MONITORING UTERINE ACTIVITY

• US 20120150010A1
• Filed: 07/06/2010
• Published: 06/14/2012
• Est. Priority Date: 07/06/2009
• Status: Active Grant

• Current Assignee: Monica Healthcare Limited (General Electric Company)
• Original Assignee: Monica Healthcare Limited (General Electric Company)
• Inventors: Hayes-Gill, Barrie Robert, Pieri, Jean Francois
• Granted Patent: US 9,968,291 B2
• Time in Patent Office: Days
• US Class Current: 600/382
• CPC Class Codes: A61B 5/02411 of foetuses
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/391 of genito-urinary organs
• CPC Class Codes: A61B 5/4343 Pregnancy and labour monitoring, e.g. for labour onset detection
• CPC Class Codes: A61B 5/4356 Assessing uterine contractions A61B5/033 takes precedence
• CPC Class Codes: A61B 5/4362 Assessing foetal parameters
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured

Abstract

An apparatus and method for detecting uterine activity uses cutaneous electrodes on the maternal abdomen to obtain electrophysiological signals that can be used to obtain fetal and maternal heart rate. The apparatus includes a first input for receiving electrical signals from the cutaneous electrodes and a second input for receiving movement signals indicative of a movement of the maternal body from a movement detector. A signal processor separates a uterine electromyogram signal from fetal and maternal heart rate signals and filters out motion artefacts from the electromyogram using the movement signals. An output presents electrohysterogram (EHG) data from the uterine electromyogram signal.

Claims

1. Apparatus for detecting uterine activity comprising:

first input means configured to receive electrical signals from cutaneous electrodes;

second input means configured to receive movement signals indicative of a movement of the maternal body from a movement detector;

signal processing means configured to separate a uterine electromyogram signal from fetal and maternal heart rate signals in the electrical signals and to filter maternal motion artefacts from the uterine electromyogram using the movement signals; and

output means configured to present electrohysterogram (EHG) data from the uterine electromyogram signal.

2. The apparatus of claim 1 in which the signal processing means is configured to filter maternal motion artefacts from the electromyogram signal by attenuating the electromyogram signal as a function of the magnitude of the movement signals.

3. The apparatus of claim 1 in which the signal processing means is configured to filter fetal motion artefacts from the electromyogram signal by selective removal of peak excursions in the data based on an average value of the data.

4. The apparatus of claim 1 wherein the signal processing means is configured to attenuate or filter the electromyogram signal as a non-linear function of the magnitude of the movement signals.

6. The apparatus of claim 2 in which the EHG detection circuit includes a bandpass filter between 0.2 Hz and 0.9 Hz.

7. The apparatus of claim 1 in which the signal processing means is configured to remove baseline wander by:

for every specific data point, determining a minimum value from a set of preceding data points to act as a “

baseline value” and

subtracting that baseline value from the specific data point.

8. The apparatus of claim 1 in which the signal processing means is further configured to scale the EHG data with a non-linear function to provide a measure of contraction strength.

9. The apparatus of claim 8 in which the non-linear function is configured to return EHG data that correlates with intrauterine pressure measurements.

10. The apparatus of claim 1 further including a pair of electrodes for providing said electrical signals, coupled to the first input means, the electrodes configured for attachment to the maternal abdominal wall.

11. The apparatus of claim 10 in which at least one of the electrodes incorporates a movement sensor.

12. The apparatus of claim 11 in which the movement sensor is an accelerometer.

13. The apparatus of claim 11 in which the movement sensor detects movement or acceleration in three dimensions.

14. The apparatus of claim 1 in which the movement signals are derived from an amplitude of maternal ECG as a function of time, the signal processing means being configured to measure maternal ECG as a function of time and determine movement of the maternal body therefrom.

5. The apparatus of claim 5 in which the signal processing means includes an EHG detection circuit with a bandwidth between approximately 0.2 Hz and 150 Hz.

15. A method of detecting uterine activity comprising the steps of:

generating electrical signals from cutaneous electrodes disposed on a maternal abdomen;

obtaining movement signals indicative of a movement of the maternal body;

separating a uterine electromyogram signal from fetal and maternal heart rate signals in said generated electrical signals and filtering maternal motion artefacts from the uterine electromyogram signal using the movement signals; and

providing electrohysterogram (EHG) data from the uterine electromyogram signal.

16. The method of claim 15 further including the steps of:

attaching a first electrode to the symphis pubis region of the maternal abdomen;

attaching a second electrode to the maternal abdomen, between a line 5 cm below the uterus fundus and the line of the uterus fundus or between a line at the level of the navel or umbilicus and the line of the uterus fundus;

generating said electrical signals from said first and second electrodes.

17. The method of claim 15 further including the step of obtaining said movement signals from a movement transducer or sensor.

18. The method of claim 15 further including the step of obtaining said movement signals from said electrical signals generated by the cutaneous electrodes.

19. Apparatus for detecting uterine activity comprising:

input means configured to receive electrical signals from cutaneous electrodes;

signal processing means configured to separate a uterine electromyogram signal from fetal and maternal heart rate signals in the electrical signals and to filter foetal motion artefacts from the uterine electromyogram; and

output means configured to present electrohysterogram (EHG) data from the uterine electromyogram signal.

20. The apparatus of claim 19 in which the signal processing means is configured to filter fetal motion artefacts from the electromyogram signal by selective removal of peak excursions in the data based on an average value of the data.

21. A method of detecting uterine activity comprising the steps of:

generating electrical signals from cutaneous electrodes disposed on a maternal abdomen;

separating a uterine electromyogram signal from fetal and maternal heart rate signals in said generated electrical signals and filtering foetal motion artefacts from the uterine electromyogram; and

providing electrohysterogram (EHG) data from the uterine electromyogram signal.

22. The method of claim 21 in which the fetal motion artefacts are filtered from the electromyogram signal by selective removal of peak excursions in the data based on an average value of the data.

23. An integrated electrode and movement sensor for attachment to a maternal abdomen configured to generate electromyogram signals from the maternal body and movement signals indicative of a movement of the maternal body, the electrode comprising:

an electrical contact portion for establishing electrical contact with the skin of the abdomen;

attachment means for securing the integrated electrode and movement sensor to the body; and

a transducer configured to generate movement signals indicative of movement of the maternal body.

24. Apparatus for collecting fetal heart rate data and uterine activity data, comprising:

means for receiving, from sensors disposed on the abdomen of a pregnant mother, electrical signals indicative of fetal heart rate and uterine activity;

means for processing said signals to obtain at least one fetal heart rate parameter and at least one uterine activity parameter; and

means for providing as output a graphical or tabular form of said at least one fetal heart rate parameter and said at least one uterine activity parameter for timed frames.

25. The apparatus of claim 24 in which:

the fetal heart rate parameter is selected to include at least one of baseline heart rate, heart rate variability, beat-to-beat time interval, RMSSD of beats time intervals, number of heart rate accelerations and number of heart rate decelerations; and

the uterine activity parameter is selected to include at least one of contraction time location, contraction duration, contraction strength and time occurrence from a fetal heart rate deceleration.

26. The apparatus of claim 24 configured to provide said output in respect of timed frames having a duration of at least 30 minutes and long-term collection and output of said parameters over a period of at least one hour.