Comparison of the T/QRS ratio of the fetal electrocardiogram and the fetal heart rate during labour and the relation of these variables to condition at delivery

The T/QRS ratio of the fetal electrocardiogram (ECG) was recorded to within 30 min of delivery from 105 women in labour. There were no significant differences in the mean T/QRS ratio in the last hour of record between those with normal and intermediate, or abnormal fetal heart rate (FHR) patterns. In 66 labours the mean T/QRS ratio in the first hour of record was compared with that of the last hour; the only significant change was a small decrease in the mean ratio from 11% to 7% in a group of 11 fetuses with an abnormal FHR pattern throughout the recording time. Eight babies were born with evidence of acidosis (umbilical artery pH less than or equal to 7.16), and another four were born in poor condition (1 min Apgar score less than 4) without evidence of acidosis; none had a mean last hour T/QRS ratio significantly different from the previously established normal range.