The present disclosure relates generally to electrocardiography (ECG) and more specifically, to a sensor device for obtaining vital signs of a foetus.
BACKGROUND
Generally, electrocardiography (ECG) is a method to measure and record electrical potential detected from various parts of the body, especially heart. Over the years, several techniques have been developed to monitor the fetal status during pregnancy and are widely used in the medical field. These methods are necessary to detect possible abnormalities. Early detection of fetal morbidity can have a profound influence on the fetal outcome. The detection and monitoring of fetal heart activity, Uterine contraction, uterine EMG, maternal ECG, maternal heart rate, and the fetal movement are particularly useful in assessing the well-being of the foetus. Further, Vital signs, such as fetal heart rate and beat-to-beat rate, fetal movement and variability are altered by the sympathetic and parasympathetic nervous system, and thus provide an excellent indication of the well-being of the baby.
Conventionally, there are several methods commonly used today in non-invasive fetal monitoring, including acoustic methods, ultrasonic methods, and electrocardiography (ECG) methods. Acoustic methods involve obtaining fetal acoustics, including heart sounds. This includes using a fetoscope, a stethoscope, or phonographic instruments employing acoustic transducers. However, acoustic fetal monitors are generally difficult to administer, particularly for self-administration, require training, and generally provide limited diagnostic data. Furthermore, ultrasonic methods use reflected acoustic energy in the ultrasonic range to localize and visualize various fetal structures, including heart valves. However, ultrasonic monitoring requires training and the results lack electrophysiologic information. It also requires proper alignment, and thus

can be a challenge for self-administration when considering the movement of the fetus in the uterus. Ultrasonic equipment is expensive and consumes a large amount of power, and thus is not suitable for long-term battery-operated applications. For the above reasons, ultrasound monitoring has not been widely employed in ambulatory applications, particularly at home settings.
ECG monitoring is particularly useful in detecting and constantly monitoring a health status of a foetus. Conventionally, the ECG systems having a number of electrodes attached to a number of wires to a display unit is configured to be attached to a pregnant woman to obtain electrical signals corresponding to the foetus. However, these methods are complex, expensive and highly inconvenient as it requires high precision to record and monitor the signals received from conventional ECG equipments. Furthermore, the conventional ECG equipments cannot be readily used by pregnant women for continuously monitoring the status of the foetus.
Therefore, in light of the foregoing discussion, there exists a need to overcome various problems associated with conventional electrocardiography methods to obtain vital signs of the foetus.
SUMMARY
The present disclosure seeks to provide a sensor device for obtaining vital signs of a foetus.
According to an aspect, an embodiment of the present disclosure provides
a sensor device for obtaining vital signs of a foetus, the sensor device
comprising:
- a front portion placed in contact with a surface of an abdominal region
of a pregnant woman;

- a rear portion arranged to face away from the surface of the abdominal
region of the pregnant woman;
- a first electrode, a second electrode, a third electrode and fourth
electrode arranged on the front portion at predetermined positions to
receive surface potentials corresponding to vital signs of the foetus,
wherein:
- the first electrode and the third electrode are placed on a lateral midline of the abdominal region of the pregnant woman, and wherein the first electrode and the third electrode are equidistant from a navel of the pregnant woman along the lateral midline; and
- the second electrode and the fourth electrode are placed on a longitudinal midline of the abdominal region, wherein the longitudinal midline is perpendicular to the lateral midline, and wherein the second electrode and the fourth electrode are equidistant from the navel along the longitudinal midline;
- a ratio of a distance of the first electrode and/or the third
electrode from the navel and a distance of the second electrode
and/or the fourth electrode from the navel is in a range of 0.25 to
0.50.
Optionally, the first electrode is placed at 5% of half an abdominal girth from the navel, along the lateral midline on a left side of the navel.
Optionally, the third electrode is placed at 5% of half the abdominal girth from the navel, along the lateral midline on a right side of the navel.
Optionally, the second electrode is placed at 16.7% of half a symphysis fundal height from the navel, along the longitudinal midline towards a top side of the navel.
Optionally, the fourth electrode is placed at 16.7% of half a symphysis fundal height from the navel, along the longitudinal midline towards a bottom side of the navel.

Optionally, the sensor device further comprises a fifth electrode configured to capture a reference surface potential corresponding to vital signs of the foetus, wherein the fifth electrode is arranged on the front portion and below the fourth electrode, wherein the fifth electrode is in contact with a bony structure and wherein a distance of the fifth electrode from a pubic symphysis is in a range of 18 to 20 millimetres.
Optionally, each of the first electrode, second electrode, third electrode, fourth electrode and fifth electrode is detachably coupled with the front portion.
Optionally, the rear portion comprises a number of grooves for fitting a wire assembly from each of the first electrode, second electrode, third electrode, fourth electrode and fifth electrode to a common electrical connection point.
Optionally, the sensor device further comprises an annular ring protruding from the front portion and surrounding each of the first electrode, second electrode, third electrode, fourth electrode and the fifth electrode, wherein the annular ring facilitates a contact between each of the first electrode, second electrode, third electrode, fourth electrode and fifth electrode with the abdominal region of the pregnant woman.
Optionally, the sensor device further comprises a slit in the front portion and the rear portion to enable attachment of the sensor device to different sizes of abdominal regions.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
DESCRIPTION OF THE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1 is a schematic diagram of perspective view of front portion of sensor device, in accordance with an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of perspective view of rear portion of sensor device, in accordance with an embodiment of the present disclosure;
FIG. 3 is a schematic illustration of exploded view of the sensor device as shown in FIG. 1 and FIG. 2, in accordance with an embodiment of the present disclosure; and
FIG. 4 is a schematic illustration of an arrangement of attachment of electrodes to the front portion of the sensor device of FIG. 1, in accordance with an embodiment of the present disclosure; and
FIG. 5 is a schematic illustration of arrangement of the electrodes on a surface of the abdominal region of the pregnant woman, in accordance with an embodiment of the present disclosure.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DESCRIPTION OF EMBODIMENTS
In overview, embodiments of the present disclosure are concerned with a sensor device for obtaining vital signs of a foetus.
According to an aspect, an embodiment of the present disclosure provides a sensor device for obtaining vital signs of a foetus, the sensor device comprising:
- a front portion placed in contact with a surface of an abdominal region of a pregnant woman;
- a rear portion arranged to face away from the surface of the abdominal region of the pregnant woman;
- a first electrode, a second electrode, a third electrode and fourth
electrode arranged on the front portion at predetermined positions to
receive surface potentials corresponding to vital signs of the foetus,
wherein:
- the first electrode and the third electrode are placed on a lateral midline of the abdominal region of the pregnant woman, and wherein the first electrode and the third electrode are equidistant from a navel of the pregnant woman along the lateral midline; and
- the second electrode and the fourth electrode are placed on a longitudinal midline of the abdominal region, wherein the longitudinal midline is perpendicular to the lateral midline, and

wherein the second electrode and the fourth electrode are
equidistant from the navel along the longitudinal midline;
- a ratio of a distance of the first electrode and/or the third
electrode from the navel and a distance of the second electrode
and/or the fourth electrode from the navel is in a range of 0.25 to
0.50.
Referring to FIG. 1, there is shown a schematic diagram of perspective view of front portion of the sensor device 100, in accordance with an embodiment of the present disclosure. The sensor device 100 obtains vital signs of the foetus. Throughout the present disclosure, the term "vital signs" refers to one or more biological parameters that indicate presence of life in a foetus. Furthermore, the vital signs indicate a well-being of the foetus and vascular system of the foetus. For example, the vital signs include but are not limited to, fetal heart rate and beat-to-beat heart rate. Notably, the sensor device 100 obtains and monitors the vital signs of the foetus. Optionally, the sensor device 100 comprises an external power source or battery to power the electrodes to receive electrical signals corresponding to vital signs of the foetus. Optionally, the sensor device 100 may also comprise a memory to store the received electrical signals corresponding to vital signs of the foetus. It will be appreciated that the sensor device 100 is advantageously configured for long-term wear applications exceeding one week and lasting up to several months. Furthermore, the sensor device 100 can be comfortably worn even during sleep and bathing.
As shown, the sensor device 100 comprises a front portion 102 placed in contact with a surface of an abdominal region of a pregnant woman. Notably, the front portion 102 of the sensor device 100 is to be placed with the surface of the abdominal region of the pregnant woman. The term "abdominal region" as used herein refers to the region of a stomach of the pregnant woman wherein the foetus is likely to be placed. Further,

the sensor device 100 comprises a rear portion arranged to face away from the surface of the abdominal region of the pregnant woman, which shall be discussed in greater detail in conjunction with FIG. 2. Optionally, the front portion 102 and the rear portion are attached to each other by an adhesive. Optionally, the front portion 102 and the rear portion are composed of a soft foamy material that is non-reactive to human skin. For example, the front portion 102 and the rear portion are composed of silicone-based gel or rubber materials.
The sensor device 100 comprises a first electrode 104, a second electrode 106, a third electrode 108 and fourth electrode 110 arranged on the front portion 102 at predetermined positions to receive surface potentials corresponding to vital signs of the foetus. Hereinafter, for the sake of simplicity the terms "first electrode", "second electrode", "third electrode", and "fourth electrode" may collectively be referred to as "electrodes". The front portion 102 comprises one or more recesses configured to accommodate the electrodes 104, 106, 108, 110 in the corresponding recesses. Notably, the shape and size of each of the one or more recesses in the front portion 102 is substantially same as the shape and size of the electrodes 104, 106, 108, 110 arranged in the front portion 102.
Notably, the electrodes 104, 106, 108, 110 are configured to receive surface potentials corresponding to vital signs of the foetus. In an example, the electrodes 104, 106, 108, 110 are metallic structures such as metallic discs that are configured to receive electrical signals from the biological activities of the foetus, including vascular activities. In particular, the electrodes 104, 106, 108, 110 are configured to receive electrical impulses from the surface of the abdominal region of the pregnant woman. It will be appreciated that the electrodes 104, 106, 108, 110 and functioning of such electrodes 104, 106, 108, 110 for

the purpose of electrocardiography in the field of medical sciences is well known in the art.
Optionally, the sensor device 100 further comprises a fifth electrode 112 arranged on the front portion 102 and below the fourth electrode 110. Optionally, the fifth electrode 112 is configured to capture a reference surface potential corresponding to vital signs of the foetus. Notably, the surface potential received from the fifth electrode 112 is a reference against which surface potential from the first electrode 104, the second electrode 106, the third electrode 108 and the fourth electrode 110 is received.
Optionally, the sensor device 100 further comprises an annular ring 114, 116, 118, 120, 122 protruding from the front portion 102 and surrounding each of the first electrode 104, second electrode 106, third electrode 108, fourth electrode 110 and the fifth electrode 112. Herein, the annular rings 114, 116, 118, 120, 122 facilitate a contact between each of the first electrode 104, second electrode 106, third electrode 108, fourth electrode 110 and fifth electrode 112 with the abdominal region of the pregnant woman. Notably, the sensor device 100 when placed on the abdominal region of the pregnant woman, the attachment of the sensor device 100 to the surface of the abdominal region is facilitated by the corresponding annular rings 114, 116, 118, 120, 122 surrounding each of the first electrode 104, second electrode 106, third electrode 108, the fourth electrode 110, the fifth electrode 112. Notably, each of the annular rings 114, 116, 118, 120, 122 has adhesive properties that facilitates the contact between each of the first electrode 104, second electrode 106, third electrode 108, fourth electrode 110 and fifth electrode 112 with skin of the pregnant woman, thereby facilitating easy and repeated use. It will be appreciated that the annular rings 114, 116, 118, 120, 122 are composed of pressure sensitive adhesives (PSAs) safe for use on human skin, and exhibit

relatively high moisture vapor and oxygen transmission, allowing the skin to breathe. In particular, each of the electrodes 104, 106, 108, 110, 112 when gently pressed against the surface of the abdominal region of the pregnant woman, each of the annular rings 114, 116, 118, 120, 122 adheres with the surface of the abdominal region, thereby facilitating the contact therebetween. Furthermore, the adhesion between each of the annular rings 114, 116, 118, 120, 122 and the surface of the abdominal region also ensures that the sensor device 100 is accurately placed at the predetermined positions on the surface of the abdominal region throughout a period of monitoring the vital signs of the foetus.
Referring to FIG. 2, there is shown a schematic diagram of perspective view of rear portion 200 of sensor device 100, in accordance with an embodiment of the present disclosure. As shown, the sensor device 100 comprises the rear portion 200 arranged to face away from the surface of the abdominal region of the pregnant woman. Optionally, the rear portion 200 comprises a number of grooves 202, 204, 206, 208, 210 for fitting a wire assembly from each of the first electrode 104, the second electrode 106, the third electrode 108, the fourth electrode 110 and the fifth electrode 112 to a common electrical connection point 212. Notably, each of the wires can be snuggly fitted into the corresponding grooves 202, 204, 206, 208, 210 and connected to the common electrical connection point 212.
For example, the groove 202 accommodates a wire to connect the first electrode 104 and the common electrical connection point 212, the groove 204 accommodates a wire to connect the second electrode 106 and the common electrical connection point 212, the groove 206 accommodates a wire to connect the third electrode 108 and the common electrical connection point 212, the groove 208 accommodates a wire to connect the fourth electrode 110 and the common electrical connection

point 212, and the groove 210 accommodates a wire to connect the fifth electrode 110 and the common electrical connection point 212.
Optionally, the common electrical connection point 212 can be utilized to connect the electrical output received from the surface of the abdominal region to a display device such as a computer or an oscilloscope to display the corresponding surface potentials as received from each of the electrodes 104, 106, 108, 110, 112. Optionally, a wireless module can be connected to the common electrical connection point 212 to receive the surface potentials and wirelessly transmit the electrical output received from the surface of the abdominal region to a display device such as a computer or an oscilloscope to display the corresponding surface potentials as received from each of the electrodes 104, 106, 108, 110, 112.
Optionally, the sensor device 100 further comprises a slit 214 in the front portion 102 (as shown in FIG. 1) and the rear portion 200 to enable attachment of the sensor device to different sizes of abdominal regions. As shown, the sensor device 100 also comprises a cut-out 216 in a middle of the sensor devicelOO. In an example, a portion of both the front portion 102 and the rear portion 200 is removed from a centre of the sensor device to obtain the cut-out 216. Notably, the slit 214 is an extension of the cut-out 216 to allow easy and comfortable attachment of the sensor device 100 to different sizes of abdominal regions. It will be appreciated that different pregnant women may have sizes of abdominal regions. Furthermore, a same pregnant woman may also have different sizes of abdominal regions at different stages of pregnancy. For this reason, there is provided the slit 214 in the front portion 102 and the rear portion 200 to enable attachment of the sensor device 100 to different sizes of abdominal regions. Notably, when the sensor device 100 is placed on the surface of the abdominal region of the pregnant

woman, the slit 214 may provide a comfortable attachment of the sensor device by expansion thereof.
Referring to FIG. 3, there is shown a schematic illustration of exploded view of the sensor device 100 as shown in FIG. 1 and FIG. 2, in accordance with an embodiment of the present disclosure. As shown, the sensor device 100 comprises the front portion 102 and the rear portion 200. Further, the sensor device 100 comprises electrodes 302 (such as the first electrode 104, the second electrode 106, the third electrode 108, the fourth electrode 110, and the fifth electrode 112 as shown in FIG. 1) arranged in between the front portion 102 and the rear portion 200. Further, the sensor device 100 comprises wires 304 connecting the corresponding electrodes 302 to the common electrical connection point 212.
Referring to FIG. 4, there is shown an arrangement 400 of attachment of electrodes to the front portion 102 of the sensor device 100 of FIG. 1, in accordance with an embodiment of the present disclosure. Herein, each of the first electrode 104, the second electrode 106, the third electrode 108, the fourth electrode 110, and the fifth electrode 112 is detachably coupled with the front portion 102. For illustration purposes only, there is shown the third electrode 108 detached from the front portion 102. Notably, each of the first electrode 104, the second electrode 106, the third electrode 108, the fourth electrode 110, and the fifth electrode 112 can be detached from the front portion 102, for example, by pulling the electrodes 104, 106, 108, 110 and 112 perpendicularly away from the front portion 102. It will be appreciated that such an arrangement 400 ensures that the electrodes 104, 106, 108, 110 and 112 are easily replaceable, by employing an easy mechanism of connection and disconnection of the electrodes 104, 106, 108, 110 and 112. Therefore, making the front portion 102 and the rear portion (not shown) of the sensor device 100 reusable by replacing electrodes 104, 106, 108,

110 and 112 that may become non-functional after a prolonged use. Furthermore, detachably coupled electrodes 104, 106, 108, 110 and 112 make the sensor device 100 inexpensive and reduces a wastage of resources by making the sensor device 100 reusable.
Referring to FIG. 5, there is shown a schematic illustration of arrangement 500 of the electrodes on a surface of the abdominal region 502 of the pregnant woman, in accordance with an embodiment of the present disclosure. As shown, the first electrode 104, the second electrode 106, the third electrode 108, and the fourth electrode 110 are placed at predetermined positions to receive surface potentials corresponding to vital signs of the foetus. Furthermore, the fifth electrode 504 (such as the fifth electrode 112 of FIG. 1) is arranged below the fourth electrode 110. It is to be understood that the precise placement of the electrodes 104, 106, 108, 110, 112 in the abdominal region 502 of the pregnant woman enables the sensor device (as shown in FIG. 1 and FIG. 2) to effectively receive the desired surface potential corresponding to vital signs of the foetus. Moreover, the precise placement of the electrodes 104, 106, 108, 110, 112 at the corresponding predetermined positions ensures reception of strongest electrical signals corresponding to vital signals of the foetus.
As shown, the first electrode 104 and the third electrode 108 are placed on a lateral midline 506 of the abdominal region 502 of the pregnant woman. Herein, the first electrode 102 and the third electrode 108 are equidistant from a navel 508 of the pregnant woman along the lateral midline 506. As shown, the second electrode 106 and the fourth electrode 110 are placed on a longitudinal midline 510 of the abdominal region 502, wherein the longitudinal midline 510 is perpendicular to the lateral midline 506. Herein, the second electrode 106 and the fourth electrode 110 are equidistant from the navel 508 along the longitudinal midline 510.

Optionally, a ratio of a distance of the first electrode 104 and/or the third electrode 108 from the navel 508 and a distance of the second electrode 106 and/or the fourth electrode 110 from the navel is in a range of 0.25 to 0.50. For example, the ratio of the distance of the first electrode 104 and/or the third electrode 108 from the navel 508 and the distance of the second electrode 106 and/or the fourth electrode 110 from the navel may vary from 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, 0.46, or 0.48 up to 0.28, 0.29, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, 0.46, 0.48 or 0.50.
Optionally, the first electrode 104 is placed at 5% of half an abdominal girth from the navel 508, along the lateral midline 506 on a left side of the navel 508. Optionally, the third electrode 108 is placed at 5% of half the abdominal girth from the navel 508, along the lateral midline 506 on a right side of the navel 508. Optionally, the second electrode 106 is placed at 16.7% of half a symphysis fundal height from the navel 508, along the longitudinal midline 510 towards a top side of the navel 508. Optionally, the fourth electrode 110 is placed at 16.7% of half a symphysis fundal height from the navel 508, along the longitudinal midline 510 towards a bottom side of the navel 508. Optionally, the fifth electrode 504 is in contact with a bony structure. Herein, a distance of the fifth electrode 504 from a pubic symphysis 512 is in a range of 18 to 20 millimetres. For example, the distance of the fifth electrode 504 from a pubic symphysis 512 may be 18, 18.50, 19, or 19.50 millimetres up to 18.50, 19, 19.50 or 20 millimetres.
Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or

elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

We claim:

1.A sensor device for obtaining vital signs of a foetus, the sensor device
comprising:
- a front portion placed in contact with a surface of an abdominal region of a pregnant woman;
- a rear portion arranged to face away from the surface of the abdominal region of the pregnant woman;
- a first electrode, a second electrode, a third electrode and fourth
electrode arranged on the front portion at predetermined positions to
receive surface potentials corresponding to vital signs of the foetus,
wherein:
- the first electrode and the third electrode are placed on a lateral midline of the abdominal region of the pregnant woman, and wherein the first electrode and the third electrode are equidistant from a navel of the pregnant woman along the lateral midline; and
- the second electrode and the fourth electrode are placed on a longitudinal midline of the abdominal region, wherein the longitudinal midline is perpendicular to the lateral midline, and wherein the second electrode and the fourth electrode are equidistant from the navel along the longitudinal midline;
- a ratio of a distance of the first electrode and/or the third
electrode from the navel and a distance of the second electrode
and/or the fourth electrode from the navel is in a range of 0.25 to
0.50.
2. A sensor device as claimed in claim 1, wherein the first electrode is
placed at 5% of half an abdominal girth from the navel, along the lateral
midline on a left side of the navel.

3. A sensor device as claimed in claim 1, wherein the third electrode is placed at 5% of half the abdominal girth from the navel, along the lateral midline on a right side of the navel.
4. A sensor device as claimed in claim 1, wherein the second electrode is placed at 16.7% of half a symphysis fundal height from the navel, along the longitudinal midline towards a top side of the navel.
5. A sensor device as claimed in claim 1, wherein the fourth electrode is placed at 16.7% of half a symphysis fundal height from the navel, along the longitudinal midline towards a bottom side of the navel.
6. A sensor device as claimed in claim 1, further comprising a fifth electrode configured to capture a reference surface potential corresponding to vital signs of the foetus, wherein the fifth electrode is arranged on the front portion and below the fourth electrode, wherein the fifth electrode is in contact with a bony structure and wherein a distance of the fifth electrode from a pubic symphysis is in a range of 18 to 20 millimetres.
7. A sensor device as claimed in claim 6, wherein each of the first electrode, second electrode, third electrode, fourth electrode and fifth electrode is detachably coupled with the front portion.

8. A sensor device as claimed in claim 6, wherein the rear portion comprises a number of grooves for fitting a wire assembly from each of the first electrode, second electrode, third electrode, fourth electrode and fifth electrode to a common electrical connection point.
9. A sensor device as claimed in claim 6, further comprising an annular ring protruding from the front portion and surrounding each of the first electrode, second electrode, third electrode, fourth electrode and the fifth electrode, wherein the annular ring facilitates a contact between each of

the first electrode, second electrode, third electrode, fourth electrode and fifth electrode with the abdominal region of the pregnant woman.
10. A sensor device as claimed in claim 1, further comprising a slit in the front portion and the rear portion to enable attachment of the sensor device to different sizes of abdominal regions.