The Lancet October 21, 2000

Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial (Term Breech Trial)

Mary E Hannah, Walter J Hannah, Sheila A Hewson, Ellen D Hodnett, Saroj Saigal, Andrew R Willan

Bottom Line

A landmark international randomized controlled trial demonstrating that planned cesarean section significantly reduces perinatal mortality and serious neonatal morbidity for term breech presentations compared to planned vaginal birth, without significantly increasing severe maternal complications.

Key Findings

1. Perinatal mortality, neonatal mortality, or serious neonatal morbidity was significantly lower in the planned cesarean section group compared to the planned vaginal birth group (1.6% [17 of 1039] vs. 5.0% [52 of 1039]; RR 0.33, 95% CI 0.19-0.56, p<0.0001).

2. There were no significant differences in maternal mortality or serious maternal morbidity between the planned cesarean and planned vaginal delivery groups (3.9% [41 of 1041] vs. 3.2% [33 of 1042]; RR 1.24, 95% CI 0.79-1.95, p=0.35).

3. Of the 1,041 women assigned to planned cesarean section, 90.4% were delivered by cesarean section.

4. Of the 1,042 women assigned to planned vaginal birth, 56.7% delivered vaginally.

Study Design

Design

Randomized Controlled Trial

Open-Label

Sample

2,088

Patients

Duration

6 weeks

Median

Setting

26 countries

Population Women with a singleton fetus in a frank or complete breech presentation at term (at least 37 weeks gestation).

Intervention Planned cesarean section.

Comparator Planned vaginal birth.

Outcome Composite of perinatal or neonatal mortality or serious neonatal morbidity; and maternal mortality or serious maternal morbidity.

Study Limitations

• The trial allowed a wide variation in the criteria and required skill levels for accoucheurs managing vaginal breech deliveries, drawing criticism that practitioners with suboptimal breech experience were included.

• The trial was halted early (after 2,088 of the planned 2,800 enrollments) due to clear neonatal benefit, which can sometimes overestimate effect sizes.

• Intrapartum management protocols in the vaginal group were criticized for not strictly reflecting idealized criteria for safe vaginal breech birth (e.g., continuous fetal monitoring parameters).

• While short-term neonatal benefits were profound, subsequent 2-year follow-up showed no significant differences in neurodevelopmental outcomes or death, complicating the long-term clinical narrative.

Clinical Significance

The Term Breech Trial catalyzed a dramatic, worldwide paradigm shift in obstetric practice. Following its publication, major obstetric societies (including ACOG) recommended planned cesarean section for term singleton breech presentations. Consequently, the incidence of vaginal breech deliveries plummeted, leading to a secondary challenge: the rapid loss of clinical expertise in safely performing vaginal breech births for women who present in advanced labor or decline surgery.

Historical Context

Prior to 2000, the safest delivery method for term breech presentation was heavily debated. Many experienced clinicians safely performed vaginal breech deliveries for strictly selected candidates, while others increasingly favored cesarean sections due to fears of birth trauma or asphyxia. The Term Breech Trial was designed to provide definitive Level I evidence. Its immediate effect was profound, nearly eliminating routine vaginal breech birth in many Western nations, though later observational studies (like the French PREMODA study) suggested that with strict criteria and expert operators, vaginal breech delivery might still be reasonably safe.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

What anatomical and physiological factors explain the higher perinatal mortality and neonatal morbidity associated with vaginal breech delivery compared to cephalic presentation as observed in the Term Breech Trial?

Key Response

Foundational knowledge involves understanding that in a breech presentation, the fetal head (the largest and least compressible part) delivers last. This introduces severe risks such as head entrapment in an incompletely dilated cervix and umbilical cord prolapse, leading to acute asphyxia, hypoxic-ischemic encephalopathy, or mechanical birth trauma.

Resident

A patient at 38 weeks with a frank breech presentation declines external cephalic version and strongly desires a vaginal birth. Based on the Term Breech Trial and current ACOG guidelines, how do you counsel her on the risks, and what strict clinical criteria must be met to even consider this request?

Key Response

Residents must apply the TBT data demonstrating significantly higher neonatal morbidity and mortality with planned vaginal birth, while also knowing the strict criteria for exceptions: frank or complete breech, flexed fetal head, normal amniotic fluid volume, estimated fetal weight 2500-4000g, and the immediate availability of a highly experienced provider and operating room for emergent cesarean.

Fellow

How do the 2-year pediatric follow-up data of the Term Breech Trial, which showed no significant difference in death or neurodevelopmental delay between the two groups, complicate the interpretation of the original short-term neonatal outcomes, and how should this nuance influence maternal-fetal counseling?

Key Response

Fellows must critically evaluate long-term outcomes. The 2-year data revealed that the initial severe short-term neonatal morbidity did not necessarily translate to long-term neurodevelopmental deficits. This suggests the absolute risk of long-term harm from vaginal breech delivery may be lower than the initial short-term data implied, requiring more nuanced, evidence-based shared decision-making.

Attending

Given the widespread global adoption of the Term Breech Trial's findings, how does a modern attending obstetrician manage the systemic consequence of skill decay in vaginal breech extraction when faced with an inevitable, unexpected vaginal breech delivery on the labor ward?

Key Response

Attendings face the practical, practice-changing reality that the TBT essentially eliminated routine vaginal breech training. Maintaining competence via high-fidelity simulation, establishing clear rapid-response protocols, and mentoring junior staff are major contemporary challenges derived directly from the epidemiological shift caused by this trial.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

How did the inclusion of 121 diverse international centers with varying levels of intrapartum electronic fetal monitoring and neonatal resuscitation capabilities in the Term Breech Trial introduce potential confounding, and how does this affect the generalizability of the findings to high-resource tertiary care centers?

Key Response

Methodological critique reveals that poor outcomes in the vaginal group may have been disproportionately driven by inadequate monitoring or lacking resuscitation resources in lower-resource settings, rather than the intrinsic mode of delivery itself. This raises significant questions about the generalizability (external validity) of the effect size to modern, well-equipped hospitals.

Journal Editor

If critically appraising the Term Breech Trial today, what major threats to internal validity would you flag regarding the protocol's subjective definition and standardization of what constitutes an 'experienced clinician' across the participating global sites?

Key Response

A seasoned reviewer would flag that defining clinical expertise in a surgical/procedural trial is notoriously difficult. Because practitioner skill is the primary driver of safety in the vaginal birth arm, the lack of objective, standardized credentialing for an 'experienced clinician' introduces significant operator bias and threatens the reliability of the control arm's safety profile.

Guideline Committee

Following the Term Breech Trial, guidelines rapidly shifted to universally recommend planned cesarean delivery. Integrating subsequent evidence and evaluating ACOG Committee Opinion 745, should modern guidelines maintain an absolute recommendation for cesarean, or provide a graded framework for carefully selected vaginal breech deliveries?

Key Response

Guideline committees must balance the TBT's initial strong Grade A evidence against long-term follow-up data, registry studies, and patient autonomy. Current guidelines acknowledge that while planned cesarean is preferred, planned vaginal breech delivery may be reasonable under strict, specific, and hospital-approved protocols with robust informed consent, reflecting a move away from absolute prohibition toward conditional risk-stratification.

Clinical Landscape

Noteworthy Related Trials

2006

PREMODA Study

n = 8,105 · Am J Obstet Gynecol

Tested

Planned vaginal delivery with strict selection criteria

Population

Women with a singleton breech fetus at term

Comparator

Planned cesarean delivery

Endpoint

Composite of fetal/neonatal mortality or severe neonatal morbidity

Key result: There was no significant difference in severe neonatal morbidity or perinatal mortality between planned vaginal delivery and planned cesarean delivery when strict management protocols were followed.

2011

Early External Cephalic Version 2 Trial

n = 1,543 · Lancet

Tested

Early external cephalic version (ECV) at 34 to 35 weeks gestation

Population

Women with a singleton breech fetus

Comparator

Standard ECV at 37 or more weeks gestation

Endpoint

Rate of cesarean delivery

Key result: Early ECV increased the likelihood of having a cephalic presentation at birth but did not significantly decrease the overall rate of cesarean delivery compared to standard ECV.

2013

Twin Birth Study

n = 2,804 · NEJM

Tested

Planned vaginal delivery

Population

Women with twin pregnancies at 32 to 38 weeks gestation with the first twin in cephalic presentation

Comparator

Planned cesarean delivery

Endpoint

Composite of fetal or neonatal death or serious neonatal morbidity

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

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