Uterine activity monitoring during labour – A multi-centre, blinded two-way trial of external Tocodynamometry against Electrohysterography

Objective: To determine the quality of intrapartum uterine activity (UA) monitoring in daily practice during the first and second stage of labour. The total duration of inadequate UA monitoring is quantified in relation to the technique applied namely, external tocodynamometry (TOCO) or Electrohysterography (EHG).

Study design: One hundred and fourty-four UA recordings, collected from 1st September 2008 until 15th October 2009 from deliveries at the Marien-Hospital Witten, Germany, were analyzed by obstetricians based at different centres. Included recordings were from singleton and simultaneously with external TOCO and EHG monitored pregnancies. The last two hours of the first stage or the last two hours of recording before in-labour Casaerean section and the complete second stage were evaluated. External TOCO and EHG UA recordings were blinded and assessed by their quality via four independent gynaecologists’ opinions in terms of: “adequate”, a recognizable and reliable UA pattern during the complete registration, or “inadequate”. The number of uterine contractions was also counted by the four gynaecologists. Statistical analysis were performed with the Wilcoxon signed ranks test.

Results: The overall EHG signal showed significantly more “adequate” UA trace (average length of UA recordings mean 138.8±SD 110.9 minutes) when compared to the TOCO (mean 119.6±99.6 minutes) [p < 0.001]. All doctors evaluated the UA assessment as “easier” (p < 0.001) using the EHG compared with TOCO. More variability was observed with TOCO contraction count when compared to EHG.

Conclusion: Intrapartum UA monitoring in daily practice via the EHG mode provides a more recognizable UA trace than the TOCO.

electrohysterography - uterine activity monitoring - tocography - quality - labour