A large study explored the safety of different cardiotocography (CTG) monitoring practices —methods of monitoring a fetus during labor — in clinical settings. It compared different fetal surveillance methods and their association with adverse short- and long-term fetal and neonatal outcomes.The study expanded upon existing reports suggesting that CTG monitoring of fetal heart rate (FHR) by an abdominal external ultrasound transducer without simultaneous maternal heart rate recording is associated with increased risk of early neonatal death and other asphyxia-related neonatal outcomes.
Three methods were studied: The cohort was divided into three groups according to the method of CTG monitoring used at birth: women with an ultrasound transducer; women with both an ultrasound transducer and a maternal heart rate transducer using Philips solution; and women with an internal fetal scalp electrode.
There are drawbacks of just using external ultrasound transducer monitoring: The use of external fetal monitoring without simultaneous maternal heart rate monitoring increased the risk of neonatal complications.
There is increased independent risk of asphyxia-related neonatal outcomes for fetuses of mothers monitored during labor by external ultrasound transducer alone, compared with fetuses of mothers who also have maternal heart rate (MHR) recording or internal fetal scalp monitoring.
Education is needed: Clinicians and midwives should be aware of the effect of ultrasound transducer alone for fetal heart rate monitoring on potential adverse outcomes.
Clinical implications: “Our findings define that external FHR monitoring without a safeguard of simultaneous MHR recording is associated with increased risk of intrapartum fetal hypoxia, which can be detected as asphyxia-related fetal and neonatal outcomes at birth,” write the authors.
Intrapartum CTG with simultaneous maternal heart rate registration improves neonatal outcome