Physiological cardiotocography interpretation and neonatal morbidity: A historical pre–post cohort study in a tertiary perinatal center

INTRODUCTION: Cardiotocography (CTG) interpretation is prone to inter-observer variability and may contribute to both missed fetal compromise and potentially avoidable intrapartum intervention. Physiological CTG interpretation (PCI) reframes fetal surveillance around fetal physiology and the intensity of hypoxic stress, but real-world outcome data after unit-wide implementation remain limited. MATERIAL AND METHODS: Historical pre-post cohort study with case-mix adjustment at University Hospital Ulm, a tertiary perinatal center in Germany (~3200 births/year). We included term singleton pregnancies (≥37 + 0 weeks) with intended vaginal birth, comparing a pre-implementation period (January 01-December 31, 2018) with a post-implementation period after full adoption (May 01, 2022-April 30, 2023). PCI was introduced as a multicomponent implementation strategy (training, bedside facilitation, documentation changes, and sustainment). PRIMARY OUTCOME: composite neonatal morbidity defined as neonatal unit (NNU) transfer plus ≥1 of: umbilical artery pH 16 mmol/L, or 5-min Apgar score