SYSTEM AND METHOD FOR PRECISE DETERMINATION OF A DATE OF CHILDBIRTH WITH A WEARABLE DEVICE

Abstract

The invention relates to an electronic system (5) for determining a date of childbirth by analysing vascular activity of a pregnant person during pregnancy, the system comprising at least the following components: A wearable device (1) including a first sensor system (101) configured to be worn in contact with the skin of the pregnant person, wherein the wearable device (1) is further configured to detect vascular activity, such as heartbeats of the pregnant person, and to provide sensor signals indicative for the detected vascular activity; An analysing module (13, 30, 40) configured and arranged to process the sensor signals of the first sensor system (101), wherein the analysing module (13, 30, 40) is configured and arranged to determine from the sensor signals a date of childbirth. The invention further relates to a method for determining a date of childbirth by analysing vascular activity of a pregnant person.

Claims

1. An electronic system for determining a date of childbirth by analysing vascular activity of a pregnant person during pregnancy, the system comprising: a wearable device including a first sensor system configured to be worn in contact with the skin of the pregnant person, wherein the wearable device is further configured to detect vascular activity, including a heart rate of the pregnant person, and to provide sensor signals indicative of the detected vascular activity; and an analysing module configured and arranged to process the sensor signals of the first sensor system, wherein the analysing module is configured and arranged to determine from the sensor signals of the first sensor system a date of childbirth by determining from the sensor signals, the heart rate, and an onset of a period of a decreasing heart rate of the pregnant person.

2. The electronic system according to claim 1, wherein the analysing module is configured and arranged to determine from the sensor signals of the first sensor system a date of childbirth by determining and evaluating a feature of the vascular activity from the sensor signals of the first sensor system.

3. The electronic system according to claim 1, wherein the period of a decreasing heart rate is a period of a decreasing heart rate in the third trimester of the pregnancy of the pregnant person.

4. The electronic system according to claim 1, wherein the wearable device comprises a second sensor system configured to detect a second parameter other than the vascular activity of the pregnant person, and wherein the analysing module is configured to process sensor signals of the second sensor system, wherein the analysing module is further configured and arranged to determine the date of childbirth from the sensor signals of the first sensor system and the second sensor system.

5. The electronic system according to claim 4, wherein the second sensor system is configured and arranged to detect an acceleration of the wearable device, wherein the second sensor system comprises an accelerometer.

6. The electronic system according to claim 5, wherein the analysing module is configured to detect sleep phases of the pregnant person by determining and evaluating a heart rate variability from the sensor signals of the first sensor system and/or by evaluating the acceleration determined by the second sensor system.

7. The electronic system according to claim 6, wherein the electronic system comprises a data storage system, wherein the electronic system is configured and arranged to store the sensor signals and/or the determined heart rate and or the heart rate variability of the pregnant person in the data storage system.

8. The electronic system according to claim 7, wherein the analysing module is configured and arranged to determine the date of childbirth by evaluating the sensor signals, the determined heart rate, and/or the heart rate variability stored in the data storage system, by determining the onset of the period of a decreasing heart rate from the stored data.

9. The electronic system according to claim 2, wherein the analysing module is configured and arranged to compare a temporal course of the determined feature of the vascular activity to model data and to determine from said comparison a date of childbirth.

10. The electronic system according to claim 1, wherein the analysing module is configured and arranged to determine the date of childbirth based at least in part on the onset of the period of a decreasing heart rate from sensor signals acquired during sleep phases of the pregnant person.

11. The electronic system according to claim 1, wherein the analysing module is configured and arranged to determine the date of childbirth from the sensor data comprising the lower 10.sup.th percentile of the heart rates acquired during sleep phases of the person.

12. A method for determining a date of childbirth comprising the steps of: detecting a vascular activity of a pregnant person; providing sensor signals indicative for the detected vascular activity; determining an onset of a period of decreasing heart rate, particularly in the third trimester of pregnancy from the sensor signals; and predicting the date of childbirth from the determined onset of the period decreasing heart rate.

13. The method according to claim 12, wherein the method further comprises the steps of determining the date of childbirth from sensor signals acquired during sleep phases of the pregnant person.

14. The method according to claim 13, wherein the sleep phases of the pregnant person are determined by evaluating a heart rate variability and/or sensor signals indicative of a resting state pregnant person, wherein the sensor signals include acceleration.

15. The method according to claim 12, wherein the method is executed on the electronic system comprising a wearable device including a first sensor system configured to be worn in contact with the skin of the pregnant person, and an analysing module configured and arranged to process the sensor signals of the first sensor system.

Description

[0117] Particularly, exemplary embodiments are described below in conjunction with the Figures. The Figures are appended to the claims and are accompanied by text explaining individual features of the shown embodiments and aspects of the present invention. Each individual feature shown in the Figures and/or mentioned in said text of the Figures may be incorporated (also in an isolated fashion) into a claim relating to the device according to the present invention.

[0118] FIG. 1: shows a schematic illustration of an electronic system according to the invention for detecting the heart rate and further parameters related to the pregnancy of a person, the electronic system comprising a wearable device, in particular a wrist-worn bracelet, with an analysing module comprising a processor in the wearable device and/or in an external system.

[0119] FIG. 2: shows a flow diagram schematically illustrating an exemplary sequence of steps for determining the date of childbirth by analysing the heart rate during pregnancy.

[0120] FIG. 3: shows a line graph illustrating the 10.sup.th percentile of a heart rate distribution referenced to a heart rate prior conception (weeks −10 to 0) for of a group of pregnant women over the weeks of pregnancy. The data is grouped according to the delivery date in: deliveries before 37 weeks (indicated by a line with a plus sign “+”), deliveries between 37-38 weeks (indicated by a line with solid circles), deliveries between 39-40 weeks (indicated by a line with solid squares) and deliveries later than 41 weeks (indicated by a line with “x”) of pregnancy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0121] FIG. 1 shows an electronic system 5 for detecting a change in a vascular activity, such as the heart rate. The electronic system 5 comprises a wearable device 1 and an analysing module comprising one or more processors 13, 30, 40 in the wearable device 1 and/or in an external system. Reference number 3 refers to a computer system, e.g. a server, a cloud-based system, comprising one or more computers 31 with one or more processors 30 and one or more data storage systems 31. The computer system 3 or its processors 30, respectively, are connected to the data storage system 31 and configured to execute various functions, as will be explained in more detail. The data storage system 31 for example comprises a RAM, a flash memory, hard disks, data memory, and/or other data storages.

[0122] In FIG. 1, reference numeral 4 refers to a communication device, in particular a mobile communication device, e.g. a mobile phone, a cellular telephone, a tablet or laptop computer, comprising one or more processors 40, a data storage 41, and data entry elements 42. The processors 40 are connected to the data storage 41 and configured to execute various functions, as will be explained in more detail. The data storage 41 comprises a RAM, a flash memory, a data memory, and/or other data storage. The data entry elements 42 for example comprise one or more keys, a keyboard, and/or a touch sensitive screen enabling the user to enter data and/or event indications.

[0123] In FIG. 1, reference number 1 refers to a wearable device, e.g. a wrist wearable device, specifically a wrist wearable electronic device. Reference numeral 1A refers to a cross-sectional view of the wearable device 1 along central axis A. The wearable device 1 includes a fixation system for attaching the wearable device 1 on the body of a user, specifically, for attaching the wearable device 1 and particularly the first sensor system 101 in contact with the skin of the user, such that heart beats can be detected by the first sensor system 101; in the embodiment shown in FIG. 1, the wearable device 1 comprises a wrist band 11 and a device body 10 attached to or integrated in the wrist band 11. The wristband 11 is implemented as a watchstrap, a watchband, a bracelet, a cuff, or the like. The device body 10 comprises a housing 15 and an optional display 16 integrated in the housing 15.

[0124] As illustrated schematically in FIG. 1, the wearable device 1 comprises several sensor systems 100, including the first sensor system 101 with optical sensors configured to generate photoplethysmography (PPG) signals for measuring heart signals, heart rate, heart rate variability, perfusion, and breathing rate. For example, sensor system 101 comprises a PPG-based sensor system for measuring heart signals, heart rate and heart rate variability as described in Simon Arberet et al., “Photoplethysmography-Based Ambulatory Heartbeat Monitoring Embedded into a Dedicated Bracelet”, Computing in Cardiology 2013; 40:935-938, included herewith by reference in its entirety.

[0125] In an embodiment, the sensor systems 100 further include a second sensor system 102 with one or more accelerometers for measuring body movements (acceleration).

[0126] In an embodiment, for the purpose of sleep phase analysis the accelerometers are implemented in combination with the PPG-based sensor system, as described in Philippe Renevey et al., “Photoplethysmography-based bracelet for automatic sleep stages classification: Preliminary Results,”, IASTED 2014, Zurich, Switzerland, included herewith by reference in its entirety.

[0127] The sensor systems 100 further include a temperature sensor system 104 for measuring the user's temperature; specifically, the user's skin temperature; more specifically, the wrist's skin temperature. The temperature sensor system 104 comprises one or more sensors, including at least one temperature sensor and in an embodiment one or more additional sensor(s) for measuring further parameters like a perfusion, a bio-impedance and/or a heat loss for determining the user's temperature.

[0128] Depending on the embodiment, the sensor systems 100 further can include a bio-impedance sensor system 103 with an electric impedance or conductance measuring system. The optical sensors 101, the bio-impedance sensor system 103, and the temperature sensor system 104 are integrated in a housing 15 of the wearable device 1 and are arranged on a rear side 150 of the wearable device 1, e.g. opposite of an optional display 16 of the wearable device 1, facing the user's skin in a mounted state of the wearable device 1. In the mounted state, when the device 1 is actually attached and worn, e.g. on the wrist, just as one would wear a watch, the rear side 150 of the wearable device 1 or the rear side 150 of its housing 15, respectively, is in contact with the skin, e.g. the skin of the wrist, i.e. the optical sensors 101, the bio-impedance system 103, and the temperature sensor system 104 touch the skin or at least face the skin, e.g. the skin of the wrist.

[0129] The wearable device 1 further comprises a data storage 12, e.g. a data memory such as RAM or flush memory, and an operational processor 13 connected to the data storage 12 and the sensor systems 100. The processor 13 comprises an electronic circuit configured to perform various functions.

[0130] As illustrated in FIG. 1, in an embodiment, the wearable device 1 further comprises a communication module 14 connected to the processor 13. The communication module 14 is configured for data communication with an external system 3, 4, that is separated from the wearable device 1, i.e. a computerized system that is arranged in a different housing than the wearable device 1. Depending on the embodiment and/or configuration, the external system is a remote computer system 3 or a mobile communication device 4. Accordingly, the communication module 14 is configured for data communication with the remote computer system 3 via a network 2 and/or with the mobile communication device 4 e.g. via a close range communication interface. The network 2 comprises a mobile radio network such as a GSM-network (Global System for Mobile communication), a UMTS-network (Universal Mobile Telephone System), or another mobile radio telephone system, a wireless local area network (WLAN), and/or the Internet. For example, for close range communication, the communication module 14 comprises a Bluetooth communication module, e.g. a Low Energy Bluetooth module, or another close range communication module configured for direct data communication with the external mobile communication device 4. In an alternative embodiment, the mobile communication device 4 is configured to facilitate the data communication between the wearable device 1 and the remote computer system 3, e.g. by relaying the measurement data from the wearable device 1 via the network 2 to the remote computer system 3, for processing. Although not illustrated, the wearable device 1 further comprises a timer module configured to generate current time and date information, e.g. a clock circuit or a programmed timer module. The timer module is further configured to generate time stamps including the current time and date. As further illustrated in FIG. 1, the wearable device 1 further comprises one or more data entry elements 18 enabling the user to enter data and/or event indications. Depending on the embodiments, data entry elements 1B comprise data entry buttons, keys and/or rotary selection switches.

[0131] In FIG. 2 box 200 relates to physiological parameters and other factors, including vascular activity and body movement of the pregnant person, which are used for determining and predicting the date of giving birth with the electronic system according to the invention, particularly by using the first and the second sensor system 101, 102.

[0132] In FIG. 2 box 201 includes the detected parameters, i.e. the heart rate and a heart rate variability determined from the signals of the first sensor system 101 and the acceleration of the wearable device 1 as determined from the second sensor system 102.

[0133] As illustrated in FIG. 2, in step S1, the heart rate of the pregnant person wearing the wearable device 1 is measured using the wearable device 1. Specifically, in the state of the device 1 being worn, e.g. on the wrist, the processor 13 of the wearable device 1 reads or receives from the first sensor system 101 the current heart rate of the pregnant person. The processor 13 stores the heart rate (value) in the data storage 12 together with a time stamp, including the current time and date.

[0134] In (an optional) step S2, the heart rate variability of the pregnant person is measured using the wearable device 1. Specifically, in the state of the device 1 being worn, e.g. on the wrist, the processor 13 of the wearable device 1 reads or receives from the first sensor system 101 the current heart rate variability of the pregnant person. The processor 13 stores the heart rate variability (value) in the data storage 12 together with a time stamp, including the current time and date.

[0135] In step S3, the movement or acceleration, respectively, of the pregnant person is measured using the wearable device 1. Specifically, in the state of the device 1 being worn, e.g. on the wrist, the processor 13 of the wearable device 1 reads or receives from the second sensor system 102 the acceleration of the wearable device and thus the acceleration of the wrist of the pregnant person. The processor 13 stores the acceleration (value) in the data storage 12 together with a time stamp, including the current time and date. In some simplified embodiments, step S3 is omitted.

[0136] Preferably, the measurements of the heart rate, the heart rate variability, and the acceleration of the pregnant person are performed concurrently. The measurements of the first and the second sensor system 101, 102 are performed periodically, for example the first sensor system 101 uses the optical sensors to measure the heart rate and heart rate variability every couple of milliseconds. In an embodiment, the periodic measurements are limited to specific time intervals, e.g. during night time, when the pregnant person sleeps, such that the heart rate is measured during sleep phases only.

[0137] Depending on the embodiment and/or configuration, further processing of the detected heart rate, heart rate variability, and acceleration of the pregnant person is performed by the processor 13 of the wearable device 1 and/or by the processor(s) 30, 40 of the computer system 3 and/or the mobile communication device 4. In a case that involves processing by the processor(s) 30 of the computer system 3, the measured and time stamped values of the heart rate, heart rate variability, and acceleration are transmitted by the communication module 14 from the wearable device 1 via the network 2 to the computer system 3, as indicated by step S4 in FIG. 2, e.g. directly or via the mobile communication device 4 as a relay device. In a case that involves processing by the processor 40 of the mobile communication device 4, the measured and time stamped values of the heart rate, heart rate variability, and acceleration are transmitted by the communication module 14 from the wearable device 1 via the close range communication interface to the mobile communication device 4 where they are stored in the data storage system 41. In the computer system 3 and/or the mobile communication device 4, respectively, the received measurement values are stored securely assigned to the pregnant person, defined, for example, by a user identifier and/or a device identifier (for increased anonymity/privacy). Transmission of the time stamped measurements is performed periodically, for example; typically, the measurement data is transmitted less frequently than the measurements are taken, e.g. various time stamped measurement samples, taken at different times, are grouped and transmitted together by the wearable device 1 in a combined data transmission.

[0138] In step S5, the heart rate variability and the acceleration are used (by the processor 13 of the wearable device and/or by the processor(s) 30, 40 of the computer system 3 and/or the mobile communication device 4) to detect sleep phases with a resting pulse. Detecting sleep phases with resting pulse allows detecting the heart rate each night in the same state of activity of the pregnant person. The sleep phases are detected, for example, by combining the measurements of the heart rate variability and acceleration as described by Renevey et al. cited above. In a simplified embodiment, the sleep phase is determined without using the measured acceleration and the second sensor system at all, for example based on a user-defined sleep interval, e.g. between 3:00 am and 4:00 am.

[0139] In step S6, the processor 13 of the wearable device 1 and/or the processor(s) 30, 40 of the computer system 3 and/or the mobile communication device 4 detect changes of the heart rate, e.g. the resting pulse. In other words, the processor(s) 13, 30, 40 determine changes of the heart rate, i.e. changes in the duration of the interval between individual heart beats, respectively, that occur during the detected sleep phases with resting pulse. Specifically, the processor(s) 13, 30, 40 determine the points in time when the resting pulse rate in the third trimester of the pregnancy starts decreasing.

[0140] In a simplified embodiment, the wearable device 1 and/or the processor(s) 30, 40 of the computer system 3 and/or the mobile communication device 4 detect changes of the pulse during pregnancy, without a limitation to a detected sleep phase, but at a specific point in time, e.g. during the night, for example based on a user-defined sleep interval, e.g. between 3:00 am and 4:00 am.

[0141] As seen in FIG. 3, determination of the date of delivery can be calculated as the date of onset of a decrease in heart rate in the third trimester plus 5.5 weeks+/−0.5 weeks.

[0142] The date of childbirth CB is encircled for the different groups.

[0143] The heart rate parameter used in the analysis is the 10.sup.th percentile of the heart rate measurements of the full night per subject per night. Weekly averages are then calculated per subject and these are further normalized by subtracting the average of this parameter prior to conception, to account for differing base lines. Subjects have been sorted into delivery week groups and the average for each group and week is displayed. A total of 644 pregnancies were used for this analysis. 66 are in delivery week group “<37”, 193 in “37-38”, 339 in “39-40” and 46 in “>=41” as explained above.

[0144] As can been seen in all groups after conception the heart rate increases to a local maximum around week 5-6 followed by a short period of a decrease. Starting from week 10, the heart rates in all groups increase approximately until week 30 after conception. Depending on the date of childbirth a period 50 of decreasing heart rates indicated by the boxed region follows to the maximum heart rate around week 30.

[0145] Obviously it is possible to differentiate between the decrease around week 10 and 30, simply by providing an approximate date of conception.

[0146] The electronic system and method is configured such that the onset of said period is detected and a prediction of the date of childbirth becomes possible.

[0147] From FIG. 3 it can be seen that for example in the group of pregnant persons that gave birth before week 37 the onset of the period 50 of decreasing heart rate shows earlier and remains steep, as compared to for example the group of pregnant women that gave birth in week 39 to 40.

[0148] The onset of the period 50 can be determined detecting three to four heart rates (or filtered sets of heart rates) estimated over a week, that are consecutively decreasing. Such a pattern gives a clear indication of an imminent childbirth.

[0149] Alternatively, the detection of said onset can be for example also facilitated by means of a trained classifier, such as an artificial neural network that is provided with the weekly heart rates.

[0150] The method and the electronic system allow for providing the pregnant person with a date of childbirth. In one embodiment the predicted date of childbirth is combined with information about a confidence value that indicates an estimated probability associated with the predicted date of childbirth.

[0151] For example when the heart rate decreases two weeks in a row around week 30, a date of child birth can be determined. However, as can be seen for example for the groups giving birth before week 37 and between week 37 and 38 (and even for deliver after week 41), the onset of the period 50 of decreasing heart rates is very similar such that an accurate prediction requires more measurement points. Nonetheless, a probability (confidence information) for each possible week of delivery can be given such that the pregnant person is able to put the determined date of childbirth in perspective.

[0152] The electronic system and the method according to the invention allows for a novel, reliable and non-invasive way of predicting the date of childbirth.

REFERENCES

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