Risk factors for adverse outcomes in vaginal preterm breech labor

Georg Macharey,Anna Toijonen,Seppo Heinonen,Mika Gissler

doi:10.1007/s00404-020-05731-y

Abstract

PurposeTo assess the risk factors for adverse outcomes in attempted vaginal preterm breech deliveries.MethodsA retrospective case–control study, including 2312 preterm breech deliveries (24 + 0 to 36 + 6 gestational weeks) from 2004 to 2018 in Finland. The preterm breech fetuses with adverse outcomes born vaginally or by emergency cesarean section were compared with the fetuses without adverse outcomes with the same gestational age. A multivariable logistic regression analysis was used to calculate the risk factors for adverse outcomes (umbilical arterial pH below 7, 5-min Apgar score below 4, intrapartum stillbirth and neonatal death < 28 days of age).ResultsAdverse outcome in vaginal preterm breech delivery was associated with maternal obesity (aOR 32.19, CI 2.97–348.65), smoking (aOR 2.29, CI 1.12–4.72), congenital anomalies (aOR 4.50, 1.56–12.96), preterm premature rupture of membranes (aOR 1.87, CI 1.00–3.49), oligohydramnios (28–32 weeks of gestation: aOR 6.50, CI 2.00–21.11, 33–36 weeks of gestation: aOR 19.06, CI 7.15–50.85), epidural anesthesia in vaginal birth (aOR 2.44, CI 1.19–5.01), and fetal growth below the second standard deviation (28–32 weeks of gestation: aOR 5.89, CI 1.00–34.74, 33–36 weeks of gestation: aOR 12.27, CI 2.81–53.66).ConclusionThe study shows that for each subcategory of preterm birth, there are different risk factors for adverse neonatal outcomes in planned vaginal breech delivery. Due to the extraordinary increased risk of adverse outcomes, we would recommend a planned cesarean section in very preterm breech presentation (28 + 0 to 32 + 6 weeks) with severe maternal obesity, oligohydramnios, or fetal growth restriction and in moderate to late preterm breech presentation (33 + 0 to 36 + 6 weeks) with oligohydramnios or fetal growth restriction.

Highlights

Around 4% of all fetuses are in breech presentation at birth [1, 2]
The royal college of obstetricians and gynaecologists stated in their breech delivery guidelines that a spontaneous vaginal breech labor in preterm pregnancies is not contraindicated if an immediate cesarean delivery is not needed for maternal or fetal reasons [16]
The only significant risk factor in a trial of vaginal breech labor emerging from our study was premature rupture of membranes (PPROM) (Table 1)

Summary

Introduction

Around 4% of all fetuses are in breech presentation at birth [1, 2]. In preterm labor breech presentation is more common than in term and every fourth of all fetuses born extremely preterm are in breech presentation at birth [3,4,5,6]. Breech presentation in preterm and term pregnancies is associated with obstetric risk factors for adverse neonatal outcomes, such as oligohydramnios, fetal growth restriction, and congenital anomalies [7,8,9]. In vaginal preterm breech delivery, the situation is still unclear in which cases a vaginal delivery is associated with an increased adverse neonatal outcome. Cochrane review 2013 could not recommend the mode of birth instead of another in preterm deliveries irrespectively of fetal presentation [20]

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Results

Conclusion