Intrapartum monitoring with cardiotocography and ST-waveform analysis in breech presentation: an observational study

ObjectiveTo determine the electrocardiographic performance and neonatal outcome of pregnancies with breech presentation and planned vaginal delivery monitored with ST-waveform analysis (STAN). DesignProspective observational study. SettingUniversity hospital, Norway; 2004-2008. PopulationSingleton pregnancies with a gestational age above 35+6weeks, breech presentation, selected for vaginal delivery and monitored with STAN. MethodsCommon clinical guidelines for STAN monitoring were used. An experienced neonatologist graded the symptoms of neonatal encephalopathy. The outcome was compared with STAN-monitored high-risk deliveries in a vertex presentation (n=5569) using logistic regression analysis. Main outcome measureFrequency of ST events, indications of intervention for fetal distress, and neonatal morbidity and mortality. ResultsBreech presentation occurred in 750 of 23219 (3.2%) deliveries, 625 (83%) of which were selected for vaginal delivery. Intrapartum monitoring by STAN was performed in 433 (69%). Compared with vertex presentations, fetuses in breech presentation had a lower risk of baseline T/QRS rise during labour [odds ratio (OR)=0.7, 95% confidence interval (95% CI)=0.7-0.9, P=0.003] and a higher risk for intervention as a result of preterminal cardiotocogram (OR=2.9, 95% CI=1.6-5.9, P=0.001). The risks of perinatal mortality (OR=1.8, 95% CI=0.2-15, P=0.6), cord metabolic acidosis (OR=0.8, 95% CI=0.2-3.2, P=0.7) and moderate or severe neonatal encephalopathy (OR=1.8, 95% CI=0.5-6.2, P=0.3) did not differ significantly between breech and vertex deliveries. ConclusionSTAN can be used for the surveillance of breech presentations selected for vaginal delivery with an acceptable neonatal outcome. The electrocardiogram (ECG) pattern during labour varies with the fetal presentation.