Intrapartum CTG Registration: the mother's heart rate (green curve) recorded together with the fetal heart rate (upper blue curve). Mikko Tarvonen


A comprehensive Finnish study has revealed that monitoring the mother's heart rate during childbirth, alongside the fetus's heart rate, significantly reduces the risk of brain damage in newborns. This finding challenges the widespread use of external fetal heart rate monitoring alone, which can sometimes miss signs of fetal distress due to oxygen deprivation if the mother's heart rate is not concurrently tracked. This oversight can lead to the fetus's distress condition remaining undetected, as the fetal heart rate might be confused with the mother's during monitoring.

The study, conducted by a research team from the University of Helsinki and HUS Helsinki University Hospital, has been published in the prestigious American Journal of Obstetrics and Gynecology. It analyzed data from nearly 214,000 spontaneous full-term births in hospitals in the HUS area from 2005 to 2023, making it the largest dataset of its kind ever published.

Findings indicate that newborns monitored solely with external heart rate monitoring had a 1.6 times higher risk of brain damage and a 2.3 times higher risk of severe fetal blood acidosis compared to those monitored with an internal sensor attached to the fetus's scalp or by combining external fetal monitoring with maternal heart rate monitoring. This risk highlights the critical need for simultaneous monitoring of both mother and fetus during labor, especially during the pushing phase of delivery when the mother's heart rate typically increases, and the fetus's heart rate may show periodic slowing.

"In particular, during the pushing phase of delivery, the mother's heart rate typically increases, whereas the fetal heart rate may show periodic slowing. This can easily lead to confusion between the fetal and maternal heart rates, leaving signs of fetal oxygen deprivation unnoticed," explained researcher Mikko Tarvonen, outlining the challenges of external cardiotocography (CTG) registration.

The HUS region has already adopted safer practices by requiring simultaneous maternal heart rate monitoring during childbirth since 2019. This shift towards more comprehensive monitoring practices reflects a growing recognition of their importance in ensuring the safety and well-being of both mother and child during delivery.

The study compared the safety of external fetal heart rate monitoring combined with maternal heart rate monitoring and internal fetal monitoring, finding both methods equally safe in terms of the incidence of brain damage. However, internal monitoring proved to be the safest in terms of minimizing complications related to fetal oxygen deprivation.

This research underscores the need for updated guidelines that recommend the incorporation of maternal heart rate monitoring during labor to better detect and prevent fetal distress, potentially leading to a significant reduction in newborn brain damage and other complications related to oxygen deprivation.