Intended for healthcare professionals


Electronic fetal monitoring, cerebral palsy, and caesarean section: assumptions versus evidence

BMJ 2016; 355 doi: (Published 01 December 2016) Cite this as: BMJ 2016;355:i6405
  1. Karin B Nelson, scientist emeritus1,
  2. Thomas P Sartwelle, attorney2,
  3. Dwight J Rouse, academic obstetrician3
  1. 1National Institute of Neurological Disorders and Stroke, Bethesda, MD, 20892, USA
  2. 2Deans and Lyons, Houston, TX, USA
  3. 3Women and Infants’ Hospital of Rhode Island and Brown University, Providence, RI, USA
  1. Correspondence to: K B Nelson nelsonk{at}

Given evidence that cerebral palsy is not reduced by electronic fetal monitoring, Karin Nelson, Thomas Sartwelle, and Dwight Rouse ask why routine monitoring and related litigation continue to contribute to high rates of caesarean births

A third of babies born in the United States,1 and a quarter in England,2 are delivered by caesarean section. Rates of caesarean have risen substantially since the 1970s, and current rates exceed the optimum to minimise mortality and morbidity of mothers and infants.3

An important driver of the rising rate of operative deliveries is the use of continuous electronic fetal monitoring (cardiotocography) in labour. It was introduced to enable early identification of fetal asphyxia in the hope of preventing death or long term neurological morbidity, especially cerebral palsy. However, it has a high false positive rate and has not been shown to reduce cerebral palsy.4 We examine the evidence on its effectiveness and some unintended consequences of its use.

Electronic fetal monitoring and cerebral palsy

Cerebral palsy was once thought to be caused mainly by birth asphyxia. Early advocates of electronic fetal monitoring expected that early detection of asphyxia in labour would largely eliminate cerebral palsy. Studies using surrogate endpoints such as low neonatal pH and low Apgar scores encouraged that expectation. Although it was initially developed for use in births in which the fetus was thought to be at increased risk, electronic monitoring soon became a standard intervention in obstetrics. Clinical trials were not conducted before monitoring was introduced because it was considered unethical to deny the expected benefits to controls.5

Only two randomised trials, both published more than 25 years ago, have compared cerebral palsy rates in births monitored electronically or by intermittent auscultation. Cerebral palsy cannot be diagnosed at birth, so infants have to be followed for several years, until a …

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