... There have been a handful of small studies ... that looked at the effectiveness of fetal heart rate monitors, but none of them were large enough to be conclusive.
Chauhan and his colleagues ... used a sample of 1,945,789 singleton infant birth and death records ... Multivariable log-binomial regression models were fitted to estimate risk ratio to evaluate the association between electronic fetal heart rate monitoring (EFM) and mortality ...
... 89% of singleton pregnancies had EFM. EFM was associated with significantly lower infant mortality (adjusted RR 0.75; 95% CI 0.69, 0.81); this was mainly driven by the lower risk of early neonatal mortality (adjusted RR 0.50; 95% CI 0.44, 0.57) associated with EFM. In low-risk pregnancies, EFM was associated with decreased risk for low (< 4) 5 min Apgar scores (RR 0.54; 95% CI 0.49, 0.51), whereas in high risk pregnancies EFM was also associated with decreased risk of neonatal seizures (adjusted RR 0.65; 95% CI 0.46, 0.94).
The study demonstrates that the use of EFM decreased early neonatal mortality by 53%.
The authors have not pointed to the increased intervention that may have been used to prevent these adverse outcomes. EFM in itself does not save lives; EFM is merely the prompt that alerts health practitioners to take further action. This action is usually in the form of intervention to hasten birth. I was surprised that in this study, 89% women had EFM. Most pregnancies are considered to be low-risk and therefore not in need of EFM. The alternative - intermittent auscultation - was not defined. In NSW, the policy is to intermittently listen in for the baby's heart beat every 15 minutes after a contraction, and to listen for a full minute. Under this policy, women are able to be upright and mobile for their labours and births and this has a positive impact on the woman's experience of birth.