臀位矫正技术的应用及研究进展

正臀位是产科异常胎位中最常见的一种,臀位发生率占妊娠足月分娩总数的3%~4%[1]。由于臀位先露部分不规则,对前羊膜囊压力不均,易致胎膜早破、脐带脱垂,脐带受压导致胎儿窘迫甚至死亡。此外,臀位阴道分娩易发生后出头困难,常发生新生儿脊柱损伤、臂丛神经损伤、颅内出血等,也可导致产妇软产道撕裂、产后出血等[2],臀位围产儿发病率和死亡率明显高于头位[3]。因此,目前臀位分娩方式大多选择剖宫产来避免臀位阴道分娩并发症[4]。据统计,美国臀位剖宫产率从1970年     

显性脐带脱垂77例临床分析

1977年至1991年15年间,我院分娩总数28420次,共发生显性脐带脱垂77例,发生率为0.27%,围产儿病死率为223.7‰.脐带脱垂的原因主要为胎位异常,以臀位足先露较多,其次为胎头高浮,脐带过长,低体重儿等.处理原则为:一旦发生脐带脱垂,应立即取臀高位,经阴道上推先露部,如不能立即分娩,确认胎儿尚存活者,即刻就地行剖宫产术,获活产儿成功率较高.对宫口已开全具备经阴道分娩条件者,立即阴道助产分娩比等待自然分娩围产儿结局要好.     

臀位分娩方式及助产术问题

臀位(臀先露)是最常见的异常胎位,其分娩方式的选择存在很大争议,目前尚无统一标准。应在遵循母儿安全原则基础上,采取个体化处理,最大程度减少臀位分娩并发症。臀位助产必须对孕妇和胎儿进行充分的产前评估,助产人员必须熟练掌握臀位分娩机制,正确处理分娩过程中可能出现的异常情况,以减少母儿并发症。     

臀位分娩:窘迫的原因

尽管国家卫生研究院(National Institutes of Health,NIH)一致通过的报告推荐减少剖腹产手术,剖腹产率仍在持续增长。即使资料明确证实剖腹产并不比阴道分娩有利,许多作者仍不强调剖腹产指征,主张臀位时常规行剖腹产术。本文对产科学文献进行评论性分析,欲解答臀位时剖腹产是否优于阴道分娩。 Seeds等总结了臀位及头位两种分娩结果,提出与臀位相关的危险有:早产(16～33%)、严重畸形(6～18%)、产伤(正常产危险的13倍)、脐带脱垂(正常产危险的5～20倍)、宫内窒息(正常产危险的3～8倍)、脊柱韧带损伤和脊柱偏斜(21%)、头过度仰伸(5%)、后出儿头受阻(8.8%)。回顾已发表的资料,观察到不纯臀先露围产期     

臀位助产

臀位是产科最常见的异常胎位之一,发生率约占分娩总数的3～5%。臀位阴道分娩时,由于易发生脐带脱垂和后出胎头困难,围产儿死亡率比头位高3倍,产伤所致各种障碍为头位产的12倍。对臀位的处理已成为大家关心的问题,十多年来由于加强臀位的管理,适当放宽剖宫产指征,围产儿的死亡率已明显下降。臀位产的并发症一、胎膜早破臀位先露部小,软而不规则,不能与子宫下段紧贴,容易发生胎膜早破。除增加母儿的     

臀位分娩方式的选择

臀位的分娩方式通常有臀位助产、臀位牵引,剖宫产与穿颅术。臀位分娩方式的选择与围产儿损伤率及死亡率的关系密切.随着围产医学的发展,总结过去臀位阴道分娩并发脐带脱垂,后出胎头分娩困难以及围产儿损伤率和死亡率比头位阴道分娩高出数倍等情况,而引起普遍重视。近年来国内外许多作者报道主张提高臀位剖宫产率,以降低围产儿损伤率与死亡率。     

臀位的分娩机转

臀位分娩的特点及可能产生的问题一、娩头困难 1.臀小于肩,肩小于头,后出的头既大且硬。臀位分娩与头位不同,头先露时,只要大而硬的头部通过产道之后,胎肩和胎臀便可顺利地从已被胎头充分扩张的产道娩出;而臀位则不同,最先以小而软的臀为先露入盆,在产道尚未完全扩张,甚至宫口尚未开全时,足膝或臀部即可通过,结果必然导致胎肩尤其是胎头娩出困难。     

臀位产的围产儿死亡率

本文根据驻北京部队六个医院(解放军总医院、北京军区总医院、海军总医院、空军总医院,解放军309医院和解放军304医院)1959～1978年20年间,58,407次分娩资料,分析讨论臀位产围产儿死亡原因和臀先露分娩方式及臀位产分娩过程的特点,以探讨如何降低围产儿死亡率。资料分析一、本组调查了58407例次分娩,其中臀位产1703例次,其发生率为2.9％,低于国内外文献报道。     

胎儿-骨盆指数在阴道臀位分娩过程中2002063预测胎儿骨盆不称的作用

迄今为止 ,产科医师对于足月妊娠臀先露分娩过程的处理仍感棘手 ,问题的焦点是骨盆与后出胎头的关系。不幸的是臀位阴道分娩出现头盆不称的现象时有发生 ,严重威胁着胎儿和产妇的安全。研究的目的在于通过测量胎儿 -骨盆指数来预测臀位阴道分娩过程中胎儿 -骨盆不称和胎头 -骨盆不称。研究包括 98例产前或处于分娩潜伏期的产妇 ,有明确的剖宫产指征者除外 (包括巨大儿、骨盆狭窄、前次剖宫产史和急性胎儿宫内窘迫者 )。对所有产妇均行 X线骨盆测量 ,并用超声测量胎儿大小。产妇左侧卧位 ,X线的焦点定位于大转子 ,测量骨盆的入口和中骨盆的…     

臀位婴儿死亡率与分娩方式的关系

为探讨臀位婴儿死亡率和分娩方式的关系,作者统计分析了1976～1977两年间分娩的38,186例中臀位胎儿出生体重在1,000g 以上的1,593例,经计算机贮存的资料认为:臀先露阴道分娩和剖腹产的新生儿死亡率(尽管数字很少),二者无统计学差异(P>0.3)。胎儿围产期死亡依统一标准分为产前死亡(即胎儿死在产前或胎心音在分娩开始前消失)、产时死亡(即胎心音在分娩期或临产前可听到但出生婴儿为死产者)及新生儿死亡。本文将新生儿出生体重>1,000g 者分为1,000～1,499g、1,500～1,999g,2,000～2,499g 和>2,500g 四组,     

Breech delivery

Fetuses that present by the breech are at increased risk of trauma and hypoxia during delivery. The threshold for Caesarean section for breech presentation had been low for several years. The result of the term breech trial confirms that planned Caesarean section is the best method of delivering the singleton frank or complete breech at term. The best mode of delivery for the pre-term breech is less clear. Vaginal breech delivery will be unavoidable in certain circumstances and it is therefore important to be adept with the techniques of vaginal breech delivery. The atraumatic technique of delivery of the baby presenting by the breech at times of Caesarean section is similar to that of assisted vaginal breech delivery. The number of vaginal breech deliveries is falling, and regular teaching using video clips or practising with mannequins will be necessary to preserve the skills of vaginal breech delivery.     

ACOG Committee Opinion No. 340. Mode of term singleton breech delivery

In light of recent studies that further clarify the long-term risks of vaginal breech delivery, the American College of Obstetricians and Gynecologists recommends that the decision regarding mode of delivery should depend on the experience of the health care provider Cesarean delivery will be the preferred mode for most physicians because of the diminish-ing expertise in vaginal breech delivery. Planned vaginal delivery of a term singleton breech fetus may be reasonable under hospital-specific protocol guidelines for both eligibility and labor management. Before a vaginal breech delivery is planned, women should be informed that the risk of peri-natal or neonatal mortality or short-term serious neonatal morbidity may be higher than if a cesarean delivery is planned, and the patient's informed con-sent should be documented.     

Do any indications remain for vaginal delivery in breech presentation?

The choice of the mode of delivery in breech presentations is still controversed, particularly in the primipara and in premature delivery. From the study of 277 cases of single pregnancy with a live baby in podalic position the authors analyze the indications for the mode of delivery as well as the foetal results. After 37 complete weeks of amenorrhea, labour was induced in 126 patients out of 248. 96 had a vaginal delivery. The labour comprises a certain number of risks, but gives the same results as the caesarian section. The primiparity does not seem to be a risk factor. Before 37 complete weeks of amenorrhoea, 7 babies were born by vaginal delivery and 22 by caesarian section. In case of foetal distress, the caesarian section decided too late does not avoid an unfavourable evolution, particularly in the very premature baby. Therefore, the indications for caesarian sections must be extremely large and decided without delay particularly before 32 complete weeks of amenorrhea.     

Moderate neonatal morbidity after vaginal term breech delivery.

OBJECTIVE: Comparison of the results of term breech births in our clinic with the Term Breech Trial (TBT). MATERIAL AND METHODS: During the investigation period prospective data were collected on all deliveries of a term baby in breech presentation. Some pregnant women were included in the TBT and randomized in a planned cesarean section (CS)-group and a planned vaginal birth (VB)-group. The remaining non-randomized women were divided into a primary CS-group and a started VB-group. Neonatal and maternal mortality and morbidity were analyzed retrospectively, according to the intended mode of delivery. RESULTS: Neonatal or maternal mortality occurred in none of the groups. Neither in the randomized group nor in the non-randomized group were significant differences in serious neonatal and maternal morbidity observed between the intended cesarean section-group and the group that started vaginal delivery. However, in the non-randomized group, moderate neonatal morbidity was significantly lower in the primary CS-group than in the started VB-group. CONCLUSION: The differences in moderate neonatal morbidity support the conclusion of the TBT, that primary cesarean section may be safer for the term breech baby than a trial of vaginal labor.     

Management of breech presentation in areas with high prevalence of HIV infection.

OBJECTIVE: To provide recommendations for the management of breech presentation in areas of high prevalence of human immunodeficiency virus (HIV) infection. METHOD: Review of relevant literature. RESULTS: Studies show that elective cesarean section (CS) is safer than vaginal delivery for breech presentation, external cephalic version (ECV) at term increases the chance of vaginal cephalic delivery. Although there are no studies of the risk of mother-to-child transmission of HIV from ECV, indirect evidence suggests that any increased risk is likely to be very small. RECOMMENDATIONS: Where CS is available and safe, HIV-positive women, or women who might be at risk of HIV, with a fetus at term with breech presentation, should be offered elective CS to reduce the risks of both vaginal breech delivery and mother-to-child HIV infection. HIV-negative women can be offered ECV at term to try to avoid CS. Where women do not have access to a safe CS, or prefer vaginal delivery, the benefit for both mother and child of attempting ECV at term is likely to outweigh the theoretical, very small, risk of facilitating HIV transmission.     

Evolving Evidence Since the Term Breech Trial: Canadian Response,European Dissent,and Potential Solutions

ObjectivesWe wished to gain insight into Canadian hospital policy changes between 2000 and 2007 in response to (1) the initial results of the Term Breech Trial suggesting delivery by Caesarean section was preferable for term breech presentation, and (2) the trial’s two-year follow-up and other research and commentary suggesting that risks associated with vaginal breech delivery and delivery by Caesarean section were similar. We also wished to determine the availability of vaginal breech delivery and the feasibility of establishing breech clinics and on-call squads, and whether these could include midwives.MethodsIn 2006, we sent surveys to the 30 largest maternity centres in Canada asking about their changes in practice in response to results of the initial Term Breech Trial and the subsequent two-year follow-up and the possibility of establishing breech clinics and on-call delivery squads and whether they could include midwives.ResultsOf the 30 surveys sent, responses were received from 20 maternity centres in six provinces. Hospitals were almost five times more likely to adopt a policy of requiring Caesarean section for breech delivery when current evidence suggested that it decreased risk for the neonate than they were to reintroduce the option of vaginal breech delivery when it did not. A breech clinic was considered possible, feasible, and desirable by only one centre, and forming a breech squad was similarly regarded by only two hospitals; 70% of respondents, however, did not entirely dismiss either possibility.ConclusionsThe weight of epidemiologic evidence does not support the practice developed in Canadian hospitals since the Term Breech Trial that recommends delivery by Caesarean section for all breech presentations. Obstetric and midwifery bodies will require creative strategies to make clinical practice consistent with current national and international evidence.     

Obstetric trainees' experience in vaginal breech delivery: implications for future practice

OBJECTIVE: To determine whether trainee obstetricians intend to offer vaginal breech delivery once they become certified as specialists and to quantify their experience in vaginal breech delivery. METHODS: This was an anonymous postal survey of all Australian trainee obstetricians. The survey inquired about experience with, confidence in, and intentions regarding planned vaginal breech delivery after trainees' certification as specialists. RESULTS: Surveys were sent to all 303 Australian registered trainee obstetricians. The response rate was 65%. Experience in vaginal breech delivery increased with year of training, from a median of one delivery for first-year trainees to a median of 12 deliveries for final-year trainees. Although 53% of final-year trainees reported feeling confident with vaginal breech delivery, only 11% reported an intention to offer planned vaginal breech delivery at term as a specialist. CONCLUSION: Few of the next generation of specialist obstetricians plan to offer vaginal breech delivery to their patients.     

Influence of presentation on neonatal outcome of vaginally delivered low birthweight infants. A matched pair analysis

Neonatal outcome of 30 low birthweight (800 to 2000 g) breech infants delivered vaginally was compared with a matched sample of vaginally delivered vertex infants. Using a multiple regression analysis, presentation was found to be significantly related only to the Apgar score at 1 minute. No effect of presentation was found on Apgar score at 5 minutes, length of stay in the nursery, need for ventilatory support, or incidence of neonatal death, seizures, or intracranial hemorrhage. Thus, vaginal delivery of low birthweight breech fetuses was associated with short-term infant outcomes comparable to those of similar fetuses delivered vaginally from vertex presentations. The findings suggest that prevailing assumptions about the risks of premature breech vaginal delivery need to be evaluated critically.     

Good perinatal outcome in selective vaginal breech delivery at term

BACKGROUND AND AIM: To compare perinatal outcome in groups of planned vaginal breech delivery, elective cesarean section with the fetus in breech presentation, and planned vaginal delivery with the fetus in cephalic presentation in a university hospital with a tradition of managing breech deliveries by the vaginal route. METHODS: A cohort study from a 7-year period 1995-2002, including 590 planned vaginal deliveries with a term (> 37 weeks) singleton fetus in breech presentation, 396 elective cesarean sections with a term singleton fetus in breech presentation, and 590 control women intending vaginal delivery with a singleton term fetus in cephalic presentation. RESULTS: The Apgar scores were lower in the group of planned vaginal breech delivery, but in other outcome measures there were no significant intergroup differences. The overall neonatal morbidity was small (1.2% vs. 0.5% vs. 0.3% in the respective study groups) if compared to a recently published randomized multicenter study. CONCLUSIONS: Selective vaginal breech deliveries may be safely undertaken in units having a tradition of vaginal breech deliveries.     

Outcomes of term vaginal breech delivery

In December 2001, the American College of Obstetricians and Gynecologists revised their recommendations for breech delivery. These recommendations acknowledge that although a planned vaginal delivery may no longer be appropriate, there are instances in which vaginal breech delivery is inevitable. Moreover, there continues to be patients who for any number of reasons will choose vaginal over cesarean delivery when faced with a fetus in the breech presentation. We sought to review maternal and fetal outcomes in such circumstances when vaginal breech delivery occurs, and compare these outcomes to elective cesarean deliveries for breech presentation. We performed a retrospective review of all singleton breech deliveries at our county hospital from January 2002 through June 2003. We reviewed maternal age, ethnicity, gestational age, gravity, parity, birthweight, mode of delivery, Apgar scores, umbilical arterial blood gases, and maternal and infant complications of both cesarean deliveries and vaginal breech deliveries. Univariate and logistic regression statistical analyses were performed with NCSS software. We had a total of 150 term breech deliveries with gestational ages between 37 and 42 weeks. Of these, 41 were vaginal breech and 109 were cesarean deliveries. Greater than 95% of patients are of Hispanic origin. There were no statistically significant differences in maternal age, ethnicity, gravity, or gestational age. Mean birthweight was significantly lower and parity was significantly higher in the vaginal delivery group. There was also a higher proportion of patients who underwent labor induction/augmentation in the vaginal group. We found no differences in the outcomes of 5-minute Apgar scores, umbilical arterial blood gas values, neonatal intensive care unit admissions, deaths or maternal/fetal complications reported between the two groups. Mean umbilical arterial blood gas values were greater than 7.18 in both groups. Vaginal breech delivery cannot always be avoided. Moreover, at our county hospital several patients continue to choose vaginal breech delivery. Our data would suggest that vaginal breech delivery remains a viable option in selected patients.