Xi’an Jiao Tong University First Hospital Ob&Gy Dept 异 常 分 娩 Dystocia Xi’an Jiao Tong University First Hospital Ob&Gy Dept

异常分娩 定义： 影响分娩的四因素（产力、产道、胎儿及精神心理）中的任何一个或几个因素发生异常，以及四个因素间互相不能适应，而使分娩进程受到阻碍，称为异常分娩，俗称难产。 Abnormalities that prevent or deviate from the normal course of labor and delivery are classified into different categories that are often interrelated; e.g., a contracted pelvis may increase the likelihood of fetal malpresentation. Malpresentation or excessive fetal size may be related to ineffective uterine action. Disproportion between pelvic architecture and the presenting part often accompany uterine dysfunction. Finally, a variety of extrinsic factors has been investigated and may have a role in dystocia. These include sedation, anxiety, anesthesia, supine position, unripe cervix, and chorioamnionitis.

分娩四因素 子宫收缩力 产力 腹肌力 肛提肌力 骨产道（骨盆） 产道 软产道 （外阴、阴道、宫颈、子宫下段） 胎儿位置 （胎产式、胎方位） 产力 腹肌力 肛提肌力 骨产道（骨盆） 产道 软产道 （外阴、阴道、宫颈、子宫下段） 胎儿位置 （胎产式、胎方位） 胎儿 胎儿大小 精神因素 A high level of anxiety during pregnancy has been associated with decreased uterine activity and with longer and dysfunctional labor. Abnormalities of the powers constitute uterine dystocia, hypertonic , hypotonic,or discoordinated uterine activity is characteristic of ineffective uterine action. Lack of voluntary expulsive effort during the second stage may also impede the normal course of delivery. Abnormalities of the passenger are known as fetal dystocia, ie, difficulties caused by abnormalities of the fetus. Common fetal abnormalities leading to dystocia include excessive fetal size, malpositions, congenital anomalies, and multiple gestation. Abnormality of the passage constitute pelvic dystocia, ie, aberrations of pelvic architecture and its relationship to the presenting part. Such abnormalities may be related to size or configurational alterations of the bony pelvis, soft tissue abnormalities of the birth canal, reproductive tract masses or neoplasia, or aberrant placental location.

发病率 既往30年中，剖宫产率增加 ； 难产是剖宫产的最主要原因 (>25%) ； 初产妇的难产发生率为: 10% 。 The diagnosis and management of dystocia is a major health care issue , because more than one fourth of all cesarean sections are performed for this indication. Because the goal of modern obstetrics is a safe , healthy delivery for both mother and the fetus, minimizing the morbidity and mortality of the labor process continues to be a primary focus of clinical attention.

异常分娩的类型 (1) 胎头下降延缓: 正常活跃期0.86cm/h 潜伏期延长: 正常需8hs左右 初产妇>16 hs 活跃期停滞: 正常3－4cm需1.5h，4－9cm需 2h，9－10需0.5h. < 1cm/ 2 h 胎头下降延缓: 正常活跃期0.86cm/h 活跃晚期 < 1 cm/h Labor is dynamic process characterized by uterine contractions that increase in regularity , intensity and duration, causing progressive dilatation and effacement of the cervix and descent of the fetus through the birth canal. The progress of labor is evaluated primarily through estimates of cervical dilatation and descent of the fetal presenting part. Normal labor patterns in primigravidas and multiparas have been describes by Freidman curve. Abnormal labor describes complications of the normal labor process: slower-than-normal progress (protraction disorder) or a cessation of progress (arrest disorder). Underlying pathogenesis of abnormal labor is multifactorial. The patterns of abnormal labor are summarized here.

异常分娩的类型(2) 胎头下降停滞 : 活跃晚期 先露不降 > 1h 第二产程延长: 初产妇 >2 h 经产妇 >1h 胎头下降停滞 : 活跃晚期 先露不降 > 1h 第二产程延长: 初产妇 >2 h 经产妇 >1h 第二产程停滞 先露不降 > 1h 滞产: 总产程 > 24 hs

潜伏期延长的原因 镇静剂使用过量 麻醉 宫颈未成熟 子宫因素 头盆不称

胎头下降及第二产程异常的原因 头盆不称 胎方位异常 麻醉 过量镇静剂 骨盆肿瘤

异常分娩各论 产力异常 (子宫性难产) Correct diagnosis and management of abnormal labor requires evaluation of the mechanisms of labor, in classic terms, the power , passenger and the passage, which are also referred to as…………

产力异常 (1) 正常宫缩的特点是什么？ 如何描述宫缩? 如何测量宫缩? 用手触诊 外置宫压探头 宫腔内压力传感器 子宫性难产 Uterine dystocia denotes any abnormality in the force of coordination of uterine contractility that prevents the normal progress of labor.

正常宫缩的特点 Increment: the building up and longest; acme – peak; and decrement or letting up.  Characteristics: frequency: time between beginning of one contraction to the beginning of the next. Duration: beginning to completion of a single contraction. Intensity – strength of contraction. Experienced nurse can estimate by palpating the fundus (top) during the contraction. Mild: the uterine wall can be indented; strong, it cannot be indented. Intensity can be measured directly with an intrauterine probe. Intensity of contraction: it describes the degree of uterine systole. The intensity gradually increases with advancement of labor until it becomes maximum in the second stage during delivery of the baby. During the first stage intrauterine cavity pressure is raised to 40-50mmHg and during second stage it is raised about to 100-120 mmHg. Frequency: in the early stage of labor, the contraction come at intervals of 10-15 min. The intervals gradually shorten with advancement of labor until in the second stage, when it comes every one or two minutes. Duration: in the first stage, the contraction lasts for about 30-40 seconds initially but gradually increases in duration with the progress of labor. Thus in the second stage, the contractions last longer than in the first stage. After contractions there is a intermittent. As labor progress, the intensity increase, frequency increase, contractile duration prolong and intermittent shorten gradually, by the end of the first stage of labor the contraction may come every 1 to 2 minutes and may last as long as a minute Intermittent : The intermittent nature of the contractions is of great importance to both the fetus and the mother. During a contraction the circulation to the placental bed through the uterine wall is stopped; if the uterus contracted continuously the fetus would die from lack of oxygen. The intermittent allow the placental circulation to be re-established and give the mother time to recover from the fatigue effect of the contraction. The uterus is a large muscle and contractions use up a lot of energy, if continued too long this would produce maternal exhaustion.

产力异常 (2) 产力异常分类 2. 宫缩过强 宫缩乏力 低张性宫缩乏力: 原发性; 继发性 b. 高张性宫缩乏力 协调性宫缩过强 低张性宫缩乏力: 原发性; 继发性 b. 高张性宫缩乏力 协调性宫缩过强 无阻力时: 急产 有阻力时:病理性缩复环 b. 非协调性 强直性宫缩 痉挛性狭窄环 2. 宫缩过强 Uterine dystocia denotes any abnormality in the force or coordination of uterine contractility that prevents the normal progress of labor.

产力异常 (3) 之低张性宫缩乏力 特点 强度不足 (宫压<15mmHg) 间歇时间长和/或节律不规律 原因: 产力异常 (3) 之低张性宫缩乏力 特点 强度不足 (宫压<15mmHg) 间歇时间长和/或节律不规律 原因: 1.头盆不称或胎先露异常 2. 双胎、羊水过多, 子宫过度扩张。 3. 过量镇静剂 4. 过早使用麻醉剂 5. 精神因素

产力异常 (4) 低张性宫缩乏力之处理 排除产道和胎儿异常： 如头盆不称、胎儿窘迫 ----如有则剖宫产终止分娩 产力异常 (4) 低张性宫缩乏力之处理 排除产道和胎儿异常： 如头盆不称、胎儿窘迫 ----如有则剖宫产终止分娩 单纯的宫缩乏力，催产素效果好 继发性或不协调性宫缩乏力，可用杜冷丁和安定 积极处理: 人工破膜，与宫颈Bishop评分直接相关 预防产后出血

宫颈 Bishop 评分 参数 分值 1 2 3 1-2 3-4 5-6 0-30 40-50 60-70 80-100 -3 -2 1 2 3 宫口扩张 1-2 3-4 5-6 宫颈管消退 0-30 40-50 60-70 80-100 胎先露位置 -3 -2 -1-0 +1- +2 宫颈质地 硬 中 软 宫口位置 后 前 9 100% successful 4-6 50% successful 7-9 80% successful ≤3分,均失败; 4~6分成功率为50%; 7~9分为80%; >9分均成功

分娩过程中宫颈的变化 初产妇 经产妇 宫口扩张 宫颈管消退 9 100% successful 4-6 50% successful

产力异常 (5) 之高张性宫缩乏力 特点 病因: 间歇期变短 胎盘早剥 宫缩间歇期宫压升高 滥用催产素 非协调性宫缩 头盆不称 通常为原发性 产力异常 (5) 之高张性宫缩乏力 特点 间歇期变短 宫缩间歇期宫压升高 非协调性宫缩 通常为原发性 病因: 胎盘早剥 滥用催产素 头盆不称 胎先露异常

产力异常 (6) 高张性宫缩乏力的处理 杜冷丁和安定 头盆不称或胎儿窘迫 ----剖宫产

产力异常 (7) 宫缩过强 协调性宫缩过强 节律和极性正常 宫压过高 无头盆不称存在: 急产－－总产程<3 hs, 产力异常 (7) 宫缩过强 协调性宫缩过强 节律和极性正常 宫压过高 无头盆不称存在: 急产－－总产程<3 hs, 头盆不称或胎位异常或瘢痕子宫：子宫破裂 非协调性宫缩过强 痉挛性缩复环 强直性子宫收缩: 子宫破裂

产力异常 (8) 宫缩过强 病因: 胎盘早剥 滥用宫缩剂 头盆不称 胎位异常

产力异常 (9) 宫缩过强 对母儿的危害 产伤, 软产道裂伤, 子宫破裂 感染，产后出血 胎儿窘迫 新生儿窒息、颅内出血、骨折

产力异常 (10) 宫缩过强的处理 如果由使用催产素引起：立即停用催产素。 硫酸镁及其他解痉药物 如上处理无效、或存在头盆不称、胎儿窘迫 产力异常 (10) 宫缩过强的处理 如果由使用催产素引起：立即停用催产素。 硫酸镁及其他解痉药物 如上处理无效、或存在头盆不称、胎儿窘迫 ----剖宫产 注意子宫切口的缝合 预防产后出血和感染

产力异常 (11) 第二产力（腹肌、盆底肌等）不足 产力异常 (11) 第二产力（腹肌、盆底肌等）不足 原因： 麻醉 镇静过度 疲乏 神经系统异常如：截瘫、 偏瘫或精神异常。 处理： 少量应用镇静剂；等待麻醉、镇静药物代谢一段时间，使肌力自然恢复。 第二产程使用产钳 3.

产道异常 骨盆异常 软组织梗阻 胎盘位置异常 Pelvic dystocia, particularly that due to small bony architecture, is the most common cause of passage abnormalities. The etiology and diagnosis of pelvic abnormalities begins with the shape, classificaiton and clinical assessment of the adult female pelvis.

骨产道异常 骨盆类型: 女 型 男 型 类人猿型 扁平型

女 型 男 型 骨盆入口 骨盆出口 骨盆腔 耻骨弓

骨产道异常（2） 骨盆测量: X-线骨盆测量、 骨盆外测量 IS, 髂棘间径 23－26cm IC,髂嵴间径 25-28cm EC, 骶耻外径 18-20cm IT, 坐骨结节间径 8.5-9.5cm 耻骨弓 > 90°

骶耻外径 18-20 cm

坐骨结节间径 : 8.5-9.5 cm

骨产道异常（3） 骨盆内测量 DC 对角径 12.5－13cm （骶岬不可及>12.5cm） 坐骨棘间径 10cm 骨盆内聚情况 骶骨凹度、骶尾关节活动度、尾骨、耻骨弓角度

对角径: 12.5-13cm

骨产道异常（4） 骨盆异常分类：入口、 中骨盆－出口狭窄 骨产道异常（4） 骨盆异常分类：入口、 中骨盆－出口狭窄 骨盆入口平面狭窄 I: 临界性狭窄 (大多数人可以自然经阴道分娩) EC = 18cm 入口前后径=10cm II: 相对性狭窄 (可以试产) EC = 16～18cm 入口前后径=8～10cm III: 绝对狭窄 ( 不试产，直接剖宫产) EC ≤16cm 入口前后径≤ 8cm

骨产道异常（5） 骨盆入口平面狭窄 临床表现 浮游头: 跨耻征可疑 (I 度和 II度狭窄时) 胎先露异常 : 臀先露、颜面先露、肩先露、不均倾。 第一产程延长 ：胎头塑性, 先锋头(I 度和 II度狭窄时) 病理性缩复环, 子宫破裂(III度狭窄时) 脐带脱垂/先露

跨耻征

跨耻征可疑时纠正实验

骨产道异常（6） 骨盆入口平面狭窄的处理 对骨盆入口狭窄漏诊的病历已少见 孕期及分娩过程中，持续的产程监护及催产素的合理应用也减少了因骨盆入口狭窄而导致的难产。 绝对骨盆入口狭窄产妇只能及时剖宫产终止妊娠，以防发生子宫破裂并减少围产儿病率。 In modern practice, in which the patient’s progress is compared with known labor curves and possible inlet contraction is suspected on the basis of clinical examination, neglected cases of inlet contraction are rare and the prognosis is excellent. With continuous fetal monitoring in these cases, fetal well-being may be ensured, even with concurrent use of dilute oxytocin. Cesarean section is the treatment of choice in true inlet contraction.

骨产道异常（7） 中骨盆－ 出口平面狭窄 中骨盆及骨盆出口平面的面积 中骨盆或出口平面狭窄很少单独出现 骨盆测量: 骨盆壁内聚, 坐骨棘突出, 坐骨切迹小，耻骨弓角度小 The obstetric midpelvis is defined as that area bounded by an anteroposterior diameter extending from the inferior border of the symphysis pubis through the ischial spines to the sacrum at approximately the junction of the fourth and fifth sacral vertebrae, combined with the transverse diameter between the ischial spines. The intersection of these 2 lines at the same point of the sacrum constitutes the posterior sagittal diameter of the midplane; the intersection of these 2 lines at the inferior border of the symphysis pubis constitutes the anterior sagittal diameter of the midplane. Critical values for these diameters are 11.5 cm for the anterior sagittal diameter, 9.5 cm for the interspinous diameter, and 5 cm for the posterior sagittal diameter. The criteria for estimating midpelvic adequacy include the sum of the posterior sagittal diameter and interspinous diameter, which should be greater than 13.5 cm.

骨产道异常（8） 中骨盆－出口平面狭窄 中骨盆－出口平面狭窄 坐骨棘间径 ≤8cm IT≤ 5.5cm I: 临界性狭窄 II: 相对性狭窄 坐骨棘间径 = 8.5～9.5cm IT=6.0～7.0cm III: 绝对狭窄 坐骨棘间径 ≤8cm IT≤ 5.5cm

骨产道异常（9） 中骨盆－出口平面狭窄的临床表现 活跃期和第二产程延长 持续性枕后位或枕横位 宫缩乏力常为继发性 胎头塑性或先锋头

骨产道异常（10） 中骨盆－出口平面狭窄的临床表现 持续胎头压迫可能造成组织坏死 －－－阴道直肠瘘或膀胱阴道瘘 甚至发生－－－子宫破裂 以上并发症常因不恰当的中位产钳协助胎头旋转、或未及时处理的难产导致。 剖宫产：是处理以上并发症的主要手段。

骨产道异常（11） 中骨盆－出口平面狭窄的处理 轻度狭窄 胎方位异常: 徒手转胎头或低位产钳 继发性宫缩乏力: 缩宫素 明显狭窄: 剖宫产

胎吸助娩 产钳助娩

骨产道异常（12） 几种特殊的异常骨盆 均小骨盆 骨盆畸形: 外伤 佝偻病性骨盆 脊柱后凸和脊柱侧弯骨盆

均小骨盆 各经线均较正常<2cm 或以上

佝偻病性骨盆

骨软化症骨盆 偏斜骨盆

骨产道异常（13） 骨盆异常诊断 病史: 难产史,外伤史 全身查体 腹部查体 (四步触诊、跨耻征实验) ------头盆相与否称 骨盆测量（外测量、内测量） 胎方位 产程

软产道异常 先天畸形 阴道纵隔 阴道横隔 残角子宫 产道软组织瘢痕 下段瘢痕 宫颈瘢痕 阴道和外阴瘢痕 骨盆肿瘤 子宫肌瘤, 卵巢肿瘤和宫颈癌

巨大卵巢肿瘤 子宫肌瘤

胎儿异常 胎方位异常和胎先露异常 巨大儿 胎儿畸形

胎方位 & 胎先露异常 (5-10%) 持续性枕后位和持续性枕横位 头位异常 顶先露和额先露 面先露 臀先露 肩先露 复合先露 头位异常 顶先露和额先露 面先露 臀先露 肩先露 复合先露 Fetal malpresentations are abnormalities of fetal position, presentation, attidude, or lie. The collectively constitute the most common cause of fetal dystocia, occurring in approximately 5-10% of all labors.

复合先露 面先露 持续性枕后位 脑积水儿

异常胎先露 肩先露 额先露 臀先露 面先露

头位难产 颅骨解剖与胎头经线 枕下前囟径 9.3cm 枕额径 11.3cm 枕頦径 13.3cm

头位异常先露 枕先露 顶先露 额先露 面先露 < < 枕頦径 枕下前囟径 枕额径

枕先露的8个方位 注 * 胎先露: 枕先露 * 胎头俯屈良好 正枕前 正枕后 耻骨联合 骶骨 后囟(近枕骨) 前囟

持续性枕后位 & 持续性枕横位 定义: 胎头以枕后位或枕横位于骨盆入口平面衔接,在下降过程中,直至分娩后期仍位于母体骨盆后方或侧方,致分娩发生困难者,称作持续性枕后位或持续性枕横位.

持续性枕后位 & 持续性枕横位 病因 骨产道异常 胎头俯屈不良 宫缩乏力 头盆不称 其他: 前置胎盘等.

持续性枕后位 & 持续性枕横位 诊断 临床表现 腹部查体 肛查和阴道检查 B 超

阴道检查(或肛查)所见 LOT ROT LOP ROP

持续性枕后位 & 枕横位的影响 对分娩-----活跃期和第二产程延长 胎头下降时间延长 对产妇----继发性宫缩乏力 增加手术产率, 侧切伤口延长 及其他软产道撕裂. 增加产后出血可能. 对胎儿----胎儿窘迫 新生儿窒息

持续性枕后位和枕横位的治疗 阴道试产: 无明显产道狭窄和头盆不称 1. 催产素加强宫缩 2. 自然经阴道分娩 (良好的俯屈后) 阴道试产: 无明显产道狭窄和头盆不称 1. 催产素加强宫缩 2. 自然经阴道分娩 (良好的俯屈后) 3. 徒手旋转胎头 4. 出口产钳 (俯屈不良时) 剖宫产: 巨大儿、头盆不称、胎儿窘迫时 molding and caput succedaneum formation falsely indicating a lower descent and may obscure a correct decision about delivery.

胎吸助娩 产钳助娩

高直位和额先露 病因: 处理: 期待 骨盆狭窄 早产 多产 在分娩过程中, 多数自然俯屈为枕先露, 少数继续仰伸成为面先露. 处理: 期待 在分娩过程中, 多数自然俯屈为枕先露, 少数继续仰伸成为面先露. 如果胎儿不是很小, 若不继续俯屈, 很可能发生难产. Brow presentation occurs in approximately 0.06% of deliveries and is associated with the same causative factors as face presentation. In approximately 60% of cases, pelvic contraction, prematurity, and grand multiparity are associated findings. The diagnosis is made by vaginal examination, and management is expectant. Spontaneous conversion occurs in more than 1/3 of all brow presentations. Arrest patterns and uterine inertia are common sequelae because pelvic contraction is so often associated with this presentation. Oxytocin is not recommended, and continuous electronic fetal monitoring is necessary. Liberal use of cesarean section should be made for delivery in cases complicated by a poor outlook for labor. Perinatal mortality rates are low when corrected for congenital anomaly, prematurity, and manipulative vaginal delivery.

高直位 高直后位(枕骶位) 高直前位(枕耻位) Syncypital presentation: also called the military attitude, no flexing or extension of the fetal head is present with respect to the trunk. It is most easily diagnosed by vaginal examination; the bregmatic fontanelle and lambdoid suture are equally prominent. As previously mentioned, spontaneous conversion to face, brow, or vertex presentation is common as labor progresses; therefore, expectant management is recommended. However, cephalopelvic disproportion, uterine inertia, and arrested progress may occur, in which case cesarean section is recommended. 高直后位(枕骶位) 高直前位(枕耻位)

前不均倾 正常位置 后不均倾 前不均倾 矢状缝偏骨盆前部 矢状缝 矢状缝偏骨盆后部 The fetal head engages with its sagittal suture lies on the transverse diameter of the pelvic inlet. It is turns more or less toward the sacrum or symphysis, termed anterior asynclitism 矢状缝偏骨盆前部 矢状缝 矢状缝偏骨盆后部

前不均倾 原因 头盆不称 扁平骨盆 骨盆倾斜度加大 腹壁过分松弛 悬垂腹 治疗 前不均倾一经诊断，立即行剖宫产，不予试产。

面先露: 占总分娩数的0.2% 病因 先天畸形, 如无脑儿、脑积水 头盆不称 早产, 多产 高龄孕妇 骨盆肿瘤 骨盆狭窄 多胎妊娠、羊水过多、巨大儿等 In a face presentation, the fetal head and neck are hyperextended, causing the occiput to come in contact against the upper back of the fetus while lying in a longitudinal axis. The presenting portion of the fetus is the fetal face between the orbital ridges and the chin. this presentation occurs in about 0.2% of all deliveries.

面先露 頦后位 頦前位

面先露 分娩机转 ＊頦后位时，如能转至頦前位有可能经阴道娩出。

面先露 治疗 頦前位 无头盆不称者 可试产，多可经阴道自然分娩 用低位产钳将胎头转至頦前位。 如产程停滞、胎儿窘迫，剖宫产终止分娩 产后新生儿并发症 产道损伤 气管及喉部水肿 新生儿呼吸窘迫 新生儿畸形或肿瘤，如新生儿甲状腺肿，致气管插管困难 With mentum anterior presentation, oxytocin augmentation may be used for arrested labor if cephalopelvic disproportion can be ruled out. Delivery may be accomplished by spontaneous vaginal delivery, use of low forceps to rotate to the mentum anterior position, or cesarean section for arrested labor. There is little or no place for manual flexion of the fetal head or manual rotaion from the mentum posterior position to the mentum anterior position.

＊如頦后位不能转至頦前位，而成为持续性頦后位时，足月活胎不能经阴道娩出，需急行剖宫产终止分娩。 Dangerous The above mechanisms of labor in the term infant can occur only if the mentum is anterior. If the mentum is posterior, the fetal neck is too short to span the length of the maternal sacrum and is already at the point of maximal extension. To deliver, the fetal shoulders must also enter the pelvis, although the head still cannot deliver because it cannot extend further through the symphysis. Mentum posterior positions in average-size fetuses are not deliverable vaginally as they are unable to extend. Arrested labor is typical when spontaneous rotation to the mentum anterior position fails to occur. ＊如頦后位不能转至頦前位，而成为持续性頦后位时，足月活胎不能经阴道娩出，需急行剖宫产终止分娩。

臀先露 占足月分娩的 3% ~ 4% 臀位胎儿先天畸形的发生率高于头位胎儿 围产儿发病率较头位儿高3~8倍 Breech presentation is diagnosed by ultrasound, Leopold's maneuver, or vaginal examination. At term, 3% to 4% of deliveries are in the breech presentation. Because of the higher incidence of congenital anomalies in breech versus vertex presentations in term or preterm gestations, a morphology ultrasound is recommended to rule out this possibility. Breech presentation is always complicated with increased perinatal morbidity, 3-8 folds higher than vertex presentation. Fetal position in breech presentation is determined by using the sacrum as the fetal point of reference to the maternal pelvis. Six positions are recognized: left sacrum transverse, right sacrum transverse left sacrum anterior, left sacrum posterior, right sacrum anterior and right sacrum posterior.

混合臀先露 单纯臀先露 足先露 臀先露 单足先露 双足先露

臀先露的病因 羊水过多、多产和早产 子宫畸形如：双角子宫、子宫纵隔 胎盘位置异常 胎儿异常 (无脑儿, 脑积水, 脊柱裂等), 多胎妊娠或羊水过少 等。 其他: 骨盆狭窄, 前置胎盘, 骨盆肿瘤, 巨大胎儿。 Before 30 weeks, the fetus is small enough in relation to intrauterine volume to rotate from cephalic to breech presentation and back again with relative ease. As gestational age and fetal weight increase, the relative limited intrauterine volume restricts fetal movement. In most cases, the fetus spontaneously assumes the cephalic presentation to better accommodate the bulkier breech pole in the roomier fundal portion of the uterus. Breech presentation occurs when spontaneous version to cephalic presentation is prevented as term approaches or if labor and delivery occur prematurely before cephalic version has taken place.

臀先露的分类 Frank breech presentation: the hips are flexed with extended knees bilaterally. Complete breech presentation: both hips and knees are flexed. Footling breech presentation: one or both legs are extended below the level of the buttocks. 单纯臀先露 足先露 混合臀先露

臀先露的诊断 临床表现 四步触诊: 宫底浮球征 阴道检查和肛诊 B超

臀先露 胎方位 胎手与胎足的鉴别

臀先露 分娩机转 胎头是最硬也最难塑形的部分 在头位分娩时, 胎头的最大经线大与身体的其他部分. 在臀位分娩时,要充分允许后出的胎头经过. 臀先露 分娩机转 胎头是最硬也最难塑形的部分 在头位分娩时, 胎头的最大经线大与身体的其他部分. 在臀位分娩时,要充分允许后出的胎头经过. Among all the fetal parts, the head is the most hard and least compressible. As delivery of the breech occurs, increasingly larger diameters (bitrochanteric, bisacromial, biparietal) of the body enter the pelvis, whereas in cephalic presentation, the largest diameter (biparietal diameter) enters the pelvis first. Particularly in preterm labors, the head is considerably larger than the body and provides a better “dilating wedge” as it passes through the cervix and into the pelvis. The smaller bitrochateric and bisacromial diameters may descend into the pelvis through a partially dilated cervix, but the larger biparietal diameter may be trapped. During spontaneous delivery of an infant in the frank breech position, delivery occurs without assistance and no obstetric maneuvers are applied to the body. The fetus negotiates the maternal pelvis as outlined below, while the operator simply supports the body as it delivers.

臀先露 并发症 对母体 胎膜早破 产程延长、产时并发症增加 感染、损伤和手术产增加 对胎儿 脐带受压、先露、脱垂，致胎儿窘迫 产伤: 小脑幕撕裂, 颅内血肿, 脊髓裂伤, 上肢神经损伤, 骨折, 胸锁乳突肌断裂 6. Maternal fetal complications: Maternal complications: Due to inability of the presenting part to fill the maternal pelvis, either due to prematurity or poor application of the presenting part to the cervix, so that the premature rupture of membrane is more prone to occur. Delayed labor duration and more complex delivery procedures predispose the mother to infection, trauma and operative delivery. 脐带脱垂

臀先露 治疗 孕期 自然转至头位 胸膝卧位 外倒转

臀先露 治疗 产时 自然分娩 -----单纯臀先露 估计胎儿体重<3500g 胎头俯屈良好 无明显先天畸形 经产妇

In complete breech presentation and footling presentation, the fetal feet may descend to the vagina when the cervix is only partially dilated to only 4-5cm. In this case, complete sterilization of the perineum should be applied and the descent of the fetus should be blocked by the obstetrician’s hand during the contraction. In this way, the occurrence of possible entrapment of the aftercoming head and consequent birth injuries may be reduced because of further dilation of the soft birth canal.

As the umbilicus appears at the maternal perineum, the operator places a finger medial to one thigh and then the other, pressing laterally as the fetal pelvis is rotated away from that side by an assistant. Thus, the thigh is externally rotated at the hip and results in flexion of the knee and delivery of one and then the other, leg. The fetal trunk is then wrapped in a towel to support the body. When both scapulae are visible, the body is rotated counterclockwise. The operator locates the right humerus and laterally sweeps the arm across the chest and out the perineum. In a similar fashion, the body is rotated clockwise to deliver the left arm. The head then spontaneously delivers by gently lifting the body upward and applying fundal pressure to maintain flexion of the fetal head. Inappropriate traction on the breech at this point may lead to extension of the fetal head, or entrapment of an arm behind the head (nuchal arm). For delivery of the shoulders and arms, the obstetricians thumbs overlie the sacrum with the fingers around the iliac crests, so that the hands cradle the fetal pelvis.

The Mauriceau-Smellie-Veit maneuver, although not as desirable as Piper's forceps, can prove useful when events progress rapidly, and the obstetrician has inadequate time to apply forceps. The fetal trunk lies astride the obstetrician's forearm, and the obstetrician's middle finger, placed in the fetal mouth, gently flexes the head. The upper hand on the fetal back enables gentle downward and backward traction, while the middle finger of the upper hand pushes upwards on the occiput, encouraging flexion of the head, to avoid damage to the fetal cervical spine.

The operator may elect to manually assist in delivery of the head by performing the Mauriceau-Smellie-Veit maneuver. In this procedure, the index and middle fingers of one of the operator’s hands are applied over the maxilla as the body rests on the palm and forearm of the operator. Two fingers of the operator’s other hand are applied on either side of the neck with gentle downward traction. At the same time, the body is elevated toward the pubic symphysis, allowing for controlled delivery of the mouth, nose, and brow over the perineum.

Application of Piper's forceps to the fetal head, the preferred method of delivering the head. When Piper's forceps have been applied, the fetal trunk, wrapped in a 'breech towel', is supported by one hand, while the other exerts gentle traction on the forceps in the direction of the pelvic axis (arrow).

臀先露 治疗 产时 剖宫产 -----合并先天畸形 足先露 胎儿窘迫 脐带脱垂 估计胎儿体重>3500g且为初产妇 骨盆狭窄可疑

横位 阴道检查时所见

横位 病因 多产 早产 骨盆狭窄 骨盆肿瘤 胎盘位置异常

横位 治疗 孕期 产时 自然转为头位 胸膝卧位 外倒转 产程尚未开始或刚刚开始, 立即行子宫下段剖宫产; 滞产、忽略性横位 警惕病理性缩复环的出现，这是子宫破裂的先兆。 如有严重感染，可在剖宫产同时切除子宫。

异常分娩 小结 多因素相互作用 头盆不称 胎儿异常 骨盆异常 难产 宫缩乏力 梗阻

异常分娩 诊断和处理 产前 产时 早发现胎方位和胎先露异常 胎儿畸形 骨产道和软产道异常 认真记录产程图 准确判断异常分娩的类型,并寻找原因 异常分娩 诊断和处理 产前 早发现胎方位和胎先露异常 胎儿畸形 骨产道和软产道异常 产时 认真记录产程图 准确判断异常分娩的类型,并寻找原因 及时处理产程异常

产科处理流程 明显骨盆狭窄 胎方位异常: 协调性宫缩乏力, 巨大儿, 连体双胎,胎儿窘迫 ( S<+2, 宫颈未开全), 先兆子宫破裂 肩先露 足先露 高直后位 前不均倾 頦后位 协调性宫缩乏力, 无明显头盆不称 巨大儿, 连体双胎,胎儿窘迫 ( S<+2, 宫颈未开全), 先兆子宫破裂 人工破膜 催产素 无进展 有进展 Management：General management 持续性枕后/枕横位 剖宫产 失败 失败 自然阴道分娩 阴道助娩 产钳 徒手转胎头至枕前位 阴道手术产 失败

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