Method of Delivery and Neonatal Mortality among Very Low Birth Weight Infants in the United States

OBJECTIVE: To examine the association between method of delivery (primary cesarean section vs. vaginal) and neonatal mortality risk (as well as causes of death) among very low-birth weight first-born infants in the United States. More specifically, to examine this association separately for breech/malpresenting and vertex-presenting infants, while adjusting for selected maternal characteristics, and pregnancy, labor and delivery complications. METHODS: The study population was derived from the 1995-1998 birth cohort linked birth/infant death data sets. Binary and multinomial logit regression analyses were performed to assess the relationship in four very low-birth weight categories. RESULTS: Among breech/malpresenting neonates, compared to those delivered vaginally, infants delivered by a primary cesarean section had significantly lower adjusted relative risks of death for all very low-birth weight categories and the decrease in relative risk tended to be larger with each increasing birth weight category. However, for vertex-presenting neonates, results are mixed, suggesting decreased relative mortality risks associated with primary cesarean section, which were significant for 500-749 g, not significant for 750-999 g, and barely significant for 1,000-1,249 g. In contrast, for vertex-presenting neonates weighing 1,250-1,499 g, there was a significantly increased adjusted relative risk associated with primary cesarean section. Differences in cause-specific neonatal mortality by method of delivery and presentation status were also discussed. CONCLUSIONS: Primary cesarean section appears to be associated with decreased neonatal mortality risks in each very low-birth weight category for breech/malpresenting infants, but results are mixed for vertex-presenting infants. Causal inferences should be avoided because this was an observational study by design.     

Birthweight-specific infant mortality risk in cesarean section.

The role of cesarean section in improving infant survival has not been clearly documented. We calculated birthweight- and race-specific infant, neonatal, and postneonatal mortality risks by method of delivery for single- and multiple-delivery infants, using data from 14 states, reported to the Centers for Disease Control through the 1980 National Infant Mortality Surveillance project. For single-delivery infants, the risk of death for infants delivered by cesarean section was 1.6 times higher than for infants delivered vaginally among blacks and 1.2 times higher among whites. The risk was 1.7 times higher during the neonatal period and 1.2 times higher during the postneonatal period. For infants with birthweight less than 1,000 grams, the risk of death was lower when infants were delivered by cesarean section. The risk of death among multiple-delivery infants born by cesarean section was significantly lower than for those born vaginally. This analysis demonstrates that, unlike other birthweight categories, infants with a very low birthweight may have better outcomes if delivered by cesarean section. However, we cannot recommend the routine use of cesarean section for delivering very low birthweight infants. Further studies are needed to determine survival of such infants after controlling for maternal and infant conditions that prompted delivery by cesarean section.     

Obstetric delivery and risk of neonatal mortality in Goiânia in 2000, Brazil

OBJECTIVE: To determine factors associated to vaginal delivery and increased neonatal mortality in cohort studies of newborns. METHODS: A retrospective cohort study was carried out using linkage data from the Information System on Live Births and Mortality Data System database, which included all newborns in Goiania for the year 2000. A stratified analysis of delivery routes and maternity hospitals by risk factors of neonatal mortality was conducted through the calculation of relative risk at a 5% significance level. Statistical analyses were carried out using the Chi-square test at a 5% significance level. RESULTS: Vaginal deliveries were more commonly seen than cesarean sections in situations where there was an increased risk of neonatal mortality. Public hospitals, where vaginal deliveries predominated, were sought by the majority of those pregnant women with an increased risk of neonatal mortality. Private hospitals, not affiliated to the public-funded Brazilian Healthcare System (SUS) and where the incidence of cesarean section was as high as 84.9%, opted for vaginal delivery in situations of greater risk, such as extreme prematurity and very-low-birth-weight infants. CONCLUSIONS: The association between vaginal delivery and increase neonatal mortality resulted from a selection bias due to the distribution of pregnant women in the hospital network. In addition, this selection bias also resulted from an almost universal preference for cesarean sections in low-risk pregnancies as opposed to vaginal delivery for pregnancies with an increased risk of neonatal mortality.     

Association of electronic fetal monitoring during labor with cesarean section rate and with neonatal morbidity and mortality.

Data from the 1980 National Natality Survey by the National Center for Health Statistics were used to assess the relation of electronic fetal monitoring (EFM) during labor with cesarean section rates and neonatal morbidity and mortality. In univariate analyses, EFM was associated with higher cesarean section rates, lower five-minute Apgar scores, and a higher rate of respiratory distress. Logistic regression analysis controlling for other risk factors for poor neonatal outcome indicated that the association of EFM with higher cesarean section rates persisted (odds ratio 1.45, 95% CI 1.16, 1.81), except in certain pregnancies at very high risk for cesarean section. EFM was associated with an Apgar score less than 6 at five minutes only if delivery was by cesarean section. EFM was not found to be independently associated with respiratory distress. Neither univariate nor multivariate analyses found an association of EFM with neonatal mortality. These results suggest that EFM may identify hypoxic infants, who are frequently delivered by cesarean section. The lack of association of EFM with beneficial neonatal outcomes is consistent either with lack of effect of EFM or with uncontrolled selection bias.     

臀位分娩方式的变化对新生儿预后的影响

目的:探讨10年中臀位分娩方式变化对新生儿预后的影响,指导临床选择合适的分娩方式,正确掌握臀位阴道助产术。方法:对本院1989年1月~1998年12月单胎臀位分娩686例分3个阶段进行回顾性分析。结果:10年间单胎臀位的剖宫产率上升,差异有显著性(P<0.01),第1阶段新生儿窒息率及死亡率较高(P<0.01),第2、3阶段无差异(P>0.05)。臀位早产发生率较同期头位高(P<0.01),早产儿死亡占臀位产儿死亡的3/4。结论:适当放宽单胎臀先露剖宫产指征可以提高围产儿质量,但无限制地提高剖宫产率不能无限度地降低围产儿死亡率;臀位阴道助产是可行的,关键是掌握适应症及助产技术和操作规程。     

Incidence of and indications for cesarean sections in the Quebec, Canada region 1973 and 1979

This study describes the frequency of cesarean sections and their indications in eleven hospitals located in the Quebec City area, in 1973 and 1979. Information on cesarean sections was abstracted from hospital records. Birth certificates provide the information on all deliveries. From 1973 to 1979, the cesarean delivery rate increased from 7.9 to 13.6 per 100 deliveries. Repeat cesarean sections account for 40.4% of this increase, while primary cesarean sections for dystocia, breech presentation and fetal distress explain respectively 21.1%, 21.1% and 12.3% of the rise. Prolonged labour, prolonged rupture of membranes, general anesthesia and pre-term repeat cesarean section were observed less frequently among cesarean sections in 1979. Moreover, Apgar scores were higher in 1979 than in 1973.     

958例高龄初产妇妊娠结局分析

目的:了解高龄初产妇的妊娠结局。方法:对958例35岁以上高龄初产妇的相关资料进行回顾性分析,并与同期分娩的非高龄初产妇1050例进行对照研究。结果:高龄初产妇前置胎盘、妊娠高血压疾病、慢性高血压合并妊娠、妊娠期糖尿病、IGT、贫血、子宫肌瘤合并妊娠、剖宫产率显著高于非高龄组,产钳术占阴道分娩的比例显著高于非高龄组,顺产率显著低于非高龄组,而胎儿窘迫的发生率非高龄组显著高于高龄组。高龄组分娩孕周显著小于非高龄组,两组的早产率、新生儿窒息、转儿科率均无显著性差异;高龄组的新生儿畸形率比非高龄组有增高趋势,但无统计学差异;高龄组围产儿死亡和晚期流产率显著高于非高龄组,新生儿体重显著低于非高龄组。结论:高龄孕妇的妊娠合并症和并发症明显增多,晚期流产率高,剖宫产率高,阴道分娩者中助产率高,围产儿结局稍差,应加强围产保健以减少合并症和并发症的发生率。     

分娩方式与产程对新生儿窒息的影响

目的 探讨分娩方式与产程对新生儿窒息的影响,降低新生儿窒息发生率和死亡率.方法 对141例新生儿窒息的因素以及产程、分娩方式进行对比分析.结果 ①臀位助产、臀位牵引、胎头吸引术、剖宫产术的新生儿窒息率经统计学处理明显高于自然分娩率(P＜0.01);②滞产、第二产程延长者新生儿窒息率经统计学处理明显高于正常产程与第二产程正常的新生儿窒息率(P＜0.01).结论 对胎位不正、滞产、第二产程延长者,产时适时选择正确的分娩方式极为重要.     

Time of birth and risk of intrapartum and early neonatal death

BACKGROUND: Previous studies have found that infants born at night and during weekends and holidays have an increased risk of perinatal mortality. However, these associations may be confounded by the distribution of high-risk deliveries according to time of birth. METHODS: We undertook a population-based cohort study of 694,888 singleton births without elective cesarean section in Sweden between 1991 and 1997. We estimated relative risks of intrapartum and early neonatal death according to the hour, day and month of delivery. Estimated risk ratios were adjusted for gestational age, birth weight for gestational age, malformations, induction of labor, breech presentations and year of birth. RESULTS: Infants of high-risk deliveries were more often delivered during daytime (8:00 am to 7:59 pm). Compared with infants born during daytime, infants born at night were at increased risk of early neonatal death (adjusted risk ratio = 1.28; 95% confidence interval = 1.13-1.46), but not intrapartum death (1.05; 0.71-1.54). If this association is causal, 12% of early neonatal deaths can be attributed to the increased risk among nighttime births. There was no association of weekend or holiday births with risks of intrapartum or early neonatal death. CONCLUSIONS: Infants born at night may be at increased risk of early neonatal death.     

3447例早期足月产临床分析

目的分析早期足月产的原因、相关因素、不同分娩孕周及妊娠结局。方法将2009年~2013年在无锡市人民医院住院分娩的3 447例早期足月产病例按分娩孕周分为37周和38周两组,对发生原因、不同分娩孕周及新生儿结局进行回顾性分析。结果 (1)早期足月产发生率为28.31%(3 447/12 176)。(2)择期剖宫产原因排在前五位的是社会因素、瘢痕子宫、胎儿窘迫、羊水过少、胎儿臀位。(3)37周组新生儿呼吸系统发病率(4.52%)高于38周新生儿(2.39%),差异有统计学意义(P0.05),其新生儿窒息率两组比较差异无统计学意义(P0.05)。(4)37周择期剖宫产的新生儿呼吸系统发病率(6.32%)高于同期阴道分娩儿(2.37%),差异有统计学意义(P0.05),其新生儿窒息率比较差异无统计学意义(P0.05);38周择期剖宫产新生儿呼吸系统发病率(2.42%)高于同期阴道分娩儿(1.52%),差异有统计学意义(P0.05),其新生儿窒息率比较,差异无统计学意义(P0.05)。结论 37周新生儿呼吸系统发病率高于38周分娩新生儿,择期剖宫产新生儿呼吸系统发病率高于阴道分娩儿,临床工作中应把握择期剖宫产时机,预防不必要的早期足月产。     

The epidemiology of perinatal mortality in multiple births.

The epidemiology of perinatal mortality in multiple pregnancies was investigated from data on 16,831 multiple births from New York City''s computerized vital records for 1978-1984. Twins had a sixfold higher rate of neonatal death and a threefold higher rate of fetal death during labor than had singleton infants. Much of this excess mortality can be explained by the lower birthweight distribution in twins: between 1,001 and 2,500 grams twins had birthweight-specific death rates equivalent to or substantially less than singletons. However, in infants of normal birthweights, twins had more than three times the mortality risk of singletons. For twins in vertex presentation between 1,001 and 3,000 grams, cesarean section did not appreciably reduce neonatal mortality risk. For twins in vertex presentation who weighted more than 3,000 grams the neonatal mortality rate was more than four times higher in vaginal deliveries than in cesarean sections (exact p = 0.034). Efforts to prevent intrapartum and neonatal mortality in multiple births should aim at reducing the incidence of low birthweight twins. More research is needed on the etiology of perinatal problems in normal birthweight twins (greater than or equal to 2,501 grams), especially on the effects of different modes of delivery.     

Delivery by Cesarean section and early childhood respiratory symptoms and disorders: the Norwegian mother and child cohort study

Studies have indicated that children delivered by cesarean section are at an increased risk of developing wheezing and asthma. This could be the result of an altered immune system development due to delayed gut colonization or of increased neonatal respiratory morbidity. The authors examined the associations between delivery by cesarean section and the development of wheezing, asthma, and recurrent lower respiratory tract infections in children up to 36 months of age among 37,171 children in the Norwegian Mother and Child Cohort Study. Generalized linear models were used in the multivariable analysis. Children delivered by cesarean section had an increased likelihood of current asthma at 36 months of age (relative risk = 1.17, 95% confidence interval: 1.03, 1.32), and the association was stronger among children of nonatopic mothers (relative risk = 1.33, 95% confidence interval: 1.12, 1.58). No increased risk of wheezing or recurrent lower respiratory tract infections was seen among children delivered by cesarean section. Findings were similar among children delivered by acute and elective cesarean section. In conclusion, children delivered by cesarean section may have an increased risk of current asthma at 36 months, but residual confounding cannot be excluded. In future prospective studies, investigators should reexamine this association in different age groups.     

云南省8家医院剖宫产率及其影响因素

目的探讨剖宫产率及其影响因素。方法对我省8家医院1988~2006年的所有住院分娩的产妇资料进行搜集、整理和分析。结果平均剖宫产率为39.2%,呈逐年上升趋势(P<0.025)。1988年剖宫产率,城市为26.5%,农村为11.3%。2006年剖宫产率,城市为41.0%,农村为30.3%。城市剖宫产率高于农村(P<0.01),但农村剖宫产率上升较快,2006年与2002年相比上升了3.2倍。影响剖宫产率的因素有城乡、婴儿出生体重、孕次、产次、年份、高龄初产等。结论剖宫产率呈逐年上升趋势,导致剖宫产率升高有医学和非医学的原因。     

臀位外倒转术对足月单胎臀位产妇外倒转成功率及妊娠结局的影响

目的探讨臀位外倒转术对足月单胎臀位产妇外倒转成功率及妊娠结局的影响。方法选择2017年1月至2019年4月我院收治的60例足月单胎臀位产妇,随机分为两组各30例。研究组行臀位外倒转术,对照组行膝胸卧位。对比两组的臀位矫正成功率、分娩方式及并发症情况。结果研究组的臀位矫正成功率为73.33%,高于对照组的43.33%(P<0.05)。研究组的阴道分娩率为56.67%,高于对照组的20.00%(P<0.05)。研究组的胎膜早破发生率为6.67%,低于对照组的30.00%(P<0.05);两组的脐带绕颈、新生儿窒息发生率比较差异无统计学意义(P>0.05)。结论臀位外倒转术可有效提高足月单胎产妇臀位矫正成功率,降低剖宫产率,并减少并发症的发生,安全性较高。     

臀先露、肩先露未足月胎膜早破对妊娠结局的影响

目的：探讨臀先露、肩先露未足月胎膜早破（PPROM）与妊娠结局间的关系,为临床处理PPROM提供参考。方法：收集单胎PPROM产妇235例,其中臀先露、肩先露并PPROM49例,头先露PPROM186例。观察两种类型PPROM的并发症及妊娠结局情况。结果：臀先露、肩先露组的潜伏期明显短于头先露组,其余一般情况与头先露组比较差异无统计学意义（P〉0．05）。臀先露、肩先露组AFI≤5cm、1minApgar评分≤7、脐带脱垂、死胎死产、新生儿死亡的比例明显高于头先露组（P〈0．05）。臀先露、肩先露是导致1minApgar评分降低的独立危险因素（P=0．021,OR=O．0821）。臀位、横位先露组与头先露组的剖宫产率、阴道分娩率比较差异有统计学意义（P=0．00）。臀先露、肩先露的产妇中行剖宫产者脐带脱垂、死胎死产发生率明显低于阴道分娩。结论：臀先露、肩先露PPROM更容易发生脐带脱垂、lminApgar评分≤7、AFI≤5cm、死胎死产,是1minApgar低评分的独立危险因素,因此一旦确诊为PPROM,且胎位为臀先露、肩先露,应给予及时处理。避免脐带受压,尽快行剖宫产,有利于改善围产儿结局。     

Do all hospitals need cesarean delivery capability? An outcomes study of maternity care in a rural hospital without on-site cesarean capability

OBJECTIVES: We analyzed perinatal outcomes at a rural hospital without cesarean delivery capability. STUDY DESIGN: This was a historical cohort outcomes study. POPULATION: The study population included all pregnant women at 20 weeks or greater of gestational age (n = 1132) over a 5-year period in a predominantly Native American region of northwestern New Mexico. OUTCOMES MEASURED: The outcomes studied included perinatal mortality, neonatal morbidity, obstetric emergencies, intrapartum and antepartum transfers, and cesarean delivery rate. We did a detailed case review of all obstetric emergencies and low-Apgar-score births at Zuni-Ramah Hospital and all cesarean deliveries for fetal distress at referral hospitals. RESULTS: Of the 1132 women in the study population, 64.7% (n = 735) were able to give birth at the hospital without operative facilities; 25.6% (n = 290) were transferred before labor; and 9.5% (n = 107) were transferred during labor. The perinatal mortality rate of 11.4 per 1000 (95% confidence interval, 5.1-17.8) was similar to the nationwide rate of 12.8 per 1000 even though Zuni-Ramah has a high-risk obstetric population. No instances of major neonatal or maternal morbidity caused by lack of surgical facilities occurred. The cesarean delivery rate of 7.3% was significantly lower than the nationwide rate of 20.7% (P <.001). The incidence of neonates with low Apgar scores (0.54%) was significantly lower than the nationwide rate (1.4%). The incidence of neonates requiring resuscitation (3.4%) was comparable to the nationwide rate (2.9%). CONCLUSIONS: The presence of a rural maternity care unit without surgical facilities can safely allow a high proportion of women to give birth closer to their communities. This study demonstrated a low level of perinatal risk. Most transfers were made for induction or augmentation of labor. Rural hospitals that do not have cesarean delivery capability but are part of an integrated perinatal system can safely offer obstetric services by using appropriate antepartum and intrapartum screening criteria for obstetric risk.     

Rates of cesarean delivery among Puerto Rican women--Puerto Rico and the U.S. mainland, 1992-2002

Cesarean delivery has been associated with greater risks for maternal morbidity, longer hospital stays, and rehospitalization after childbirth than vaginal delivery. On the U.S. mainland (i.e., 50 states and District of Columbia), rates of total cesarean delivery and primary cesarean delivery (i.e., for women without a previous cesarean) per 100 live births decreased from 1992 to 1996 before increasing from 1996 to 2002. During 2002, among all U.S. mainland births (approximately 4 million), 26% were by cesarean delivery; among all mainland births to women without a previous cesarean delivery, 18% were by primary cesarean. Cesarean delivery rates for Puerto Rican women who delivered on the U.S. mainland were similar to those for all women on the mainland. By contrast, among all 52,747 births in Puerto Rico in 2002, 45% were by cesarean delivery; among births in Puerto Rico to women without a previous cesarean delivery, 33% were primary cesarean deliveries. In addition, during 1996-2002, annual rates of vaginal births after cesarean delivery (VBAC) (i.e., per 100 live births to women who had a previous cesarean delivery) were lower in Puerto Rico than on the U.S. mainland. To compare trends in cesarean delivery during 1992-2002 among Puerto Rican women who delivered in Puerto Rico and on the U.S. mainland, CDC and the Puerto Rico Department of Health analyzed birth certificate data from the National Vital Statistics System (NVSS). This report summarizes the results of that analysis, which determined that, during 1992-2002, total and primary cesarean rates were consistently higher in Puerto Rico than among Puerto Rican women on the mainland. From 1996 to 2002, total and primary cesarean rates increased for Puerto Rican women in both places of delivery, but rates increased more sharply for women in Puerto Rico than on the mainland. The results suggest that measures to reduce the number of cesarean deliveries in Puerto Rico should focus on lowering the rate of primary cesarean deliveries, especially among women at low risk for a cesarean delivery.     

Maternal characteristics associated with place of delivery and neonatal mortality rates among very-low-birthweight infants,Georgia

To determine whether the Healthy People 2000 objective to deliver very-low-birthweight (VLBW) infants at subspecialty perinatal care centres was met, and if improvements in the regional perinatal care system could reduce neonatal mortality further for 2010, we examined place of delivery for VLBW infants, associated maternal characteristics and the potential impact on neonatal mortality. We used linked birth and death records for the 1994-96 Georgia VLBW (i.e. 500-1499 g) birth cohorts. Among 4770 VLBW infants, 77% were delivered at hospitals providing subspecialty perinatal care. The strongest predictor of birth hospital level was the mother's county of residence, defined using three levels: residence in a county with a subspecialty hospital, residence in a county adjacent to one with such a hospital or residence in a non-adjacent county. Eighty-nine per cent of infants born to women who resided in counties with subspecialty care hospitals delivered at such hospitals, compared with 53% of infants born to women who resided in a non-adjacent county. Women were also more likely to deliver outside subspecialty care if they had less than adequate prenatal care [adjusted odds ratio (AOR) 1.5, P-value = 0.0001]. The neonatal mortality rate varied by level of perinatal care at the birth hospital from 132.1/1000 to 283/1000 live births, with the highest death rate for infants born at hospitals offering the lowest level of care. Assuming that the differences in mortality were due to care level of the birth hospital, potentially 16-23% of neonatal deaths among VLBW infants could have been prevented if 90% of infants born outside subspecialty care were delivered at the recommended level. These findings suggest that a state's support of strong, collaborative, regional perinatal care networks is required to ensure that high-risk women and infants receive optimal health care. Improved access to recommended care levels should further reduce neonatal mortality until interventions are identified to prevent VLBW births.     

Changes in indications for cesarean delivery: United States, 1985 and 1994.

OBJECTIVES: The percentages of cesarean deliveries attributable to specific indications (breech, dystocia, fetal distress, and elective repeat cesarean) were computed for 1985 and 1994. METHODS: Data were derived from the 1985 and 1994 National Hospital Discharge Surveys. RESULTS: Dystocia was the leading indication for cesarean delivery in both years. In comparison with 1985, cesareans performed in 1994 that were attributable to dystocia and breech presentation increased, those attributable to fetal distress did not change significantly, and elective repeat cesareans declined. CONCLUSIONS: Studying indications for cesareans can be useful for hospitals, clinicians, and researchers in determining strategies to lower primary and repeat cesarean rates.