Monitoring the baby's heart using electrocardiography (ECG) plus cardiotocography (CTG) during labour provides some modest help for mothers and babies when continuous monitoring is needed.
Strong uterine contractions during labour reduce the flow of maternal blood to the placenta. The umbilical cord may also be compressed during labour, especially if the membranes are ruptured. Usually the baby has sufficient reserve to withstand this effect but some may become distressed. Electronic heart monitoring may be suggested if the doctors think the baby is not getting enough oxygen during labour. Two different methods may be used. CTG measures the baby's heart rate together with the mother's uterine contractions. An ECG measures the heart's electrical activity and the pattern of the heart beats. This involves an electrode being passed through the woman's cervix and attached to the baby's head. This review of six randomised controlled trials, including a total of 16,295 women, found that monitoring the baby using ECG plus CTG resulted in fewer blood samples needing to be taken from the baby's scalp, and less surgical assistance with the birth, than with CTG alone. There was no difference in the number of caesarean deliveries and little to suggest that babies were in better condition at birth.