摘要
目的：难产是指产力、产道、胎儿及精神心理因素中的任何一个或一个以上的因素发生异常以及四个因素间相互不能适应，而使分娩进展受到阻碍，若处理不当可给母儿带来严重的危害。而在妊娠分娩中95%以上是头位，所以头位难产是每一个产科工作者经常遇到的问题。在头位难产中，产道、胎儿、产力三个因素间有着错综复杂的关系，难产的形成很难截然地归诸于其中的某一因素，更可能是复合因素作用的结果。本研究探讨了超声测量胎儿生物学径线及母体骨盆入口前后径（真结合径）的方法，提出了超声预测胎儿体重的恰当公式，并比较了胎儿各径线与母体骨盆入口前后径间的相互关系，为临床工作者提供理论依据，力争在产前预防难产的发生，减少母婴并发症。
方法：1、 使用ATL HDI 5000彩色多普勒超声诊断仪对我院产科200例37~42周单胎孕妇行超声测量。
2、 于分娩前1~3天内、临产之前，测量胎儿双顶径（BPD）、头围（HC）、腹围（AC）、股骨长（FL）、双肩径、单侧锁骨长、单侧肩胛骨长、体重等参数，并与生后即刻、24小时、48小时的实际测量值做对比研究。
3、 BPD、HC、FL等参数的超声测量采用国际通用的测量平面及方法；AC的测量平面为胎心尾侧与胎肾头侧间的前
后向胎腹横切声像，切面内显示脊柱、双肾上极、脐静脉矢状部，但无胎心声像。测量时沿胎腹外缘描记。双肩径的测量方法为胎儿第七颈椎中心至一侧肩峰的距离×2；单侧锁骨长的测量方法为在肱骨短轴切面显示的近似“S”形锁骨回声，测量其肩峰端与胸骨端的距离；肩胛骨的测量方法为测量肩胛骨上角和外角间的距离。
4、 新生儿测量：BPD的测量方法为：两侧顶骨最外缘间的距离；HC的测量方法为：经眉弓上方、枕后结节绕头一周的长度；AC的测量方法为：剑突与脐之间中点绕腹一周的长度；股骨长的测量方法为：股骨两远侧端的距离；锁骨长的测量方法为：锁骨肩峰端与胸骨端的距离；肩胛骨的测量方法为：肩胛骨上角与外角间的距离；双肩径的测量方法为：两侧肩峰外侧缘间的距离。
5、 超声测量母体骨盆入口前后径（即耻骨联合上缘中点至骶骨岬前缘正中间的距离），并与剖宫产术中的实际测量值做对比研究。
6、 将胎儿单侧锁骨长、单侧肩胛骨长与新生儿双肩径做相关分析。
7、 比较胎儿生物学径线与巨大儿的关系。
8、 依据分娩方式不同，将研究对象分为阴道分娩组、试产失败剖宫产组及其他因素剖宫产组，将各组的超声测量值与实际测量值做对比研究；分别比较不同分娩方式组胎儿生物学径线与母体骨盆入口前后径间的相互关系。
结果：1、 阴道分娩组（91例）：超声测量值（BPD：9.373±0.284cm、HC：33.159±1.013cm）与生后24小时测量
值（BPD：9.412±0.299cm、HC：33.285±0.985cm）及生后48小时测量值（BPD：9.411±0.288cm、HC：33.312±0.985cm）间无显著差异（P＞0.05）；与生后即刻测量值（BPD：9.028±0.245cm、HC：32.587±1.002cm）比较存在显著差异（P＜0.05）。AC、FL的超声测量值（AC：33.719±1.269cm、FL：7.328±0.152cm），生后即刻测量值（AC：33.443±1.243cm、FL：7.315±0.147cm），生后24小时测量值（AC：33.713±1.137 cm、FL：7.352±0.161cm），生后48小时测量值（AC： 33.676±1.243 cm、FL：7.379±0.157cm）间无统计学差异（P＞0.05）。试产失败剖宫产组（47例）和其他因素剖宫产组（62例）的BPD、HC、AC、FL等参数的超声测量值、生后即刻、24小时、48小时测量值间无显著差异（P＞0.05）。
2、 超声测量锁骨长（3.619±0.276cm）、肩胛骨长（3.449±0.254cm）、体重（3336.126±319.437kg）与生后24小时测量的锁骨长（3.610±0.274cm）、肩胛骨长（3.446±0.258cm）、体重（3356.021±329.920kg）间无显著差异（P＞0.05），但双肩径的生后测量值（11.267±0.810cm）高于超声测量值（10.830±1.154cm），存在显著差异（P＜0.05）。
3、 骨盆入口前后径的超声测量值（11.809±0.264cm）与术中测量值（11.835±0.266cm）比较无显著差异（P=0.353）。
4、 不同性别胎儿的BPD、HC、AC、FL、体重等参数无统计学差异（P＞0.05）；相同性别胎儿BPD、HC、AC、FL、体重的超声测量值与新生儿实际测量值间无统计学差异（P＞0.05），但男性体重预测值较实际测量值偏低、女性体重预测值较实际测量值偏高；男性胎儿的单侧锁骨长、肩胛
骨长、新生儿双肩径大于女性的相应参数值，存在统计学差异（P＜0.05）。
5、 在预测胎儿体重所使用的六种公式中，由公式Ⅰ、Ⅴ、Ⅵ预测的胎儿体重与新生儿实际体重之间存在统计学差异（P＜0.05）；而由公式Ⅱ、Ⅲ、Ⅳ预测的胎儿体重与新生儿实际体重间有良好的临床符合性（P＞0.05）。其中公式Ⅱ、Ⅳ对胎儿体重的预测值优于公式Ⅲ，以绝对误差≤250g为符合标准，公式Ⅱ、Ⅲ、Ⅳ的预测符合率分别为91%、82.5%、86%。
6、 胎儿体重预测的误差主要来自于腹围，在枕前位、枕后位及枕横位的测量中，腹围测量值偏大致使胎儿体重预测值大于实际体重（P＜0.05），其中尤以枕后位明显；而腹围测量值偏小使体重预测值小于实际体重时，体重预测值与实际体重间无统计学差异（P＞0
Objective: Dystocia prefered one or more than one of the factors consisting of the force of labor, birth canal, fetus, mental and phychological factors took place abnormal or the four factors didn’t compare with each other, which could prevent the progression of delivery. Dystocal could lead to fetal and maternal damage or death if not managed properly. While there were more than 95% of fetal positions in delivery were vertex delivery, so vertex dystocia was the most common question, which every obstetrician often faced. In the vertex dystocia there were complex correlations among the birth canal, fetus and force of labor. It was singular if the dystocia was caused by a single factor. The more probable result was the function of compound factors. This study was designed to evaluate the methods of fetal biological diameters and conjugata of the pelvic inlet (conjugata vera) measured by ultrasound; preferred the propriet formular evaluating fetal weight by ultrosound and compared the correlations between the fetal biological diameters and conjugata of the pelvic inlet. We provided valuable theories for the clinicians to prevent the occuring of dystocia and reduce the complications of dystocia.
Methods: 1、 A total of 200 women at 37~42 week’s gestation, delivering a singleone infant measured by ATL HDI 5000 ultrasound diagnostic apparatus.
2、 The study measured fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), bishoulder distance (BSD), clavicula length (CL), scapula length (SL) and evaluated fetal weight within 3 days before labor. Compared these parameters with those measured at eftsoon, 24 hours, 48 hours after delivery.
3、 The used measuring plans and methods of BPD, HC, FL were the international standard plans and methods; The measuring plan of AC was the image of fetal abdomen between the margo tail of fetal heart and the margo head of fetal kidney, which concluded spinal column, kidney superior and sagittal section of umbilical vein, but didn’t conclude fetal heart. Bishoulder distance was the two diploid distances between the center of number seven fetal cervical vertebra and acromialis. Clavicula length was the distance between the extremitas acromialis and extremitas sternalis of clacicula in the image of humeral short axis. Scapul length was the distance between the angulus superior and angulus lateralis of scapula.
4、 The newborn measurements: BPD was the two margo lateralis distances of os parietale. HC was the head circumference along arcus superciliaris and protuberantia occipitalis externa. AC was the length along the plan of abdomen
at the center of umbilical and sternalis. FL was the length of femur. BSD was the distance of margo lateralis of two acromialis. CL was the distance of the extremitas acromialis and extremitas sternalis of clacicula. SL was the diatance of the angulus superior and angulus lateralis of scapula.
5、 The study measured conjugata of the pelvic inlet (the distance between the center of the pubic symphysis and the center of os sacrum promontorium’s margo anterior) by ultrasound and compared with the actual distance measured in cesarean.
6、 Correlation analyses were performed between fetal CL, SL and newborn BSD respectively.
7、 Correlations were performed between fetal biological diameters and fetal macrosomic.
8、 According as partal mode, the study objects were devided into vaginal delivery group (91 cases), cesarean delivery group after trial-produce failure (47 cases) and cesarean delivery group caused by other factoes (62 cases). The values measured by ultrasound of each group were compared with actual values by t-test; analysised the correlation between fetal biological diameters and conjugata of the pelvic inlet.
Results: 1、 Vaginal delivery group (91 cases): No significant difference of BPD, HC measured by ultrasound could be deduced compared to those measured at 24 hours and 48 hours after delivery (P＞0.05). There was a significant difference
of BPD, HC measured b
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