JPH0349457B2 - - Google Patents

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 a marker using a recorder built into a birth monitoring device.

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

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

(Means for Solving the Problems) As a means for achieving the above object, the present invention provides a transmitting means for injecting ultrasonic waves from the body surface of a pregnant and nursing mother, and a transmitting means for transmitting ultrasonic waves into the body of the pregnant and nursing mother. Receiving means for receiving the reflected ultrasound; and a signal of the ultrasound reflected from a non-stationary part of the pregnant woman's body by processing the electrical signal to produce a frequency shift due to the Doppler effect. That is, a processing means for obtaining a Doppler signal, 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 movement signal generated in synchronization with the movement of the fetal heart, which is compared to the fetal signal. and means for separating the fetal heartbeat signal from a composite signal containing as a main component a fetal heartbeat signal of a small level by using a level difference between the fetal movement signal and the fetal heartbeat signal. It is a monitoring device.

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

2 is an ultrasound transmitting circuit that transmits an electrical signal at the ultrasound frequency to be transmitted, and when the ultrasound is transmitted from the abdominal wall into the pregnant woman's body via the ultrasound transducer 1, some of this ultrasound is transmitted inside the body. It is reflected from the 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 when the interface inside the body moves, the received wave and the transmitted wave whose frequency is shifted due to the Doppler effect. The amplified signal is sent to a detection circuit 4 which outputs a signal (hereinafter referred to as a Doppler signal) having a frequency component different from that of the Doppler signal.

The frequency of the Doppler signal is the motion velocity V of the moving body,
It varies depending on the ultrasonic frequency F, the ultrasonic velocity C, and the incident angle Θ, and in the above case, the frequency of the obtained Doppler signal is Doppler frequency Fd=F×(2V×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. It has an amplitude about 100 times (40 db) compared to the signal, so if the output of the detection circuit 4 is directly rectified and detected by the fetal movement vibration detection circuit 5, a signal that can be used as a fetal movement signal is obtained. This fetal movement signal is amplified by a fetal movement signal amplification circuit 6 and recorded by a 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, and the voltage comparison circuit 7 compares the fetal movement signal voltage with the reference voltage. It is also possible to determine signals that may be other reflected signals and reject the output, thereby recording only fetal movement signals.

The output from this voltage comparator circuit 7 becomes a spike-like waveform that occurs with fetal movement.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 as "1" or "0". ”
It is also possible to convert the state into a fetal movement marker signal and record it 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 reflected back from the fetal heart, and thereby the fetal heart rate can be measured. The amplitude of the reflected wave from the fetal heart is about 1/100 of that of fetal movement, so it becomes unmeasurable when there is fetal movement, but this level difference can be used to detect signals below a certain level that do not correspond to fetal movement. can be separated as a fetal heartbeat signal, and a heartbeat vibration filter 11 extracts it as a signal component due to the fetal heartbeat.

This fetal heartbeat signal is transmitted to the heartbeat signal detection circuit 1.
2, the heart rate counting circuit 13 distinguishes and measures the heartbeat as a heartbeat, and the recorder 8 records the heartbeat.

On the other hand, the labor signal detected by the strain gauge 14 in the labor transducer on the abdominal wall is amplified by the labor signal amplification circuit 15 and recorded by the 3-channel recorder 8 as well.

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 a fetal movement marker signal, it is converted into a logic signal of "1" or "0", so instead of a 3-channel recorder, a 2-channel recorder is used to record labor signals to indicate "fetal movement", that is, " It is also possible to insert a mark only when the value is 1.
This mark may be a stick or an arrow. That is, although the embodiment is illustrated using a three-channel recorder, it goes without saying that the present invention is not limited to the type of recorder.

(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 receiving the ultrasonic waves that are input by the transmitting means and reflected within the body of the expectant and nursing mother. a receiving means; 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 body of a pregnant woman by causing a frequency shift due to the Doppler effect; , a fetal signal contained in the Doppler signal obtained by the processing means, that is, a fetal heartbeat signal generated in synchronization with the fetal movement caused by the movement of the fetus and the fetal heart movement and whose level is smaller than that of the fetal heartbeat signal. and a means for separating the fetal heartbeat signal from a composite signal containing as a main component by using the level difference between the fetal movement signal and the fetal heartbeat signal. It has various advantages such as being able to obtain simultaneous records of heart rate, fetal movements, and labor pains continuously, objectively, and easily, and confirming the relationship between them.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1. A transmitting means for injecting ultrasonic waves from the body surface of the expectant and nursing mother, a receiving means for receiving the ultrasonic waves incident by the transmitting means and reflected within the body of the expectant and nursing mother, and an electric signal received by the receiving means. A processing means for processing and obtaining a Doppler signal, that is, an ultrasound signal reflected from a non-stationary part of a pregnant woman's body by causing a frequency shift due to the Doppler effect, and a fetal signal included in the Doppler signal obtained by the processing means. That is, the fetal movement signal and the fetal heartbeat are obtained from a composite signal that includes as main components a fetal movement signal generated by fetal movement 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. A delivery monitoring device comprising means for separating the fetal heartbeat signal using a level difference between the fetal heartbeat signal and the fetal heartbeat signal.