JPS63145639A - Delivery monitor apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a labor monitoring device, and more particularly to a labor monitoring device having a function of automatically recording fetal movements and fetal heart rate. .

(Prior Art) Fetal movements have long been attracting attention as an important indicator of the viability of a fetus.

Conventionally, a common method for detecting this type of fetal movement has been to press a remote marker switch when a pregnant woman senses fetal movement, and record the marker using a recorder built into a birth monitoring device.

(Problems to be Solved by the Invention) However, this method is a subjective method, cannot record all fetal movements, and requires consideration of individual differences, which has drawbacks in measuring fetal movements.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a birth monitoring device that automatically records fetal movements.

(Means for Solving the Problems) The present invention provides, as a means for achieving the above object, a transmitting means for making ultrasonic waves incident from the body surface of a pregnant and nursing mother, and a transmitting means for transmitting ultrasonic waves that are incident on the body of the expectant and nursing mother and reflected within the body of the expectant and nursing mother. a receiving means for receiving the ultrasonic waves; and a receiving means for processing the electrical signals received by the receiving means to generate signals from the ultrasonic waves reflected from non-stationary parts of the pregnant woman's body with a frequency shift caused by the Doppler effect, that is, Doppler signals. a fetal signal included in the Doppler signal obtained by the processing means, that is, a fetal movement signal generated by fetal movement, and a fetal heartbeat that is generated in synchronization with the fetal heart movement and whose level is smaller than the fetal heartbeat signal. and means for separating the fetal heartbeat signal from a composite signal containing the fetal movement signal and the fetal heartbeat signal as main components, using a level difference between the fetal movement signal and the fetal heartbeat signal.

(Structure) The present invention will be explained in detail below with reference to embodiments shown in the drawings. 1 is an ultrasonic transducer in an ultrasonic transducer;
The transducer is fixed on the abdominal wall of the pregnant woman with tape or a belt.

Reference numeral 2 denotes an ultrasound transmitting circuit, which transmits an electrical signal at the ultrasound frequency to be transmitted, and when the ultrasound is transmitted from above the abdominal wall into the pregnant woman's body via the ultrasound transducer 1, a part of this ultrasound is transmitted. It reflects from internal tissues and their interfaces and returns to the body surface.

3 is an ultrasonic receiving circuit which amplifies the signal of the reflected wave received by the ultrasonic transducer 1 and converts the received wave and the transmitted wave whose frequency has shifted due to the Doppler effect when the interface inside the body moves. The amplified signal is sent to a detection circuit 4 that outputs a signal having a difference frequency component (hereinafter referred to as a Doppler signal).

The frequency of the Doppler signal changes depending on the motion speed of the moving body, the ultrasonic frequency F, the ultrasonic speed C, and the incident angle e,
In the above case, the frequency of the obtained Doppler signal is Doppler frequency Fd=FX(2VX COSθ)/C. That is, a Doppler signal with a frequency corresponding to the motion speed is obtained from the detection circuit 4.

The amplitude of this Doppler signal is proportional to the strength of the ultrasound reflected wave, but since fetal movements, especially rotational movements of the trunk and head, are accompanied by large reflected waves, the Doppler signal is caused by Doppler waves reflected from the fetal heart. The amplitude is about 100 times (40db) compared to the signal. Therefore, when the output of the detection circuit 4 is directly rectified and detected by the fetal movement signal detection circuit 5, a signal that can be used as a fetal movement signal is obtained. This fetal movement signal is amplified by the fetal movement signal amplification circuit 6 and recorded by the recorder 8. In addition, in order to exclude the influence of reflected waves other than small-amplitude fetal movements, the fetal movement reference voltage setting circuit 9 creates a reference voltage 7, and the voltage comparison circuit 7 compares the fetal movement signal voltage with the reference voltage to determine the amplitude level. It is also possible to determine a signal that may be a low reflected signal and reject the output, thereby recording only the fetal movement signal.

The output from this voltage comparator circuit 7 becomes a spike-like waveform that occurs with fetal movement, and the recorder 8 can record this spike-like waveform as it is, but the presence or absence of the spike-like waveform can be determined by checking the state of rlJ rOJ. It can also be converted and recorded as a fetal movement marker signal. The recording of this marker signal has the same expression as that recorded when a pregnant woman senses fetal movement and presses a remote marker switch, so it can be handled in the same way as conventional fetal movement recording.

In the above, the means for detecting the Doppler signal with the detection circuit 4 and extracting the fetal movement signal or fetal movement marker signal from the signal has been explained. Explain the means to obtain it.

The Doppler signal output from the detection circuit 4 includes a component that is reflected back from the fetal heart, and thereby the fetal heart rate can be measured.

The amplitude of the reflected waves from the fetal heart is about 1/100 of that of fetal movement, so it becomes impossible to measure when there is fetal movement.
Using this level difference, signals below a certain level that do not correspond to fetal movements can be separated as fetal heartbeat signals, and the heartbeat signal filter 11 extracts them as signal components due to fetal heartbeats.

This fetal heartbeat signal is detected by a heartbeat signal detection circuit 12, then distinguished and measured as a heartbeat by a heart rate counting circuit 13, and recorded as a heart rate by a recorder 8.

On the other hand, the labor signal detected by the strain gauge 14 in the labor transducer on the abdominal wall is transmitted to the labor signal amplification circuit 1.
5 and recorded by a 3-channel recorder 8.

These records of heart rate, fetal movements, and labor pains can be recorded simultaneously on paper using a three-channel recorder, and can be recorded using a common time axis, which has the advantage of allowing the relationship between heart rate, fetal movements, and labor pains to be observed.

When using fetal movement marker signals, they are converted to rlj rOJ logical signals, so a 2-channel recorder is used instead of a 3-channel recorder to record labor signals.
It is also possible to insert a mark only when the value is ``fetal movement'', that is, ``1''.

This mark may be a stick or an arrow. That is, although the embodiment is explained using a three-channel recorder in the drawings, it goes without saying that the present invention is not limited to the type of recorder.

In addition, in this embodiment, the use of level difference as a means to separate heartbeat signals has been described, but this technique can also be used to remove noise, and outputs below a certain level, including noise, are removed by a rejecter, and the It is also possible to treat only the above outputs as valid signals. Various other modifications may be considered, but none of these modifications depart from the spirit of the present invention.

(Effects) As described above, the childbirth monitoring device according to the present invention includes a transmitting means for transmitting ultrasonic waves from the body surface of the expectant and nursing mother, and a receiver for receiving the ultrasonic waves incident by the transmitting means and reflected within the body of the expectant and nursing mother. - a processing means for processing the electric signal received by the receiving means to obtain a Doppler signal, that is, an ultrasound signal reflected from a non-stationary part of the pregnant woman's body with a frequency shift caused by the Doppler effect; The main components are a fetal signal included in the Doppler signal obtained by the processing means, that is, a fetal movement signal generated by the movement of the fetus and a fetal heartbeat signal that is generated in synchronization with the fetal heart movement and whose level is smaller than the fetal heartbeat signal. and a means for separating the fetal heartbeat signal from a composite signal including the fetal movement signal and the fetal heartbeat signal by using the level difference between the fetal movement signal and the fetal heartbeat signal. In addition, it has various effects such as being able to objectively and easily record heart rate, fetal movements, and labor pains simultaneously, and confirming the relationship between them.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of a childbirth monitoring device according to the present invention. 1... Ultrasonic transducer, 2... Ultrasonic transmitter circuit, 3...
Ultrasonic receiving circuit, 4. Detection circuit, 5. Fetal movement signal detection circuit, 6. Fetal movement signal amplification circuit, 7. Voltage comparison circuit, 8. 3-channel recorder, 9. Fetal movement reference voltage setting circuit. , 10... heartbeat signal filter,
11.. Heartbeat signal detection circuit, 12.. Heart rate measurement circuit, 13.. Strain gauge, 14.. Labor pain signal amplification circuit.

Claims (1)

[Claims] a transmitting means for injecting ultrasound waves from the body surface of the expectant and nursing mother; a receiving means for receiving the ultrasound waves incident by the transmitting means and reflected within the body of the expectant and nursing mother; A processing means for obtaining a Doppler signal, that is, an ultrasound signal reflected from a non-stationary part of the body by causing a frequency shift due to the Doppler effect, and a fetal signal, that is, a fetal signal included in the Doppler signal obtained by the processing means, Using the level difference between the fetal movement signal and the fetal heartbeat signal from a composite signal that includes as main components the fetal movement signal and a fetal heartbeat signal that is generated in synchronization with the fetal heart movement and has a lower level than the fetal heartbeat signal. and means for separating the fetal heartbeat signal.