Antenatal electrophysiological cardiotocography in preterm gestations. An observational study to test the performance of a new device for fetal monitoring.

Rationale: Traditionally, the antenatal CTG is performed with two transducers placed on the mother’s abdomen: one to monitor the FHR by Doppler ultrasound (DU) and the other at the uterine fundus to measure (frequency of) contractions by tocodynamometry (TOCO). Recently, it has become possible to perform CTG non-invasively through electrophysiology, by the Nemo Fetal Monitoring System (NFMS). This system is CE marked in 2018 for gestations of 21 weeks till childbirth. Data obtained with predecessor hardware in 2007 show a fall of success rate to 60% for identifying fetal QRS complexes by electrophysiology for the period from 27 to 36 weeks. Hardware changes have been made in the new NFMS in 2018.

Objective: The aim of this observational study is to evaluate the quality and interpretability of the CTG tracings made by NFMS (2018) at gestational ages of 24 to 36 weeks.

Study design: Observational study.

Study population: In total 42 pregnant women who visit the outpatient clinic or are hospitalized in Zuyderland hospital will be asked for voluntary participation.

Intervention (if applicable): In total 72 CTGs will be made. In 36 patients, 1 CTG obtained by electrophysiology of 30 minutes is made. In 6 patients, 6 CTGs will be made at intervals of 2 weeks gestation.

Main study parameters/endpoints: Quality and Interpretability (judged by three independent obstetricians).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Thirthy-six patients will be measured 30 minutes, including preparation 40 minutes. Six patients will be measured 6 times, in total 6 x 40 minutes. Acquiring the CTG by NFMS carries virtually no risks. In less than 5% a temporarily redness of the skin of the abdomen appears, that will spontaneously disappear within 24 hours after the measurement.

The performance of the NFMS in the premature period will be enhanced due to changes in the algorithm compared to traditional CTG.

1 registration between 24 -36 weeks of gestation. In 6 patients 6 registrations in this time period with an interval of 2 weeks.