The Term Breech trial: Cesarean delivery improves perinatal outcome [Classics Series]

1. Among women with term fetuses in breech malpresentation, cesarean delivery was associated with reduction in perinatal and neonatal mortality and morbidity.

Original Date of Publication: October 2000

Study Rundown: While the majority of fetuses in breech malpresentation will spontaneously convert to cephalic presentation by term, 37 weeks gestation, a minority will remain in footling, complete or frank breech malpresentation. If these 3-4% of women fail or decline to undergo external cephalic version, they have historically been recommended to undergo planned cesarean section. This recommendation was based on findings of early studies that were potentially biased by lack of randomization, inexperienced delivery attendants and broad eligibility criteria that included poor candidates for vaginal breech delivery such as anomalous, compromised or footling breech-presenting fetuses. Accordingly, clinicians questioned whether vaginal delivery might be a similarly safe delivery mode compared to cesarean in the appropriate clinical setting. For example, in a multiparous patient in active labor with a healthy, uncompromised and appropriately sized fetus, vaginal delivery might confer an equally safe delivery for the fetus and is nearly a universally safer delivery mode for the mother compared to cesarean section. In the present work, authors performed a multicenter randomized trial to determine whether planned cesarean was superior to planned vaginal delivery.

This landmark study demonstrated that during delivery and through the first 6 weeks of life, planned cesarean section conferred a lower risk of neonatal morbidity and mortality compared to planned vaginal delivery. Strengths included randomized design, strict eligibility criteria and intention-to-treat analysis. Weaknesses included lack of randomization stratification by study site and dichotomization of parity (nulliparous or not), which introduced bias if clinician skill varied by center or if successful vaginal delivery varied between primiparous and multiparous women, respectively. Future investigations might restrict to parous women presenting in spontaneous labor to determine whether cesarean section confers significant fetal benefit among those women with the highest likelihood of successful vaginal breech delivery.

Click to read the study in the Lancet

Dr. Alan Peaceman, MD, talks to 2 Minute Medicine: Northwestern University School of Medicine; Chief, Division of Obstetrics and Gynecology-Maternal Fetal Medicine.

“The Term Breech Trial demonstrated that serious perinatal and neonatal complications are less common when women with fetuses in breech malpresentation are delivered by planned cesarean section. The absolute difference in neonatal complications was small but clinically significant such that nulliparous women with persistent breech malpresentation at term are typically counseled toward cesarean delivery.”

In-Depth [randomized trial]: Across more than 120 sites, a total of 2083 women with a term singleton pregnancy in frank or complete breech malpresentation were randomized to undergo planned cesarean delivery (n = 1041) or planned vaginal birth (n = 1042) in this multicenter randomized controlled trial. Primary outcome included perinatal and neonatal mortality or serious neonatal morbidity as well as maternal mortality or serious maternal morbidity through 6 weeks postpartum and were assessed via intention-to-treat analysis.

Perinatal and neonatal mortality and serious morbidity were less common among women randomized to cesarean compared to vaginal birth for delivery of term fetuses in breech malpresentation (1.6% vs. 5.0%, RR 0.33, 95% CI 0.19-0.56, p<0.0001). Among women randomized to planned cesarean delivery, 90.4% delivered by cesarean whereas 56.7% of those randomized to planned vaginal birth delivered vaginally. Maternal mortality and serious maternal morbidity did not differ between groups (p=0.35).

Image: PD

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