The Lancet OCTOBER 21, 2000

Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial

Mary E. Hannah, Walter J. Hannah, Sheila A. Hewson, Ellen D. Hodnett, Saroj Saigal, Andrew R. Willan, for the Term Breech Trial Collaborative Group

Bottom Line

This landmark international multicenter randomized trial demonstrated that a policy of planned cesarean section, compared to a policy of planned vaginal birth, significantly reduces perinatal and neonatal mortality and serious neonatal morbidity in singleton term breech pregnancies.

Key Findings

1. The primary outcome of perinatal mortality, neonatal mortality, or serious neonatal morbidity was significantly lower in the planned cesarean section group (17 of 1,039; 1.6%) compared to the planned vaginal birth group (52 of 1,039; 5.0%) (relative risk 0.33; 95% CI 0.19-0.56; p<0.0001).
2. There was no statistically significant difference between the planned cesarean section group (41 of 1,041; 3.9%) and the planned vaginal birth group (33 of 1,042; 3.2%) regarding maternal mortality or serious maternal morbidity (relative risk 1.24; 95% CI 0.79-1.95; p=0.35).
3. Among the planned cesarean group, 90.4% underwent cesarean delivery, while 56.7% of those in the planned vaginal birth group achieved a vaginal delivery.

Study Design

Design
RCT
Open-Label
Sample
2,083
Patients
Duration
6 wk
Median
Setting
Multicenter, International
Population Women with a singleton fetus in a frank or complete breech presentation at term (≥37 weeks gestation).
Intervention Planned cesarean section
Comparator Planned vaginal birth
Outcome Composite of perinatal mortality, neonatal mortality, or serious neonatal morbidity; OR composite of maternal mortality or serious maternal morbidity.

Study Limitations

The study has been criticized for the inclusion of women recruited during active labor, which complicates standardized management and outcome assessment.
Concerns exist regarding the lack of consistent expertise in vaginal breech delivery among participating clinicians at all study sites.
The trial's findings regarding short-term neonatal benefits were not replicated in subsequent long-term follow-up assessments at two years of age, which showed no significant difference in death or neurodevelopmental delay between the groups.
Critics argue that the results are not generalizable to settings with specialized, experienced breech delivery services.

Clinical Significance

The publication of this trial led to a paradigm shift in obstetric practice globally, resulting in a dramatic increase in planned cesarean delivery rates for term breech presentations and a significant decline in the practice of vaginal breech birth in many developed nations.

Historical Context

Prior to this trial, management of term breech presentation was controversial and varied widely, with observational data suggesting potential risks to vaginal breech delivery but lacking high-level evidence from randomized controlled trials.

Guided Discussion

High-yield insights from every perspective

Med Student
Medical Student

In the context of term breech presentation, why is the 'after-coming head' considered a primary mechanical risk during a vaginal delivery compared to a cephalic presentation?

Key Response

In a cephalic birth, the largest part of the fetus (the head) dilates the cervix first. In a breech birth, the smaller buttocks or feet may pass through a partially dilated cervix, but the larger, non-malleable head can become trapped (head entrapment) or lead to umbilical cord compression between the head and the pelvic rim, causing acute fetal hypoxia.

Resident
Resident

Following the publication of the Term Breech Trial, many departments moved toward universal elective cesarean for breech. However, if a patient insists on a trial of labor, what specific fetal and maternal criteria must be met to minimize morbidity according to modern obstetric standards?

Key Response

Modern criteria for a safe trial of breech labor include: frank or complete breech (not footling), fetal weight between 2500g and 4000g, absence of fetal head hyperextension on ultrasound, a 'favorable' maternal pelvis, and the presence of a clinician experienced in breech maneuvers.

Fellow
Fellow

How does the 2-year follow-up data from the Term Breech Trial participants complicate the initial recommendation for universal cesarean section, and how should this be integrated into patient counseling?

Key Response

While the initial 2000 study showed a significant reduction in short-term neonatal morbidity, the 2-year follow-up (Whyte et al., 2004) found no significant difference in the risk of death or neurodevelopmental delay between the two groups. This suggests that many of the acute morbidities captured in the initial study did not result in long-term permanent disability, which is a critical distinction when counseling patients on risk.

Attending
Attending

Considering the 'skill-rot' phenomenon that followed the Term Breech Trial, what strategies should academic departments implement to ensure that the next generation of providers can safely manage an unavoidable or precipitous breech delivery?

Key Response

Since elective cesarean has become the norm, residents have fewer opportunities for hands-on experience. This necessitates high-fidelity simulation training, the use of pelvic models for maneuvers like Bracht or Mauriceau-Smellie-Veit, and potentially identifying 'breech teams' or centers of excellence where low-risk vaginal breech births are still performed and taught.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD
PhD

The Term Breech Trial was criticized for its use of a composite primary outcome. What are the methodological implications of combining rare events like perinatal mortality with more common events like transient brachial plexus injury or bone fractures in a single effect estimate?

Key Response

Composite outcomes can be dominated by the most frequent, least severe components, potentially masking the true effect on the most critical endpoints (mortality). If the treatment effect is inconsistent across the components of the composite, the resulting 'relative risk reduction' can be misleadingly high or fail to reflect the clinical utility of the intervention for life-threatening events.

Journal Editor
Journal Editor

As a reviewer, how would you evaluate the external validity of the Term Breech Trial given that nearly 33% of the participating centers were in developing countries with different standards of intrapartum monitoring and neonatal intensive care access?

Key Response

The benefit of planned cesarean was much more pronounced in 'high national perinatal mortality rate' countries than in 'low' rate countries. A critical reviewer would flag that applying these results universally to high-resource settings—where monitoring and rescue are more robust—might overestimate the safety benefit of cesarean sections in those specific environments, as seen later in the PREMODA study.

Guideline Committee
Guideline Committee

How do current ACOG and RCOG guidelines balance the findings of the Term Breech Trial with the subsequent PREMODA study when determining the Level of Evidence for planned vaginal breech delivery?

Key Response

ACOG Committee Opinion 745 and RCOG Green-top Guideline 20b acknowledge the Term Breech Trial but allow for planned vaginal delivery in selected cases. RCOG specifically notes that with strict selection criteria and experienced staff (as demonstrated in the PREMODA study), the perinatal mortality rate of vaginal breech delivery may approach that of cephalic presentation, moving the recommendation from a strict 'C-section only' to a 'shared decision-making' model (Level B/C evidence).

Clinical Landscape

Noteworthy Related Trials

2006

PREMODA Study

n = 8,107 · Am J Obstet Gynecol

Tested

Planned vaginal delivery for breech presentation

Population

Women with singleton breech presentation at term

Comparator

Planned cesarean section

Endpoint

Perinatal mortality and serious neonatal morbidity

Key result: There were no significant differences in neonatal outcomes between planned vaginal delivery and cesarean section in strictly selected patients.
2013

Twin Birth Study

n = 2,804 · NEJM

Tested

Planned cesarean section for twin delivery

Population

Women with twins at 32-38 weeks gestation

Comparator

Planned vaginal delivery

Endpoint

Composite of fetal or neonatal death or serious neonatal morbidity

Key result: Planned cesarean section did not significantly decrease the risk of fetal or neonatal death or serious neonatal morbidity compared with planned vaginal delivery.
2015

PROBSTAT Study

n = 580 · BJOG

Tested

Planned vaginal delivery with strict criteria

Population

Women with breech presentation at term

Comparator

Planned cesarean section

Endpoint

Composite of perinatal mortality and serious neonatal morbidity

Key result: No significant difference in adverse neonatal outcomes was observed between groups, supporting the safety of vaginal breech birth in highly selected cases.

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