Relationship of cesarean delivery to lower birth weight-specific neonatal mortality in singleton breech infants in the United States

Term breech presentation-Intended cesarean section versus intended vaginal delivery-A systematic review and meta-analysis

INTRODUCTION

Three per cent of all infants are born in breech presentation, still the preferred way to deliver them remains controversial. The objective of this systematic review was to assess the safety for the mother and child depending on intended mode of delivery when the baby is in breech position at term.

MATERIAL AND METHODS

The population (P) was pregnant women with a child in breech presentation, from gestational week 34⁺⁰ . The intervention (I) was the intention to deliver by cesarean section, the comparison (C) was the intention to deliver vaginally. Outcomes (O) were perinatal mortality, perinatal morbidity, maternal mortality, maternal morbidity, conversion of delivery mode, and the mother's experience. Systematic literature searches were performed. We included randomized trials, cohort studies with more than 500 women/group and case series for more than 15 000 women published between 1990 and October 2021, written in English or the Nordic languages. The certainty of evidence was assessed using the GRADE approach and data were pooled in meta-analyses. PROSPERO registration number: CRD42020209546.

RESULTS

Thirty-two articles were included (with 530 604 women). The certainty of evidence was moderate or low because the study designs were mostly retrospective cohort studies. The only randomized trial showed reduced risk of perinatal mortality for planned cesarean section, risk ratio (RR) 0.27 (95% confidence interval [CI] 0.08-0.97, 2078 women, low certainty of evidence), stillbirths excluded. A meta-analysis of cohort studies resulted in a similar estimate, RR 0.36 (95% CI 0.25-0.51, 21 studies, 388 714 women, low certainty of evidence). We also found reduced risk for outcomes representing perinatal morbidity 0-28 days: 5-min Apgar score less than 7 in one randomized controlled trial: RR 0.27 (95% CI 0.12-0.58, 2033 women, moderate certainty of evidence), and in a meta-analysis: RR 0.1 (95% CI 0.14-0.26, 18 studies, 217 024 women, moderate certainty of evidence); APGAR score less than 4 at 5 min: RR 0.39 (95% CI 0.19-0.81, five studies, 44 498 women, low certainty of evidence); and pH less than 7.0: RR 0.23 (95% CI 0.12-0.43, four studies, 13 440 women, low certainty of evidence). Outcomes for the mother were similar in the groups except for reduced risk for experience of urinary incontinence in the group of planned cesarean section: RR 0.62 (95% CI 0.41-0.93, one study, 1940 women, low certainty of evidence). The conversion rate from planned vaginal delivery to emergency cesarean section ranged from 16% to 51% (median 41.8%, 10 studies, 50 763 women, moderate certainty of evidence).

CONCLUSIONS

Intended cesarean section may reduce the risk of perinatal mortality and perinatal as well as some maternal morbidity compared with intended vaginal delivery. It is uncertain whether there is any difference in maternal mortality. The conversion rate from intended vaginal delivery to emergency cesarean section is high.

Neonatal mortality by attempted route of delivery in early preterm birth

OBJECTIVE

We sought to study neonatal outcomes in early preterm births by delivery route.

STUDY DESIGN

Delivery precursors were analyzed in 4352 singleton deliveries, 24 0/7 to 31 6/7 weeks' gestation. In a subset (n = 2906) eligible for a trial of labor, neonatal mortality in attempted vaginal delivery (VD) was compared to planned cesarean delivery stratified by presentation.

RESULTS

Delivery precursors were classified as maternal or fetal conditions (45.7%), preterm premature rupture of membranes (37.7%), and preterm labor (16.6%). For vertex presentation, 79% attempted VD and 84% were successful. There was no difference in neonatal mortality. For breech presentation, at 24 0/7 to 27 6/7 weeks' gestation, 31.7% attempted VD and 27.6% were successful; neonatal mortality was increased (25.2% vs 13.2%, P = .003). At 28 0/7 to 31 6/7 weeks' gestation, 30.5% attempted VD and 17.2% were successful; neonatal mortality was increased (6.0% vs 1.5%, P = .016).

CONCLUSION

Attempted VD for vertex presentation has a high success rate with no difference in neonatal mortality unlike breech presentation.

Vaginal breech delivery in very low birth weight (VLBW) neonates: experience of a single center

AIMS

To compare the short-term maternal and neonatal outcomes of very low birth weight (VLBW) breech singletons by mode of delivery.

METHODS

All breech fetuses born from 24-0/7 to 26-6/7 weeks' gestation at our institution between 2000 and 2008 were eligible for the study. Abstracted medical record data included maternal demographics, delivery data, and neonatal outcomes.

RESULTS

There were 26 vaginal and 39 cesarean deliveries. Maternal age did not differ between groups; gestational age was greater in the cesarean group by five days. Short-term neonatal outcomes did not differ between groups. Of the 39 cesarean deliveries, 27 involved classical uterine incisions. Estimated blood loss (732 mL vs. 362 mL) and postpartum infection rate (26% vs. 4%) were greater with cesarean delivery.

CONCLUSION

Neonatal outcome is not improved in VLBW infants born by cesarean section. Given the morbidity of classical cesarean sections, vaginal delivery of the breech VLBW infant may be safely considered.

Cesarean or vaginal delivery for the breech fetus at the threshold of viability: results from a maternal-fetal medicine specialists survey

OBJECTIVE

To determine how United States Maternal-Fetal medicine specialists recommend delivery of a breech fetus at the threshold of viability.

METHODS

U.S. Society for Maternal-Fetal Medicine (SMFM) members were surveyed about; geographic location, practice type, whether they performed deliveries, definition of threshold for viability, recommendations for delivery of a breech fetus at the threshold of viability, and if the current medical-legal climate had any bearing on their decisions. Chi-Square and Fisher's Exact tests were used for analysis.

RESULTS

510 SMFM members responded to the questionnaire. The highest percentage of respondents stated '23 weeks' (31%) as the cutoff for viability, followed by '24 weeks' (21%) and '23 weeks or 500 g' (10%). Seventy percent recommended cesarean delivery for a breech fetus at the threshold of viability. The majority of respondents based their decision on 'published data' or 'expert opinion', however, 58.6% reported they felt current medical evidence was inadequate to support a recommendation. Fifty-three percent stated their recommendations are affected by medical-legal concerns.

CONCLUSION

The majority of U.S. maternal fetal-medicine specialists who responded would recommend cesarean delivery for a breech fetus at the threshold of viability, despite the belief that there is inadequate evidence in the literature to support this recommendation.

Population trends in cesarean delivery for breech presentation in the United States, 1997-2003

OBJECTIVE

The objective of the study was to determine whether cesarean delivery for breech has increased in the United States.

STUDY DESIGN

We calculated cesarean rates for term singletons in breech/malpresentation from 1997 to 2003 using National Center for Health Statistics data. We compared rates by sociodemographic groups and state. Multivariable logistic regression models were constructed to see whether factors associated with cesarean delivery differed over time.

RESULTS

Breech cesarean rates increased overall from 83.8% to 85.1%. There was a significant increase in rates for most sociodemographic groups. There was little to no increase for mothers younger than 30 years old. There was wide variability in rates by state, 61.6-94.2% in 1997. Higher breech incidence correlated with lower cesarean rates, suggesting potential state bias in reporting breech.

CONCLUSION

In the United States, breech infants are predominantly born by cesarean. There was a small increase in this trend from 1998 to 2002. There is wide variability by state, which is not explained by sociodemographic patterns and may be due to reporting differences.

Early preterm breech delivery: is a policy of planned vaginal delivery associated with increased risk of neonatal death?

OBJECTIVE

The purpose of this study was to compare neonatal death rates in preterm singleton breech deliveries from 26 weeks to 29 weeks 6 days of gestation in centers with either a policy of planned vaginal delivery (PVD) or planned cesarean delivery (PCD).

STUDY DESIGN

Women with preterm singleton breech deliveries were identified from the databases of 3 perinatal centers and classified as PVD or PCD according to the center's management policy.

RESULTS

The study included 84 women in the PVD group and 85 women in the PCD group. Incidence of neonatal death was similar in both (10.7% vs 7.1%; P = .40). Head entrapment (adjusted odds ratio, 7.2; 95% CI, 1.7-29.8), preterm premature rupture of membranes at <24 weeks of gestation (adjusted odds ratio, 13.3; 95% CI, 2.8-63.0), and gestational age between 26 weeks and 27 weeks 6 days of gestation (adjusted odds ratio, 4.7; 95% CI, 1.2-18.5) were associated independently with neonatal death.

CONCLUSION

Risk of neonatal death was not associated with any particular policy of mode of delivery.

Influence of mode of delivery on neonatal mortality and morbidity in spontaneous preterm breech delivery

OBJECTIVE

To study the association between mode of delivery and neonatal outcome in singleton pregnancy with breech presentation and preterm birth, due to premature labour (PTL) and/or preterm premature rupture of the membranes (pPROM).

DESIGN AND METHODS

Information on preterm (gestational week 25-36) singleton births in breech presentation in Sweden during 1990-2002 was obtained from the Swedish Medical Birth Registry and the Swedish Hospital Discharge Registry. The study groups included 1975 caesarean and 699 vaginal deliveries with a diagnosis of PTL or pPROM, without pregnancy complications implying a high risk of fetal compromise. The rates of infant respiratory distress syndrome (IRDS), intraventricular haemorrhage (IVH), low Apgar scores, and neonatal deaths were compared between infants delivered vaginally and by caesarean section. Odds ratios were calculated with adjustment for gestational age, year of birth, maternal age and parity.

RESULTS

The risk of neonatal death and the risk of an Apgar score below 5 min postnatally were both lower after caesarean delivery (OR 0.4; 95% CI 0.2-0.7, and OR 0.4; 95% CI 0.3-0.7, respectively), whereas the risk of IRDS was increased (OR 2.1; 95% CI 1.4-3.2). A diagnosis of IRDS was not associated with mortality (OR 0.8; 95% CI 0.5-1.5). IVH was not associated with mode of delivery (OR 1.2; 95% CI 0.5-2.8).

CONCLUSION

The lower neonatal mortality after CS supports a policy of caesarean delivery of the preterm breech.

Cesarean section in term breech presentations: do rates of adverse neonatal outcomes differ by hospital birth volume?

AIM

To determine if risk of adverse neonatal outcomes among term breech infants delivered by cesarean section differs by volume of such births at the delivering hospital.

METHODS

We conducted a population-based cohort study using Missouri linked birth and death certificate files. The study population included 10,106 singleton, term, normal birth weight infants in breech presentation delivered by cesarean section. Infants were linked to hospitals where delivered. These hospitals were divided into terciles (low, medium, and high volume) based on the median number of annual deliveries during 1993-1999. The primary outcome was presentation of at least one adverse neonatal outcome. Adjusted odds ratios and 95% confidence intervals (CI) were calculated using logistic regression analysis.

RESULTS

The rate of any adverse outcome was 17.8, 15.0, and 5.9 cases per 1,000 deliveries at low-, medium-, and high-volume hospitals, respectively. All component adverse outcomes occurred more frequently in low- or medium-volume hospitals than in high-volume hospitals. Compared to breech infants delivered at high-volume hospitals, those delivered at low-volume and medium-volume hospitals were 2.7 (CI 1.6, 4.5) and 2.4 (CI 1.4, 4.1) times, respectively, more likely to experience an adverse outcome after adjusting for significant confounders.

CONCLUSIONS

Prospective studies should explore the source of these risk differences.

Survival advantage associated with cesarean delivery in very low birth weight vertex neonates

OBJECTIVE

To identify the indications for and any survival advantage associated with very low birth weight (VLBW) neonates delivered by cesarean.

METHODS

Maternal and infant data from the National Center for Health Statistics linked birth/death data set for 1999 to 2000 were analyzed. Maternal conditions associated with cesarean delivery were compared among birth weight groups for vertex neonates. Birth weight-specific 28-day mortality rates and relative risks were calculated with 95% confidence intervals. Multivariate logistic regression was performed to adjust for other factors that may be associated with survival.

RESULTS

Cesarean delivery occurred frequently, more than 40% in most VLBW birth weight groups. Conditions associated with cesarean delivery in VLBW vertex neonates differed from those seen in non-VLBW vertex neonates. A survival advantage was associated with cesarean delivery in the birth weight analysis up to 1,300 g (P < .05). This decreased mortality for VLBW neonates delivered by cesarean persisted after adjusting for other factors associated with mortality.

CONCLUSION

Very low birth weight vertex neonates are often born by cesarean delivery and have different maternal risk profiles from non-VLBW vertex neonates born by this route. Neonatal mortality was decreased in VLBW neonates delivered by cesarean. Further study is warranted to determine whether this may be a causal relationship or a marker of quality of care.

LEVEL OF EVIDENCE

II-2.

Risk factors for neonatal mortality among extremely-low-birth-weight infants

OBJECTIVE

The purpose of this study was to examine characteristics associated with neonatal mortality among extremely low-birth-weight infants (< or = 1000 g).

STUDY DESIGN

A population-based, case-control study using linked Missouri birth and death certificates from 1989 to 1997 was conducted. Cases (n = 835) were defined as extremely low-birth-weight infants that died within 28 days of birth. Controls (n = 907) were randomly selected from extremely low-birth-weight infants that were alive at 1 year and were frequency matched to subjects by birth year and birth weight.

RESULTS

Infants born with severe congenital anomalies and at the youngest gestational ages were at greatest risk for neonatal mortality. Other significant risk factors included maternal age (< 18 and > 34 years), vaginal delivery, nontertiary hospital care, malpresentation, male gender, and small for gestational age. Black race and preeclampsia were protective against early death.

CONCLUSIONS

The risk of neonatal mortality among extremely low-birth-weight infants was associated with several maternal, infant, and obstetric factors, some of which may be preventable.

Inappropriate use of randomised trials to evaluate complex phenomena: case study of vaginal breech delivery

As randomised trials continue to ascend in the evolution of evidence based medicine, we must recognise and respect their limitations when examining complex phenomena in heterogeneous populations

Labor and delivery factors in brain damage, disabling cerebral palsy, and neonatal death in low-birth-weight infants

OBJECTIVE

We assessed the relationships between active labor and neonatal death, neonatal brain damage, and disabling cerebral palsy in low-birth-weight infants.

STUDY DESIGN

A population-based cohort of 961 infants with birth weights of 580 to 2000 g and gestational ages >or=26 completed weeks. Neonatal brain damage was assessed by ultrasound scanning in the first weeks of life; disabling cerebral palsy was assessed at 2 years of age (corrected for gestational age).

RESULTS

After being controlled for possible confounders, active labor was associated significantly with an increased risk of parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 2.3; 95% CI, 1.2-4.5) but not with germinal matrix/intraventricular hemorrhage (odds ratio, 1.3; 95% CI, 0.8-2.1), neonatal death (odds ratio, 1.8; 95% CI, 0.8-4.0), or disabling cerebral palsy (odds ratio, 1.6; 95% CI, 0.7-3.7). In vertex presentations only, active labor was associated with a nearly 4-fold increase in risk of neonatal death (odds ratio, 3.8; 95% CI, 1.3-10.9). In nonvertex presentations only, active labor was associated strongly with parenchymal echodensities/lucencies and/or ventricular enlargement (odds ratio, 4.3; 95% CI, 1.2-15.6) and disabling cerebral palsy (odds ratio, 8.2; 95% CI, 1.4-49.9).

CONCLUSION

The only adverse outcome that was associated consistently with active labor was parenchymal echodensities/lucencies and/or ventricular enlargement. Fetal presentation modified the relationships between active labor and adverse outcomes. Delivery mode (whether vaginal or cesarean delivery) was not associated with any of the outcomes that were evaluated.

Breech vaginal delivery at or near term

Three percent to 4% of term fetuses will be breech at delivery. Evidence from randomized controlled trials has found a policy of planned cesarean section to be significantly better for the singleton fetus in breech presentation at term compared to a policy of planned vaginal birth. However, some women may wish to avoid cesarean section and for others, cesarean section may not be possible. We undertook this review to identify factors associated with higher and lower risk of adverse fetal or neonatal outcome at term during vaginal breech delivery. We searched MEDLINE from 1966 to 2002 using the search terms vaginal breech delivery and breech presentation and retrieved all relevant articles. We also reviewed personal references and reference lists of articles retrieved. Women who are older or who have a fetus that is either in footling presentation, has a hyperextended head or is estimated to weigh <2500 g or >4000 g may be at higher risk of adverse fetal outcome. Prolonged labor or not having an experienced clinician at vaginal breech birth may also increase the risk. Women with a fetus in breech presentation at term should be offered the option of delivery by planned cesarean section and should be informed that this will reduce their risk of adverse fetal or neonatal outcome. Practitioners should develop and maintain skills at vaginal breech delivery for those women not wishing or not able to be delivered by cesarean section.

Breech presentation at term: morbidity and mortality according to the type of delivery at Port Royal Maternity hospital from 1993 through 1999

OBJECTIVE

To compare neonatal morbidity and mortality at Port Royal Maternity between 1993 and 1999 for infants with a singleton breech presentation born after 37 weeks, according to planned mode of delivery.

STUDY DESIGN

Retrospective study of 501 patients of whom vaginal delivery was planned in 322 (64%) or/and cesarean in 179 (36%).

RESULTS

Severe neonatal morbidity was similar in the two groups (13/322, 4.0% versus 8/179, 4.5%; P=0.82); severe trauma morbidity was not significantly higher in the "planned vaginal delivery" group (3/322, 0.9% versus 1/179, 0.06%; P=0.16); there were no long-term sequelae. Mortality was not higher when vaginal delivery was planned.

CONCLUSION

We have not found in this series any excess of morbidity or mortality attributable to vaginal delivery of breech presentations. This work does not indicate that we should change our obstetrical practice in the light of other recently-published studies.

Variations in intraventricular hemorrhage incidence rates among Canadian neonatal intensive care units

OBJECTIVES

To examine the variation in intraventricular hemorrhage (IVH) incidence among neonatal intensive care units and identify potentially modifiable risk factors.

STUDY DESIGN

Multiple logistic regression analysis was used to examine variations in > or =grade 3 IVH, adjusting for baseline population risk factors, admission illness severity, and therapeutic risk factors. Subjects were born at <33 weeks' gestational age, admitted within 4 days of life to 1 of 17 participating Canadian NICU network sites in 1996-97, and had neuroimaging in the first 2 weeks of life.

RESULTS

Of 5126 subjects <33 weeks' gestational age, 3806 had neuroimaging reports. Five of 17 sites had significantly (P <.05) different crude incidence rates of grade 3-4 IVH (odds ratios [OR] 0.2, 3.2, 2.6, 2.1, 1.9) than the hospital with median incidence. With adjustment for baseline population risk factors, perinatal risks, and admission illness severity, IVH incidence rates remained significantly (P <.05) higher at 3 sites (OR 2.9, 2.3 and 2.1). Inclusion of therapy-related variables (treatment of acidosis and vasopressor use on the day of admission) in the model eliminated all site differences.

CONCLUSIONS

IVH incidence rates vary significantly. Patient characteristics explain some of the variance. Early treatment of hypotension and acidosis and mode of delivery are potentially modifiable factors and warrant further study in IVH prevention.

External cephalic version with epidural anaesthesia after failure of a first trial with beta-mimetics

OBJECTIVE

To assess the efficacy, tolerance, and cost of external version under epidural anaesthesia and beta-mimetic tocolysis after the failure of an initial attempt with tocolysis alone.

DESIGN

Prospective open study.

PARTICIPANTS

Sixty-eight women with breech presentation at around 36 weeks of gestation and an attempted external cephalic version under salbutamol that failed, who consented to try a second attempt under epidural anaesthesia.

RESULTS

The overall success rate under epidural anaesthesia was 39.7% (27/68), and complications occurred in two cases. The total cost of attempting external version was higher than the cost of expectant management.

CONCLUSIONS

The efficacy of external cephalic version under epidural reduces the rate of caesarean sections associated with breech presentation, but its relative safety remains in question. Moreover, our economic analysis discourages the hope of lowered costs suggested by earlier reports that this technique is more expensive than expectant management, except in institutions with a policy of systematic caesarean sections when version fails.

Comparison of vaginal and cesarean section delivery for fetuses in breech presentation

OBJECTIVES

Our purpose was to evaluate the perinatal mortality and morbidity of deliveries with fetuses presenting by the breech comparing outcomes of two groups according to mode of delivery: vaginal and cesarean section.

RESULTS

Of 756 fetuses studied, 271 were delivered vaginally and 485 by cesarean section. In infants weighing > or = 1500 grams, "further corrected" mortality and morbidity rates were low and similar for both delivery routes: one neonatal death (NNM) in each. Among very low birth weight (VLBW) infants (< 1500 grams) the "further corrected" mortality rate was higher in the vaginal group: 57.4%, and 18.0% in abdominal deliveries (odds ratio [OR] = 6.1, 95% CI: 3.1 to 12.1). Likewise, rate of depression at five minutes were higher in the vaginal group (p < 0.001). However, the average fetal weight among the vaginal deliveries VLBW (787 grams) was 250 grams less than in the cesarean section group (1040 grams). After adjustment for fetal weight, gestational age, and other prognostic variables the odds ratio for neonatal death was no longer statistically significant (adjusted OR = 2.1, 95% CI: 0.9 to 5.2, p = 0.105). Comparison of planned vaginal delivery with elective cesarean section yielded smaller differences (adjusted OR for neonatal death = 1.3, 95% CI: 0.6 to 2.9, p = 0.525).

CONCLUSION

The poor perinatal outcomes of breech delivered infants are due primarily to VLBW, congenital malformations, and premature labor. Although abdominal delivery had a lower NNM rate than vaginal delivery, the difference was not significant after adjustment for confounding factors. The results confirm the findings of a previously analyzed similar series delivered at our institution between 1980 and 1987. They suggest that, with appropriate technique, abdominal delivery is not mandatory in breech presentation.