Abstract:
The present invention is directed to a system and method for monitoring the dilatation of the uterine cervix during labor and deliver. The system has a gauge and a monitoring unit. In one embodiment the gauge includes features for convenient attachment to the gloved fingertips of the clinician performing a routine digital probing of the cervix. The monitoring unit includes a sensor to automatically read the measurement of the gauge and a processor to process, record and display the sensor data. This system may be valuable for the assessment of the progress of labor and the early detection of delivery complications.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This Application claims the benefit of U.S. Provisional Application No. 60/777,248, filed Feb. 26, 2006, entitled Measurement Aid for Digital Cervix Examination, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a system and method for monitoring the dilatation of the uterine cervix during labor and delivery, in particular, a system and method utilizing a gauge that adheres to the gloved fingertips of a clinician for measuring the diameter of the cervical opening. 
       BACKGROUND OF THE INVENTION 
       [0003]    The diameter of the opening of the uterine cervix (or cervical diameter, used interchangeably herein) increases during the final stages of pregnancy to facilitate the birth process and enable the delivery of the fetus. The cervical diameter is considered an important obstetrical indicator and therefore, its accurate measurement may be valuable for the assessment of the progress of labor and the early detection of delivery complications. The measurement of the cervical diameter may affect the decision of whether to wait for a normal delivery, to administer a labor inducing drugs, or to perform a C-section delivery. 
         [0004]    Current clinical practice for measuring the cervical diameter is performed manually by inserting a gloved hand into the vagina and then using the middle and index fingers to probe the diameter of the cervix. The fingertips are used to palpate and locate the cervical Os and the fingers are then spread apart such that their tips are in contact with the opposite edges of the cervical opening. The degree of fingers spread may be used to assess the distance between the fingertips, which corresponds to the diameter of the cervix opening. 
         [0005]    This digital probing method is approximate and its accuracy is primarily dependent on the experience of the examiner in estimating the cervical diameter using fingers. This type of measurement is not repeatable even by the same examiner. The accuracy may be further degraded by interobserver variability if different clinicians examine the patient during the course of labor. One examiner cannot reliably communicate that degree of dilation to another examiner without some objective scale. Such inconsistent measurements of the cervix diameter may hinder the early detection of dysfunctional labor and delivery complications. 
         [0006]    There have been many attempts to develop devices for the accurate and user-independent measurement of the cervical diameter. However, these devices have failed to gain wide clinical acceptance due to several limitations, including the complexity of use, inaccuracy of measurements, tissue trauma caused by the devices or their components, costly sterilization between uses, and/or patient discomfort. 
         [0007]    Consequently, the digital probing method continues to be a favored method of measuring the cervical diameter. Therefore, there is a need to improve the accuracy of the digital probing method, reduce its interobserver variability, and enable a semi-automated recording of its measurements for the calculation of the cervical dilatation rate and the generation of a partogram. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention discloses a system and method for measuring the dilatation of the uterine cervix (or cervix, used interchangeably herein) during labor and delivery utilizing the routine digital probing method. 
         [0009]    The system is comprised of an attachable gauge and a monitoring unit. The gauge may include an indicator to display its extension and a means to adhere to the glove worn by the clinician during digital probing of the cervix. The indicator of the gauge may be visually readable to the clinician and/or machine readable by the monitoring unit. 
         [0010]    The application and utilization of the disclosed gauge may not require any additional effort, training or skills beyond that required for routine digital probing of the cervix. The gauge may be attached directly to the glove covering the two probing fingers of the clinician performing the cervix examination. 
         [0011]    In one embodiment, the indicator of the gauge may be a string that is configured in a zigzag or sawtooth pattern which changes appearance depending on the extension of the gauge. In another embodiment, the string may be arranged in a star-shaped pattern which also changes appearance depending on the extension of the gauge. 
         [0012]    The monitoring unit may include a sensor (e.g. a CCD or a barcode reader) to read the gauge indicator and acquire its measurement. The monitoring unit may also include a processor to calculate the dilatation rate and construct partogram from a series of consecutively measured cervical diameters. The monitoring unit may also include a display screen to display the cervical diameter, the dilatation rate, and the partogram. Furthermore, the monitoring unit may be used to setoff an alert to remind to the clinician to digitally probing of the cervix. 
         [0013]    In one method, the gauge may be attached to gloved probing fingers of the clinician, the probing fingers inserted into the vagina and spread apart to touch the rim of the cervical opening, the probing fingers withdrawn from the vagina, and the clinician reading the extension indicator of the gauge to determine the cervical diameter. In another method, a monitoring unit may be used to automatically read the indicator of the gauge and record its measurement to determine the cervical diameter and estimate the dilatation rate of the cervix from sequential measurements of the cervical diameter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows an embodiment of a gauge attached to gloved fingertips that are positioned to measure cervical diameter in accordance with the present invention. 
           [0015]      FIG. 2A  shows a top view of the gauge of  FIG. 1 . 
           [0016]      FIG. 2B  shows a side view of the gauge of  FIG. 1 . 
           [0017]      FIG. 3A  shows a gauge indicator reading a 3-cm cervical diameter. 
           [0018]      FIG. 3B  shows a gauge indicator reading a 5-cm cervical diameter. 
           [0019]      FIG. 3C  shows a gauge indicator reading a 8-cm cervical diameter. 
           [0020]      FIG. 4  shows another embodiment of the gauge. 
           [0021]      FIG. 5A  shows another embodiment of the gauge indicator with a star pattern. 
           [0022]      FIG. 5B  shows another embodiment of the gauge indicator with a fan pattern. 
           [0023]      FIG. 5C  shows another embodiment of the gauge indicator with a sinusoidal pattern. 
           [0024]      FIG. 5D  shows another embodiment of the gauge indicator with a coil pattern. 
           [0025]      FIG. 5E  shows another embodiment of the gauge indicator with an uneven sinusoidal pattern. 
           [0026]      FIG. 5F  shows a reflectance signal generated by optically scanning the uneven sinusoidal pattern of  FIG. 5E . 
           [0027]      FIG. 6  shows an embodiment of a monitoring unit in accordance with the present invention. 
           [0028]      FIG. 7  shows an embodiment of a display screen of a monitoring unit in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The cervix monitoring system is comprised of a gauge and a monitoring unit. The gauge may be manually used to measure the cervical diameter using the routine digital probing method. The monitoring unit may be used to automatically read the measurement of the gauge, record consecutive cervical diameter measurements, calculate the cervical dilatation rate, and display a partogram. 
         [0030]    A preferred embodiment of the disposable gauge  100  is shown in  FIG. 1  and  FIG. 2 . The gauge  100  may be composed of an anchor patch  102  and an indicator patch  104  that are interconnected with a measurement string  106 . 
         [0031]    The patches  102  and  104  are preferably thin and flexible and may be made of a soft material such as, for example, polyethylene, nylon, or silicone. The patches  102  and  104  may include an embedded fiber mesh (not shown) for structural reinforcement and to provide strong attachment points to the endings  150  and  152  of the string  106 . The patches  102  and  104  may have a typical diameter of about 1.5-cm while the string  106  may have a typical length of about 10-cm. The patches  102  and  104  may have a back surface  103  and  105  covered with an adhesive material  107  to enable their attachment to the material of the examination glove as described below. 
         [0032]    The adhesive material  107  may be of any kind that would allow a fast and a firm attachment of the patches  102  and  104  to the material of the examination glove. The adhesive  107  may be a pressure sensitive adhesive (PSA). 
         [0033]    The patch  102  may provide an anchor point  154  for the ending  150  of the string  106 . The indicator patch  104  may provide an anchor point  156  for the ending  152  of the string  106  but it may also include an additional portion of the string  106  packed in a zigzag or sawtooth pattern  122  between an optically transparent window  124  and a reflective background sheet  126 . 
         [0034]    The string may be arranged in the zigzag pattern  122  and stabilized in that form using a thin layer of a transparent pressure sensitive adhesive (not shown) placed between the transparent window  124  and a reflective background sheet  126 . The pressure sensitive adhesive (not shown) stabilizes the string  106  to maintain its zigzag pattern  122  without preventing the string  106  from being pulled out of the zigzag pattern  122  when the anchor patch  102  is moved away from the indicator patch  104 . 
         [0035]    The string  106  may be selected of a color that is highly contrasting with the color of the reflective background sheet  126 . For example, the color of the string  106  may be matte black, while the color of the reflective background sheet  126  may be bright white. 
         [0036]    The design and dimensions of the zigzag pattern  122  may be configured such that pulling out the string  106  from the indicator patch  104  may cause the sequential disappearance of the corners  128  of the zigzag pattern  122 . Each zigzag corner  128  may have an adjacent number  130  imprinted on the transparent window  124  or the reflective background sheet  126 . The largest numeral from the set  130  which does not have a zigzag corner  128  pointing to it represents the distance between the fingertips or the diameter  116  as illustrated by the example shown in  FIG. 3 . 
         [0037]    The gage  100  in  FIG. 3A  shows that the zigzag corner pointing to number  3  is missing which indicates that the distance  160  between the fingertips is about 3-cm. The gage  100  in  FIG. 3B  shows that all the zigzag corners pointing to all numbers up to 5 are missing which indicates that the distance  160  between the fingertips is about 5-cm. The gage  100  in  FIG. 3C  shows that all the zigzag corners pointing to all numbers up to 8 is missing which indicates that the distance  160  between the fingertips is about 8-cm. 
         [0038]    In a typical application, the user may wear an examination glove and press the anterior fingertip  108  of the middle finger  109  and the anterior fingertip  110  of the index finger  111  against the adhesive-covered back surface  103  of the patches  102  and the back surface  105  of the patch  104 , respectively. The patches  102  and  104  become attached to the anterior (or palmer) fingertips  108  and  110  of the fingers  109  and  111  of the gloved examiner hand  112 , respectively as shown in  FIG. 2 . 
         [0039]    The gloved fingers  109  and  111  may be inserted into the vagina  114  and spread opened until their tips  108  and  110  contact (or palpate) the lips (or rim) of the cervix  115  to measure the diameter  116  of the cervix opening  118 . The spreading action of the fingers  109  and  111  moves the patches  102  and  104  away from each other thereby pulling the string  106  out of the indicator patch  104 , which indicates the length of the pulled-out string as described below. The length of the pulled-out string corresponds to the distance between the fingertips  108  and  112  or equivalently the diameter  116  of the cervical opening  118 . 
         [0040]    Alternative to the numbers  130 , other representing alphanumeric symbols, color-coded spots, drawings, or measurement tick marks may be used. 
         [0041]    An alternative embodiment of the disposable gauge is shown in  FIG. 4 . The gauge  200  may have an anchor patch  202  and an indicator patch  204  that are initially connected together by a perforated line of separation  232 . The patches  202  and  204  may separate along the line of separation  232  only upon an intentional forcible opening of the fingers  109  and  111 . The initial force needed to separate anchor patch  202  from the indicator patch  204  may be adjusted by the shape and number of the perforations along the separation line  232 . This configuration may safeguard against unintentional opening of the fingers  109  and  111  prior to their proper positioning on the lips (or rim) of the cervix  115 . 
         [0042]    Alternative gauge embodiments may utilize geometrical patterns other than the zigzag pattern  122  such as, for example, the star pattern  522  shown in  FIG. 5A , the fan pattern  533  shown in  FIG. 5B , the sinusoidal pattern  544  shown in  FIG. 5C , and the coil pattern  555  shown in  FIG. 5D . The string  106  arranged in the uneven sinusoidal pattern  546  shown in  FIG. 5E  may have unequal separation distances  160  between its turns. These unequal distances between the turns of the sting  106  may produce electrical pulses of unequal timing  162  as shown in  FIG. 5F  when scanned by an optical reflectance sensor such as a barcode reader. The distances  160  may be configured to generate a timing  162  that is representative of the distance between the fingertips or the diameter  116 . 
         [0043]    The monitor  600  shown in  FIG. 6  may include an automatic gauge dispenser  602 , a gauge reader  604 , a display screen  606 , a measurement reminder light  608 , and a processor (not shown). 
         [0044]    The automatic gauge dispenser  602  may utilize a bilayer roll of non-stick tape (not shown) with the gauges  100  sandwiched in-between the two layers of the tape. The tape may be automatically advanced and its layers separated to offer the user one gauge at a time. The gauge  100  may be offered with its adhesive covered surfaces  103  and  105  facing upwards. 
         [0045]    The gauge reader  604  may be used to automatically read the measurement of the gauge  100 . The machine reader may utilize barcode reading technology; fingerprint reading technology, or optical imaging with image recognition techniques. The reading technology or the image analysis method will depend on the type of the geometrical pattern used in the indicator patch  104  of the gauge  100 . The gauge reader  604  transmits its reading to the processor which processes the diameter measurement with the time of the reading and compares it to previous diameter-time measurements to calculate the current dilatation rate and generate a partogram. The partogram is a graphical display of the cervical dilation versus time and may be used for the assessment of labor. The processor may display the information on the display screen  606 . A detailed view of the display screen is shown in  FIG. 7 . 
         [0046]    The processor may also trigger a reminder light  608  to alert the attending clinician to take a measurement of the cervical diameter. The light  608  may be turned on at a preselected time interval following the last reading to attract attention of the attending clinician that a new measurement is due to be taken. The reminder alert may be preferably of the silent visual type such as the reminder light  608 . However, reminder alert may be also of the audio type. The alert may be also an electronic signal transmitted to the local nursing station of the Labor and delivery ward.