Stethoscopes Superior for Intrapartum Fetal Surveillance

Stethoscope intermittent auscultation (IA) remains the best method for determining fetal distress during labor and delivery, according to a new study.

Researchers at the University of Warwick (Coventry, United Kingdom), the University of Birmingham (UB; United Kingdom), and other institutions undertook a systematic review and meta-analysis of published studies to evaluate the effectiveness of different types of intrapartum fetal surveillance. In all, 33 relevant studies were identified, involving 118,863 patients. The main focus of the review was on intrapartum emergency cesarean deliveries and other secondary maternal and neonatal outcomes.

The results showed that IA reduced the risk for emergency cesarean deliveries versus other types of surveillance, including cardiotocography (CTG), CTG with fetal scalp pH analysis (FBS), CTG with fetal scalp lactate, CTG with fetal pulse oximetry (FPO), and CTG with FBS and FPO. The results were similar for reduction in cesarean deliveries for fetal distress. However, there was no reduction in risk noted for neonatal acidemia, neonatal unit admissions, Apgar scores, or perinatal death for any of the evaluated methods. The study was published on April 6, 2021, in Journal of the Canadian Medical Association (CMAJ).

“Our analysis suggests that all additional methods introduced to improve the accuracy of electronic fetal heart monitoring have failed to reduce the risk of adverse neonatal or maternal outcomes beyond what IA achieved 50 years ago,” concluded lead author Bassel Al Wattar, PhD, of the University of Warwick, and colleagues. “Newer fetal surveillance methods did not improve neonatal outcomes or reduce unnecessary maternal interventions. Further evidence is needed to evaluate the effects of fetal pulse oximetry and fetal heart electrocardiography in labor.”

Monitoring the fetal heart rate to detect intrapartum hypoxia using simple surveillance techniques, such as the Pinard stethoscope, has been practiced for decades. CTG remains the most common surveillance method used in high-risk pregnancies; however, many researchers have evaluated its use in combination with other methods, such as fetal heart electrocardiogram, FBS, or fetal pulse oximetry (FPO) to improve its diagnostic value. However, the effectiveness of such methods in improving maternal and neonatal outcomes remains debatable, as stillbirth rates have plateaued worldwide, while cesarean delivery rates continue to rise.

Related Links:
University of Warwick
University of Birmingham