Feasibility Study: Continuous Fetal Monitoring During Maternal Exercise

The Nemo Fetal Monitoring Sytem (Nemo Healthcare B.V., Veldhoven, the Netherlands) will be used for electrophysiological monitoring.

• Electrophysiological monitoring (Device): electrofysiological CTG monitoring with the Nemo Fetal Monitoring System (Nemo Healthcare B.V., Veldhoven, the Netherlands). The NFMS consists of a wireless and beltless electrode patch on the maternal abdomen. It monitors fetal heart rate by fetal electrocardiography, maternal heart rate by maternal electrocardiography and the electrical activity of the uterine muscle by electrohysterography.

Primary outcomes

• Success rate of continuous electrophysiolgoical monitoring during maternal exercise [15 minutes (min) before, 30 min during and 15 min after maternal exercise]: Defined as the percentage of time during continuous maternal exercise with concurrent signal output of the fetal heart rate. Continous electrophysiological monitoring is feasible by a successrate of =>80%

Secondary outcomes

• Maternal heartrate [15 min before, 30 min during and 15 min after maternal exercise]: Mean maternal heart rate in beats per minutes (bpm) from cardiotocogram
• Mean maternal heartrate [15 min before, 30 min during and 15 min after maternal exercise]: Mean maternal heart rate in bpm from cardiotocographic output
• Fetal heart rate variability [15 min before, 30 min during, 15 min after exercise]: Fetal heart rate variability from cardiotocogram, measured as average short term variability and average long term variability
• Fetal heart rate [15 min before, 30 min during and 15 min after maternal exercise]: Mean fetal heart rate in bpm from cardiotocogram
• Contraction frequency [15 min before, 30 min during and 15 min after maternal exercise]: Mean contraction freqency from cardiotocogram, defined as the number of contractions per 10 minutes.
• Contraction duration [15 min before, 30 min during and 15 min after maternal exercise]: Mean contraction duration in seconds from cardiotocogram
• Contraction intensity [15 min before, 30 min during and 15 min after maternal exercise]: Mean maximum contraction intensity (i.e. amplitude) from cardiotocogram (in arbitrary units)
• Contraction interval [15 min before, 30 min during and 15 min after maternal exercise]: Mean contraction interval in seconds, from cardiotocogram
• Accelerations [15 min before, 30 min during and 15 min after maternal exercise]: Increase in the fetal heart rate above the baseline lasting 10-120 seconds and reaching a peak of at least 10 seconds, from cardiotocogram
• Decelerations [15 min before, 30 min during and 15 min after maternal exercise]: Decrease in fetal heart rate under the baseline lasting at 15 seconds, and with a minimum amplitude of 15 seconds, from cardiotocogram.
• Signal loss [15 min before, 30 min during and 15 min after maternal exercise]: Percentage of fetal heart rate signals values under 35bpm, from cardiotocogram
• Maternal satisfaction of continuous fetal monitoring and tolerability of the patch during exercise [Directly after exercise (duration to complete: 10 min)]: Maternal satisfaction by selfmade questionnaire

Sex: Female, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Minimal age of 18 years old
* Pregnant women with an uncomplicated singleton pregnancy and a gestational age between 30+0 and 40+0 weeks and days
* Oral and written informed consent is obtained
* Engage in aerobic exercise during pregnancy

A potential subject who meets any of the following criteria will be excluded from participation in this study:

* Insufficient knowledge of Dutch or English language
* Women with a multiple pregnancy
* Contra-indications for the Nemo Fetal Monitoring System (NFMS):

  * Fetal and/or maternal cardiac arrhythmias
  * Contraindications to abdominal placement (dermatologic diseases of the abdomen precluding preparation of the abdomen with abrasive paper)
  * Women connected to an external or implanted electrical stimulator, such as a pacemaker (because of disturbance of the electrophysiological signal)
* Fetus with known congenital or chromosomal abnormalities
* Women with absolute or relative contraindications to aerobic exercise during pregnancy at time of inclusions and during maternal exercise:

  * Mild or severe respiratory diseases (e.g. chronic obstructive pulmonary disease, restrictive lung disease and cystic fibrosis)
  * Mild or severe acquired or congenital heart disease with exercise intolerance
  * Uncontrolled or severe arrhythmia
  * Vasa previa
  * Type 1 diabetes
  * IUGR
  * Severe PE
  * Cervical insufficiency
* Women with relative contraindications to aerobic exercise during pregnancy:

  * Mild respiratory disorders
  * Mild congenital or acquired heart disease
  * Well-controlled type 1 diabetes
  * Pre-eclampsia
  * Cervical insufficiency
  * Placenta previa
  * Untreated thyroid disease
  * Symptomatic, severe eating disorder
  * Multiple nutrient deficiencies and/or chronic undernutrition
  * Moderate-heavy smoking (> 20 cigarettes per day)

• Simone Goossens, PhD, Principal investigator, Principal Investigator