JPS5855775B2 - Labor progress monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects the active phase of the first stage of labor by comparing the electromyogram signal detected during labor with a reference value.
The present invention relates to a labor progress monitoring device that generates a labor warning signal for transition to phase 2 or abnormal labor in the active phase.

Figure 1 shows the labor progression curve, showing the latent phase (1ate
The process progresses in an S-shape from the first stage of labor, which consists of an active phase of rapid dogfighting of the cervix (nt phase) and rapid dog fighting of the cervix, to the second stage of labor, in which delivery of the baby takes place.

In this curve, the time of the latent phase is not only long but also varies widely depending on the parturient woman, whereas the active phase is usually only a few hours and has less variation, making it easier to predict the time of delivery of the baby. Become.

The onset of this active phase can be detected by internal examination, but it is troublesome to perform this repeatedly and is also uncomfortable for the pregnant woman.

For this reason, a device called a cervix dilatation meter has been desired for some time, but one that can be used for practical purposes has not yet been completed.

Recently, labor monitoring devices based on continuous patterns of labor contractions and fetal heart rate have become indispensable during childbirth, and although they can detect abnormalities in the mother or fetus in advance, they cannot detect the onset of the active phase. I couldn't do it.

For example, if we look at the pattern of labor pains, there is a tendency for the level to increase slightly from the latent phase to the active phase, but no significant difference is seen even after the transition to the active phase.

In view of this, an object of the present invention is to provide a labor progress monitoring device that can continuously monitor the active phase of labor without performing an internal examination.

This is based on the physiologically important finding that, as shown in Figure 2, the level of electromyogram signals detected from the abdominal wall increases markedly as the active phase progresses, and this is based on the physiologically important finding that the level of electromyogram signals detected from the abdominal wall increases markedly as the active phase progresses. It is solved by comparing the detected electromyogram signal with a predetermined reference level.

Figure 2 illustrates changes in the electromyogram signal and labor signal detected by an electromyogram electrode attached to the abdominal wall with respect to the progress of the active phase, where a is the electromyogram signal that is simply amplified, and b C shows a half-wave envelope electromyogram signal obtained by rectifying and integrating the electromyogram signal, and C shows a labor signal.

If we pay particular attention to the electromyogram signal in the same figure, we can see that as the activity phase progresses, electromyogram signals of very low level begin to occur irregularly when the labor signal C occurs, and from the display start point in Figure 2, 4
After 0 minutes, when the labor signal C occurs, an electromyogram signal starts to be generated regularly, and its level also starts to rise rapidly.

The level continues to rise between 56 minutes and 80 minutes from the display start point.

After 80 minutes, it continues to rise and passes through the second stage of labor.
The baby is delivered at 0 minutes.

Therefore, the present invention utilizes electromyogram signals for monitoring childbirth, and will be explained below based on the illustrated embodiment.

FIG. 3 is a block diagram showing a circuit configuration of a labor progress monitoring device capable of warning that labor has shifted to the active phase as a first embodiment of the present invention.

In the same figure, 2 and 2' are electromyogram electrodes attached to the abdominal wall 1 of the pregnant woman, 3 is a labor transducer also attached to the abdominal wall 1, and 4 is detected by the electromyogram electrodes 2 and 2'. An AC amplifier that amplifies the electromyogram signal, and 5 a rectifier-integrator circuit that forms a half-wave envelope of the amplified electromyogram signal in preparation for addition (described later) to improve the S/N of the electromyogram signal. It is.

6 is a DC amplifier that amplifies the DC component from the labor transducer 3 and the labor signal superimposed thereon, which can be considered to be almost a DC component, and 7 is a labor gate generation circuit that generates a gate corresponding to labor based on the amplified labor signal. It is.

Reference numeral 8 denotes a moving addition circuit, which chronologically converts the electromyogram signal supplied from the rectifying and integrating circuit 5 while the gate is being supplied from the labor gate generation circuit 7 for a certain period of time, for example, 10 minutes during the progress of labor. Add to that.

Therefore, the moving adder circuit 8 constantly outputs an addition signal for a time that goes back a certain period of time during the progress of labor, and at this time, due to the gate action, noise signals during intermittent labor are not added.

The moving addition circuit 8 can also be configured to count the gates during contractions and add the electromyogram signals corresponding to a constant number of contractions, for example, 5 times, instead of adding up a certain amount of time.

Reference numeral 9 denotes a reference level setting circuit that generates a reference level with which the added electromyogram signals are compared.

This reference level is set based on known data regarding the electromyogram signal at the beginning of the active phase, and in order to increase the accuracy of the alarm, it is necessary to obtain an electromyogram signal whenever a labor signal occurs after entering the active phase. It is preferable to set the level of the active phase region such that

Furthermore, if the reference level can be finely adjusted according to the intrauterine pressures of several pregnant women, the accuracy of the alarm can be improved.

10 compares the added electromyogram signal with a reference level;
This is a comparator that generates an alarm signal to notify the transition to the active phase when the electromyogram signal exceeds a reference level.

In the labor progress alarm device having the circuit configuration described above, normally in the latent phase, no electromyogram signal is detected from the electromyogram electrodes 2 and 2', and only a labor signal is detected from the labor transducer 3. Only the labor gate is input, and the summed electromyogram signal is not output.

As the latent phase progresses further to near the starting point of the active phase, electromyogram signals are occasionally detected when gates occur during labor, and an added electromyogram signal begins to be supplied to the comparator 10.

When labor progresses further in the active phase and an electromyogram signal is always detected when gates occur during labor, the comparator 10 exceeds the reference level of the added electromyogram signal and issues an alarm to indicate the transition to the active phase. .

For example, if the reference level is set to the level obtained by adding the electromyogram signal at 44 minutes after the start of display in Fig. 2, then
For a pregnant woman with the electromyogram signal shown in FIG. 2, a warning about transition to the active phase is issued approximately 10 to 20 minutes after the transition to the active phase.

FIG. 4 shows a second embodiment of the present invention, in which circuit parts having the same reference numerals as in FIG. 3 have corresponding functions.

In this embodiment, the input to the moving adder circuit 8 is supplied from a divider circuit 11 which calculates the ratio of the rectified and integrated electromyogram signal to the labor signal including the DC component (electromyogram signal/labor signal).

The introduction of this divider circuit 11 enables more accurate warnings than in the first embodiment.

That is, since individual level fluctuations in the process of increasing the electromyogram signal level correspond to fluctuations in the labor signal level, the rising tendency of the electromyogram signal level can be standardized by determining the ratio to the labor pain signal level.

Similarly, variations in electromyogram signal levels between pregnant women are standardized, and errors in alarm timing between pregnant women are reduced.

In this embodiment as well, the reference level of the reference level setting circuit 9 may be set based on a predetermined ratio, or may be finely adjusted each time.

FIG. 5 shows a third embodiment of the invention.

In this case, the comparator 10 may follow the moving adder circuit 8 of FIG. 3 or 4, the reference level of which can be followed by a reference level setting circuit 12 which generates a reference level that can change over time.
Supplied from.

This reference level setting circuit normally generates a reference level for transition to the active phase, but once the comparator 10 issues an alarm signal for transition to the active phase as the added electromyogram signal level rises, the ramp waveform The circuit is started and the reference level increases over time.

The slope of this ramp waveform is set at the lower limit of the normal range of the rate of increase in the electromyogram signal level during the active phase, and can be adjusted depending on whether the woman is a primiparous woman or a multiparous woman.

With this circuit configuration, after the transition to the active phase, the increase in the electromyogram signal level over time may be interrupted or decrease due to abnormal labor such as prolonged labor, and the level of the added electromyogram signal may exceed the ramp waveform level. When the cycle goes down, the alarm signal from the comparator 10 that has been generated after the notification of the transition to the active phase disappears, and at this time, the abnormal delivery alarm circuit 13 is started and an alarm signal for abnormal delivery is generated.

Note that the ramp waveform circuit can be started manually based on the results of the internal examination, and the change level can be set according to the degree of progress of the active phase at that time.

Incidentally, the alarm signal in each of the above embodiments can be made to emit an alarm sound via a buzzer or a pager.

It is also possible to perform telemetry by transmitting an electromyogram signal or a labor signal together with the electromyogram signal.

An internal tocodynamometer can also be used instead of an external tocodynamometer.

As is clear from the above explanation, by using the electrocardiogram signal that is detected during the active phase and increases in level as it progresses, the present invention can reliably and automatically determine that labor has entered the active phase without the need for a pelvic examination. will be able to notify the public.

Furthermore, by monitoring changes in the level of the electromyogram signal, it is possible to automatically detect abnormal labor during the active phase.

[Brief explanation of the drawing]

Fig. 1 shows a standard labor progression curve, Fig. 2 shows an example of an electromyogram signal and a labor signal detected near the starting point of active phase, and Figs. 3, 4, and 5 show the present invention. FIG. 2 is a block diagram showing a circuit configuration of an embodiment of the present invention. 1...abdominal wall, 2...electromyogram electrode, 3.
... Labor transducer, 5... Rectifier/integrator circuit, 7... Labor gate generation circuit, 8.
...Moving adder circuit, 10...Comparator, 1
1...Division circuit, 12...Reference level generation circuit, 13...Abnormal delivery alarm circuit.

Claims (1)

[Claims] 1. A rectifying and integrating circuit for an electromyogram signal detected by an electromyogram electrode attached to the abdominal wall of a pregnant woman, and a labor gate that generates a gate corresponding to a labor signal detected by a labor transducer attached to the pregnant woman. a generation circuit, a moving adder circuit that constantly adds back in time the electromyogram signals from the rectifying and integrating circuit while the gate is being generated by the gate generator circuit, and an output signal of the moving adder circuit and a reference. A device for monitoring the progress of labor, comprising a comparator for comparing the level with the level.