The impact of a routine late third trimester growth scan on the incidence,diagnosis, and management of breech presentation in Oxfordshire,UK: A cohort study

BackgroundBreech presentation at term contributes significantly to cesarean section (CS) rates worldwide. External cephalic version (ECV) is a safe procedure that reduces term breech presentation and associated CS. A principal barrier to ECV is failure to diagnose breech presentation. Failure to diagnose breech presentation also leads to emergency CS or unplanned vaginal breech birth. Recent evidence suggests that undiagnosed breech might be eliminated using a third trimester scan. Our aim was to evaluate the impact of introducing a routine 36-week scan on the incidence of breech presentation and of undiagnosed breech presentation.Methods and findingsWe carried out a population-based cohort study of pregnant women in a single unit covering Oxfordshire, United Kingdom. All women delivering between 37+0 and 42+6 weeks gestational age, with a singleton, nonanomalous fetus over a 4-year period (01 October 2014 to 30 September 2018) were included. The mean maternal age was 31 years, mean BMI 26, 44% were nulliparous, and 21% were of non-white ethnicity. Comparisons between the 2 years before and after introduction of routine 36-week scan were made for 2 primary outcomes of (1) the incidence of breech presentation and (2) undiagnosed breech presentation. Secondary outcomes related to ECV, mode of birth, and perinatal outcomes. Relative risks (RRs) with 95% confidence intervals (CIs) are reported. A total of 27,825 pregnancies were analysed (14,444 before and 13,381 after). A scan after 35+0 weeks was performed in 5,578 (38.6%) before, and 13,251 (99.0%) after (p < 0.001). The incidence of breech presentation at birth did not change significantly (2.6% and 2.7%) (RR 1.02; 95% CI 0.89, 1.18; p = 0.76). The rate of undiagnosed breech before labour reduced, from 22.3% to 4.7% (RR 0.21; 95% CI 0.12, 0.36; p < 0.001). Vaginal breech birth rates fell from 10.3% to 5.3% (RR 0.51; 95% CI 0.30, 0.87; p = 0.01); nonsignificant increases in elective CS rates and decreases in emergency CS rates for breech babies were seen. Neonatal outcomes were not significantly altered. Study limitations include insufficient numbers to detect serious adverse outcomes, that we cannot exclude secular changes over time which may have influenced our results, and that these findings are most applicable where a comprehensive ECV service exists.ConclusionsIn this study, a universal 36-week scan policy was associated with a reduction in the incidence but not elimination of undiagnosed term breech presentation. There was no reduction in the incidence of breech presentation at birth, despite a comprehensive ECV service.

Ibtisam Salim and co-workers report on incidence of breech presentation in pregnant women receiving a 36-week scan.     

Role of pelvimetry in active management of labour.

All cases referred for pelvimetry in 1970-1 and all breech presentations referred for pelvimetry in 1972-4 were reviewed. Indications for pelvimetry fell into four main categories: high head in the antenatal clinic (47-8%); high head in labour (13-9%); breech presentation (20-9%); and previous caesarean section (14-8%). In the first two categories pelvimetry rarely if ever influenced management, and it should not be performed routinely. In breech presentation and cases of caesarean section pelvimetry seemed to be of value, but in the latter group it should be performed puerperally to avoid the known radiation hazard to the fetus. A fairly close correlation between obstetric conjugate and pelvic capacity was shown, which suggested that a 3400-g baby might pass through a pelvis of obstetric conjugate of 10 cm as a cephalic trial of labour, but would need an obstetric conjugate of 11-7 cm for safe vaginal breech delivery.     

Maternal and neonatal individual risks and benefits associated with caesarean delivery: multicentre prospective study

Objective To assess the risks and benefits associated with caesarean delivery compared with vaginal delivery.Design Prospective cohort study within the 2005 WHO global survey on maternal and perinatal health.Setting 410 health facilities in 24 areas in eight randomly selected Latin American countries; 123 were randomly selected and 120 participated and provided dataParticipants 106 546 deliveries reported during the three month study period, with data available for 97 095 (91% coverage).Main outcome measures Maternal, fetal, and neonatal morbidity and mortality associated with intrapartum or elective caesarean delivery, adjusted for clinical, demographic, pregnancy, and institutional characteristics.Results Women undergoing caesarean delivery had an increased risk of severe maternal morbidity compared with women undergoing vaginal delivery (odds ratio 2.0 (95% confidence interval 1.6 to 2.5) for intrapartum caesarean and 2.3 (1.7 to 3.1) for elective caesarean). The risk of antibiotic treatment after delivery for women having either type of caesarean was five times that of women having vaginal deliveries. With cephalic presentation, there was a trend towards a reduced odds ratio for fetal death with elective caesarean, after adjustment for possible confounding variables and gestational age (0.7, 0.4 to 1.0). With breech presentation, caesarean delivery had a large protective effect for fetal death. With cephalic presentation, however, independent of possible confounding variables and gestational age, intrapartum and elective caesarean increased the risk for a stay of seven or more days in neonatal intensive care (2.1 (1.8 to 2.6) and 1.9 (1.6 to 2.3), respectively) and the risk of neonatal mortality up to hospital discharge (1.7 (1.3 to 2.2) and 1.9 (1.5 to 2.6), respectively), which remained higher even after exclusion of all caesarean deliveries for fetal distress. Such increased risk was not seen for breech presentation. Lack of labour was a risk factor for a stay of seven or more days in neonatal intensive care and neonatal mortality up to hospital discharge for babies delivered by elective caesarean delivery, but rupturing of membranes may be protective.Conclusions Caesarean delivery independently reduces overall risk in breech presentations and risk of intrapartum fetal death in cephalic presentations but increases the risk of severe maternal and neonatal morbidity and mortality in cephalic presentations.     

Cesarean section: trends and morbidity.

A review of 1683 cesarean sections performed at one hospital in a 3-year period (1977-79) showed that the cesarean section rate had trebled since 1967-79, the rates being 16.9% and 5.8%. The main indications for cesarean section responsible for this rise were dystocia, breech presentation and a previous cesarean section. AFter the operation 23.3% of received antibiotics. If the cesarean section rate is to fall, the biggest impact can be made by planning vaginal delivery in selected patients with a previous cesarean section and by improving the management of nonprogressive labour.     

Maternal and paternal contribution to intergenerational recurrence of breech delivery: population based cohort study

Objective To investigate intergenerational recurrence of breech delivery, with a hypothesis that both women and men delivered in breech presentation contribute to increased risk of breech delivery in their offspring.Design Population based cohort study for two generations.Setting Data from the medical birth registry of Norway, based on all births in Norway 1967-2004 (2.2 million births).Participants Generational data were provided through linkage by national identification numbers, forming 451 393 mother-offspring units and 295 253 father-offspring units. We included units where both parents and offspring were singletons and offspring were first born, forming 232 704 mother-offspring units and 154 851 father-offspring units for our analyses.Main outcome measure Breech delivery in the second generation.Results Men and women who themselves were delivered in breech presentation had more than twice the risk of breech delivery in their own first pregnancies compared with men and women who had been cephalic presentations (odds ratios 2.2, 95% confidence interval 1.8 to 2.7, and 2.2, 1.9 to 2.5, for men and women, respectively). The strongest risks of recurrence were found for vaginally delivered offspring and were equally strong for men and women. Increased risk of recurrence of breech delivery in offspring was present only for parents delivered at term.Conclusion Intergenerational recurrence risk of breech delivery in offspring was equally high when transmitted through fathers and mothers. It seems reasonable to attribute the observed pattern of familial predisposition to term breech delivery to genetic inheritance, predominantly through the fetus.     

Late results of cesarean and vaginal delivery in cases of breech presentation.

This study compared the subsequent development of children in breech presentation according to the method of their delivery - vaginal or cesarean section. No differences were found between children born vaginally and those born by cesarean section after some labour, except for a larger variability in the outcomes of the latter group. Only 4% of the deliveries were by cesarean section without labour, and when analysed separately the data for this group frequently showed the poorest outcome. Reasons for the observations are suggested, and proposed further research is outlined.     

Fetus presentation and time taken for parturition in Antarctic fur seal, <Emphasis Type="Italic">Arctocephalus gazella</Emphasis>, at Cape Shirreff,Antarctica

We document the influence of fetus orientation in the time invested in the birthing process of Antarctic fur seals at Cape Shirreff, Antarctica. Our results show that breeching was significantly higher than cephalic orientation on the order of 1.5:1. The average duration of the birthing process was 37.26 min, and the average duration considering the fetus orientation was 27.22 and 49.39 min for the cephalic and breech, respectively. The average time was significantly different only in the phase from the appearance of the amniotic-allantoids sac to the complete expulsion of the pup. Possible explanations for this difference are: the friction between the opposite hair direction with the uterus-vaginal wall after the rupture of amnio-allantoid sac during the transit of the fetus in breech position, and/or the fact one or both front flippers would increase the scapular diameter and make the final step of fetus delivery more difficult.     

Hypopituitarism and stalk agenesis: a congenital syndrome worsened by breech delivery?

Thirty-seven patients with idiopathic hypopituitarism, of whom 12 had multiple pituitary hormone deficiencies (MPHD) and 25 isolated growth hormone deficiency (IGHD), were evaluated by magnetic resonance imaging (MRI). Twenty-two of the 37 showed congenital anterior pituitary hypoplasia, stalk agenesis and ectopic posterior pituitary gland at the infundibular recess (group A), while the remaining 15 presented isolated anterior pituitary hypoplasia (group B). Perinatal histories obtained from all patients demonstrated that 18/22 children of group A (81.81%) had histories of adverse perinatal events, with breech presentation in 15 (68.18%). Twelve of 12 children of group A born by breech delivery developed MPHD; 3 born by cesarean section for breech presentation had only IGHD. Patients of group B had also a high incidence of perinatal insults (12/15, 80%), but breech delivery was markedly less frequent (13.33 vs. 68.18% of group A) and responsible for only IGHD. Group B had also higher percentages of maternal spontaneous abortion and low birth weight. Our study suggests that several factors may play a role in the development of growth hormone deficiency. Some patients had severe perinatal insults apparently leading to hypopituitarism. We were able to define by MRI a group of patients with congenital abnormalities, such as anterior pituitary hypoplasia, stalk agenesis and posterior pituitary ectopia, among whom breech presentation was very common. In this group, breech delivery was always followed by MPHD while cesarean or normal delivery in such patients was followed by IGHD only.     

Should all twins be delivered by caesarean section? A preliminary report.

The aim was to analyse the neonatal mortality related to mode of delivery for twins using a population-based registry. In all, 18,125 twins delivered in Sweden between 1991 and 1997, after excluding those with unknown gestational duration, were used to analyse the differences between groups of twins. Results showed the OR for neonatal death, breech vaginal delivery versus caesarean section (all indications) was 1.47 (95% CI 0.99-2.17). The OR at vaginal delivery for neonatal death, twin I in breech versus cephalic presentation was 5.60 (2.62-11.94) and for twin II the corresponding figures were 1.85 (1.03-3.32). Analyses using population-based registries from other countries are needed to confirm or reject the present findings of an increased neonatal mortality for twins in breech presentation delivered vaginally.     

气囊助产在48例臀位分娩中的临床应用

目的探讨气囊助产在臀位分娩中的临床应用价值。方法对我院2005年4月～2009年4月期间48例臀位孕妇施行气囊助产术资料进行回顾性分析。结果48例臀位产妇经阴道臀位助产44例（91.7%）,产后出血量少;在分娩过程中无出头困难发生,产后检查软产道无宫颈裂伤,产后未发生产褥感染。结论气囊助产技术安全可靠,经过正规培训后容易掌握,是一种值得在基层医院进一步推广的新式适宜的助产技术。     

Long-term outcome by method of delivery of fetuses in breech presentation at term: population based follow up.

OBJECTIVE--To compare the long-term outcome of infants delivered in breech presentation at term by intended mode of delivery. DESIGN--A population based comparison of outcomes up to school age. Data obtained from maternity, health visitor, and school medical records and handicap register. SETTING--Grampian region 1981-90. SUBJECTS--1645 infants delivered alive at term after breech presentation. MAIN OUTCOME MEASURES--Handicap, developmental delay, neurological deficit, psychiatric referral. RESULTS--Elective caesarean section was performed in 590 (35.9%) cases. The remainder (1055; 64.1%) were intended vaginal deliveries. Handicap or other health problem was recorded in 269 (19.4%) of 1387 infants for whom records were available. Proportions of elective caesarean sections and intended vaginal deliveries in this group were 37.2% (100 cases) and 62.8% (169) respectively, almost the same as in the total cohort. There were no significant differences between elective caesarean section and planned vaginal delivery in terms of severe handicap or any other outcome measure. Case records were obtained for 23 of 27 infants with severe handicap. 11 (47.8%) were delivered by elective caesarean section. Of these, three had undiagnosed congenital abnormalities and seven were unexplained. Of the 12 (52.2%) planned vaginal deliveries, in only one was handicap possibly attributable to delivery and four cases were unavoidable even if elective caesarean section had been planned. CONCLUSION--In selected cases of breech presentation at term planned vaginal delivery with caesarean section if necessary remains as safe as elective caesarean section in terms of long term handicap. It was not possible to determine whether particular babies would have fared better had they been delivered by elective caesarean section.     

南京某大型医院剖宫产及其影响因素的初步分析

目的:分析某医院剖宫产的现状,初步探讨其影响因素及控制策略。方法:整理分析了南京某大型医院2009年共1411名入院产妇的病历资料,按分娩方式分为自然分娩组(经阴道分娩)和剖宫产组,比较两组产妇的一般信息、身体状况、产时情况等,采用多因素Logistic回归分析了剖宫产的影响因素。结果:该医院2009年度剖宫产产妇为608人,占总产妇的43.09%。剖宫产产妇的年龄和体重明显高于自然分娩产妇(P0.01),既往身体状况相对较差。入院时多无产兆、宫口未开,且产妇宫高、腹围、胎心率明显较高(P0.05或P0.01)。B超检查也显示,羊水异常(过多或过少)、巨大儿、胎位不正(主要为臀位)以及脐带绕颈的比例也明显高于自然分娩产妇(P0.05或P0.01)。多因素Logistic回归分析显示,产妇高龄(35岁)、入院产兆、胎位不正、产妇腹围过大、胎儿窘迫及新生儿超重等皆为剖宫产的独立影响因素。此外发现19.24%的剖宫产产妇无临床指征(即社会因素)。结论:该医院剖宫产的比例不低,要根据影响因素合理选择剖宫产,尤其要有效控制无指征的剖宫产选择,降低剖宫产率。     

Outcome of breech delivery at term.

OBJECTIVE--To compare neonatal mortality and morbidity in term infants presenting by the breech and delivered vaginally or by caesarean section. DESIGN--Population based comparison of outcomes. Data derived from the St Mary''s maternity information system. SETTING--North West Thames Regional Health Authority, 1988-90. SUBJECTS--3447 singleton fetuses presenting by the breech at term. MAIN OUTCOME MEASURES--Intrapartum and neonatal mortality, low Apgar scores, intubation at birth, and admission to special care baby units. RESULTS--After the exclusion of babies with congenital anomalies the incidence of intrapartum and neonatal death associated with vaginal birth was 8/961 (0.83%) compared with 1/2486 (0.03%) in babies born by caesarean section (relative risk 20, 95% confidence interval 2.5 to 163). The numbers of low Apgar scores and neonatal intubation were doubled in babies born vaginally or by emergency caesarean section compared with those delivered by elective operation. CONCLUSIONS--The good neonatal outcome associated with elective caesarean delivery of the term breech fetus may influence the decision of women and their obstetricians about mode of delivery.     

Twin and singleton births in Ghana--a case-control study.

A retrospective study involving 623 twin and 1246 singleton births was conducted to compare the two groups with regard to selected maternal, fetal and labor and delivery characteristics and outcomes. Maternal age and parity were significantly higher for twins. The risks of preterm delivery, arrival in the labor ward in second stage of labor, cesarean births and postpartum haemorrhage were significantly higher in twin than in singleton births. In vaginal deliveries twin mothers were significantly less likely to have had episiotomies or perineal lacerations. There was no difference in the duration of the third stage of labor or in the incidence of retained placentae. Antepartum haemorrhage was a less likely indication for cesarean delivery among twins, while there was no significant difference in the likelihood of severe pre-eclampsia/eclampsia being an indication. Singleton babies were significantly heavier than twins. The incidences of malpresentation, low birth weight, stillbirths and of admission of live births to the neonatal intensive care unit were significantly higher in twins. There was no difference in the rate of instrumental vaginal delivery, or in the route of delivery of fetuses presenting by the breech. There is the need for detailed study of the incidences of antepartum haemorrhage and hypertensive diseases in twin and singleton pregnancies and of the factors determining the mode of delivery when such complications arise. Labor and delivery should also be examined to determine any differences between the two groups, especially in the first and second stages.     

Delivering hydrocephalic fetuses

Detection of fetal hydrocephalus with head enlargement in the third trimester raises questions concerning the extent of the physician's obligations to the fetus and to the mother. Here Strong develops and defends an approach to these questions that he discussed in an earlier essay ("Ethical conflicts between mother and fetus in obstetrics," Clinics in Perinatology 1987 Jun; 14(2): 313-328), dividing the ethical issues involved into two main topics. He first explores under what circumstances a physician is ethically justified in draining fluid from the fetal cranium to reduce head size. This procedure, which usually causes fetal death, facilitates vaginal delivery. A cesarean section, which is less stressful for the fetus, exposes the woman to the risks of surgery. Secondly, Strong applies this discussion to the issue of how the physician should counsel the woman, and what recommendations, if any, the physician should make concerning the method of delivery.     

Relationship between fetal position and stillbirth in the cynomolgus monkeys (Macaca fascicularis): retrospective analysis

Retrospective analyses were made on the relationship between fetal position and stillbirth, using 703 pregnant cynomolgus monkeys. Incidence of the breech position was 59.1% to 12 weeks of gestation. The rate decreased stepwise to 10.4% on the day before delivery. Twenty-one (65.6%) of 32 monkeys who were in the breech position on the day before delivery had stillbirths, whereas only one stillbirth occurred among 275 monkeys whose fetuses were in the cephalic position.     

The effect of delaying childbirth on primary cesarean section rates

Background

The relationship between population trends in delaying childbirth and rising rates of primary cesarean delivery is unclear. The aims of the present study were (1) to characterize the association between maternal age and the outcome of labor, (2) to determine the proportion of the increase in primary cesarean rates that could be attributed to changes in maternal age distribution, and (3) to determine whether the contractility of uterine smooth muscle (myometrium) varied with maternal age.

Methods and Findings

We utilized nationally collected data from Scotland, from 1980 to 2005, and modeled the risk of emergency cesarean section among women delivering a liveborn infant in a cephalic presentation at term. We also studied isolated myometrial strips obtained from 62 women attending for planned cesarean delivery in Cambridge, England, from 2005 to 2007. Among 583,843 eligible nulliparous women, there was a linear increase in the log odds of cesarean delivery with advancing maternal age from 16 y upwards, and this increase was unaffected by adjustment for a range of maternal characteristics (adjusted odds ratio for a 5-y increase 1.49, 95% confidence interval [CI] 1.48–1.51). Increasing maternal age was also associated with a longer duration of labor (0.49 h longer for a 5-y increase in age, 95% CI 0.46–0.51) and an increased risk of operative vaginal birth (adjusted odds ratio for a 5-y increase 1.49, 95% CI 1.48–1.50). Over the period from 1980 to 2005, the cesarean delivery rate among nulliparous women more than doubled and the proportion of women aged 30–34 y increased 3-fold, the proportion aged 35–39 y increased 7-fold, and the proportion aged ≥40 y increased 10-fold. Modeling indicated that if the age distribution had stayed the same over the period of study, 38% of the additional cesarean deliveries would have been avoided. Similar associations were observed in multiparous women. When studied in vitro, increasing maternal age was associated with reduced spontaneous activity and increased likelihood of multiphasic spontaneous myometrial contractions.

Conclusions

Delaying childbirth has significantly contributed to rising rates of intrapartum primary cesarean delivery. The association between increasing maternal age and the risk of intrapartum cesarean delivery is likely to have a biological basis.     

南京某大型医院剖宫产及其影响因素的初步分析

目的：分析某医院剖宫产的现状,初步探讨其影响因素及控制策略。方法：整理分析了南京某大型医院2009年共1411名入院产妇的病历资料,按分娩方式分为自然分娩组（经阴道分娩）和剖宫产组,比较两组产妇的一般信息、身体状况、产时情况等,采用多因素Logistic回归分析了剖宫产的影响因素。结果：该医院2009年度剖宫产产妇为608人,占总产妇的43．09％。剖宫产产妇的年龄和体重明显高于自然分娩产妇（P〈0．01）,既往身体状况相对较差。入院时多无产兆、宫口未开,且产妇宫高、腹围、胎心率明显较高（P〈0．05或P〈0．01）。B超检查也显示,羊水异常（过多或过少）、巨大儿、胎位不正（主要为臀位）以及脐带绕颈的比例也明显高于自然分娩产妇（P〈0．05或P〈0．01）。多因素Logistic回归分析显示,产妇高龄（〉35岁）、入院产兆、胎位不正、产妇腹围过大、胎儿窘迫及新生儿超重等皆为剖宫产的独立影响因素。此外发现19．24％的剖宫产产妇无临床指征（即社会因素）。结论：该医院剖宫产的比例不低,要根据影响因素合理选择剖宫产,尤其要有效控制无指征的剖宫产选择,降低剖宫产率。     

经会阴三维超声评价不同分娩方式初产妇肛门括约肌复合体和盆膈裂孔的临床应用价值

摘要 目的：探讨经会阴三维超声在不同分娩方式初产妇肛门括约肌复合体（ASC）和盆膈裂孔（PH）影响的评估价值。方法：选择2017年1月～2019年12月我院进行分娩的初产妇150例,按照分娩方式分成阴道分娩组71例,剖宫产组79例,比较两组基线资料。对所有受试者均实施经会阴三维超声检查,比较两组缩肛动作下肛门内括约肌（IAS）远端、中端及远端平面厚度,肛门外括约肌（EAS）远端平面及耻骨直肠肌（PRM）中端平面厚度,分娩前、产后6周、产后3个月PH左右径、PH前后径以及PH面积。结果：两组孕妇年龄、孕周及体质指数比较无差异（P＞0.05）,阴道分娩组IAS近端6点钟方向、12点钟方向平面厚度以及IAS中端、12点钟方向平面厚度均小于剖宫产组（P＜0.05）。阴道分娩组EAS远端12点钟方向平面厚度小于剖宫产组（P＜0.05）。阴道分娩组产后6周的PH左右径大于剖宫产组（P＜0.05）。阴道分娩组产后6周的PH前后径大于剖宫产组（P＜0.05）。阴道分娩组产后6周的pH面积大于剖宫产组（P＜0.05）。结论：经会阴三维超声可有效评估初产妇ASC和PH的影响情况,分娩会对初产妇ASC和PH产生影响,阴道分娩的初产妇产后存在明显的ASC厚度减小和PH增大现象。