doi: 10.1111/aogs.13161. Epub 2017 May 27.
Among women with a fetus with a non-cephalic presentation, external cephalic version (ECV) has been shown to reduce the rate of breech presentation at birth and cesarean birth. Compared with ECV at term, beginning ECV prior to 37 weeks' gestation decreases the number of infants in a non-cephalic presentation at birth. The purpose of this secondary analysis was to investigate factors associated with a successful ECV procedure and to present this in a clinically useful format.
Data were collected as part of the Early ECV Pilot and Early ECV2 Trials, which randomized 1776 women with a fetus in breech presentation to either early ECV (34-36 weeks' gestation) or delayed ECV (at or after 37 weeks). The outcome of interest was successful ECV, defined as the fetus being in a cephalic presentation immediately following the procedure, as well as at the time of birth. The importance of several factors in predicting successful ECV was investigated using two statistical methods: logistic regression and classification and regression tree (CART) analyses.
Among nulliparas, non-engagement of the presenting part and an easily palpable fetal head were independently associated with success. Among multiparas, non-engagement of the presenting part, gestation less than 37 weeks and an easily palpable fetal head were found to be independent predictors of success. These findings were consistent with results of the CART analyses.
Regardless of parity, descent of the presenting part was the most discriminating factor in predicting successful ECV and cephalic presentation at birth.
在胎儿为非头先露的女性中，外倒转术（ECV）已被证明可降低出生时臀先露和剖宫产的发生率。与足月时进行ECV相比，在妊娠37周前开始进行ECV可减少出生时非头先露婴儿的数量。这项二次分析的目的是调查与成功进行ECV手术相关的因素，并以临床实用的形式呈现这些因素。
数据收集自早期ECV试点试验和早期ECV2试验，这两项试验将1776例胎儿为臀先露的女性随机分为早期ECV组（妊娠34 - 36周）或延迟ECV组（妊娠37周及以后）。感兴趣的结局是成功的ECV，定义为手术后及出生时胎儿为头先露。使用两种统计方法研究了几个因素对预测成功ECV的重要性：逻辑回归和分类与回归树（CART）分析。
在初产妇中，先露部未衔接和胎儿头部易于触及与成功独立相关。在经产妇中，先露部未衔接、妊娠小于37周和胎儿头部易于触及被发现是成功的独立预测因素。这些发现与CART分析的结果一致。
无论产次如何，先露部下降是预测成功ECV和出生时头先露的最具鉴别力的因素。
