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Evolution of graphic analysis of labor
Evolution of graphic analysis of labor EMA:-.1UEL A . FRIEDMA;-';, M.D., MED.Sc.D . Boston, l\1.assachuseus
THE FORTUITOUS cOr-;JU:-;CTION of the professional pathways of a number of stimulating, clinically oriented academicians in an almost ideally fertile, thought-provoking environment conspired to give birth to the graphic concept of the analysis of labor progression just 25 years ago. At the College of Physicians and Surgeons of Columbia University in the midcentury, the Department of Obstetrics and Gynecology was nearing the zenith of its development under the inspired leadership of Dr. Howard C. Taylor, Jr. Clinical teaching in obstetric care was being supervised by Dr. D. Anthony D'Esopo in a manner characterized by conservatism tempered with inquiry and analysis. The heritage of the great Sloane Hospital for Women, only recently incorporated physically into the melting pot of the Columbia-Presbyterian Medical Center, still prevailed. In the presence of those whose promise was already recognized, including such incomparable clinical laboratorians as Drs. Albert A. Plentl and Donald Hutchinson (whose untimely deaths are still mourned), there was an atmosphere most conducive t.o the germination of novel concepts. And the "soil" was made especially fertile by the intensity of concern and uniformly high quality of nursing skills brought to bear under the strong influence of Lottie :v1orrison, who ran the obstetric nursing service with both insight and compassion. Perhaps the catalyst in this unique milieu was the person of Dr. Virginia Apgar, who at this time was in charge of the obstetric anesthesia service. She served to generate an excitement of curiosity in the best academic sense; no dogma was sacred in her critical incisive mind or safe from her probing inquiry. Her legendary energy was boundless and her enthusiasm infectious. In t.his setting, young and impressionable residents in training, such as I, were swept up in a whirlwind of both clinical and laboratory inyestigation. Unlike the situation that was to prevail later in the 1960's when the From the Department oj Obstetrics and Gynecology, Hon'ard Medical School, Beth IJrael Hospital. Reprint requests: Dr. Emanuel A. Friedman, Department oj Obstetric.1 and Gynecology, Beth lime I Hospital, Boston. Massachusettl 02215.
824
embarrassment of National Institutes of Health riches often served as the primary (if not sole) impetus and motivation for the pursuit of r esearch activities, the drive at that time had to be generated from within each individual so inclined. While investigational pursuits were expected and encouraged, they were deemed to be extracurricular in nature and something to be accomplished on an ad hoc basis, superimposed on the otherwise fairly full structured clinical educational program, without formal commitments of time. space , or fiscal allocations. These relative impediments notwithstanding, much important work was undertaken, leading to productive academic careers for many. Much of the thrust among clinical obstetric studies being conducted during this time centered about caudal anesthesia. The potentiality of this lechniqu(~ fired the imagination of proponents such as Dr. Apgar, who envisioned it as bordering 011 the elusive ideal heing sought for achieving pain relief ill lahor that was safe and simple and would not affect the felus or the course oflabor. With regard to this last aspect, only the barest beginnings had been made in objective monitoring of uterine contractility. Techniques were being actively developed. Only two years ea rlier Alvarez and Caldeyro-Barcia 1 had startled a disbelieving obstetric community with reports describing graphic recordings of intrauterine hydrostatic pressure and laler the use of intramyometrial microballoons for this purpose. These reports were instrumental in opening the entire held of physiologic experimentation in human pregnancy
©
19i8 Th" C. V. ~Io,b)" Co,
Vol lime 1'12 :\'umlx'r 7
diminished intensity and frequency of contractions. While this was obviously a meaningful observation, it did not really provide a measure of the over-all effect of the anesthesia on the course of labor, although it inferred inhibition. The only measures of clinical effect available then were data on the duration of labor (first and second stages and total duration, respectively), and the literature was replete with conflicting testimonial series attesting to the shorter, longer, or unaffected average lengths of labor with caudal anesthesia. Repeating this type of "experiment" was considered likely to be an ill-advised exercise in futility. Instead we searched for some other, more sensitive, objective means of studying labor and its progression. Others had traveled the same tortuous pathway before, and their monuments, like those of Ozymandias, lay scattered half buried in the sands of our literature. Reports by Calkins and colleagues 2'- 4 extended over the preceding two decades and presented a growing mass of objective data bearing on variations in the length of the stages of labor. Calkins was convinced that accurate observations of the resistance of the cervix and of the pelvic floor, together with determinations of the effectiveness of the uterine contractiolls, were necessary to solve the riddle relating to the extreme variations in the length of labor so commonly encountered in clinical practice. He felt that critical observations of the existing forces of labor and the counteracting resistance would enable him to predict the probable duration of labor, serving to reduce the high rate of operative interference. He urged that the consistency of the cervix, as well as the thickness of its wall and the length of its canal, be accurately determined and recorded. Calkins'3 work culminated in a report detailing the factors relevant to prediction of the length of the first stage. He showed that it was possible, on the basis of observations of intensity of contractions, degree of cervical effacement, softening of the cervix, and engagement of the fetal presenting part, to predict the approximate length of the normal first stage. Subsequently, a similar approach was developed for predicting second-stage duration by paying particular attention to the number of contractions it took to evolve the descent process. He emphasized the sequence of contractions rather than the elapsed time, until then considered almost exclusively. This revived a once-popular method, the Wehenzahlen (pain count) technique, first developed and popularized by Frey" in 1929. Frey felt that labor would not evolve without a predetermined given number of sufficiently strong contractions and that this number was more important than the time factor involved. His attempt at graphic representation consisted of half-
Evolution of graphic analysis of labor
825
hourly notations of the accumulated number, average duration, and character of the contractions, together with other information on cervical effacement and dilatation and the degree of engagement. Most nulliparous patients were found to require more than 300 contractions after rupture of the membranes and most multiparous patients more than 200. M It is apparent that this approach was the forerunner of more recent techniques, which summate number and intensity of contractions in a similar sequential but cOllsiderably more meaningful manner. Unfortunately, neither the Wehenzahlen technique nor that of Calkins provided means for accurate evaluation of the labor in progress, both being directed to over-all summations of factors bearing on total duration, leaving much to be desired with reg-
826 Friedman
Koller and Abt 10. II described a graphic representation of the course of labor, in 1948, that was said to facilitate the practical control of the entire process and permit scientific study. Their Partograrnm consisted of a coordinate record with zero time representing the point at which the membranes ruptured. Cervical dilatation was represented on an irregular scale, the divisiems of which were unequal. Several steps in cervical dilatation and the delivery process, each representing a phase, were used. These included the diameters of a 1 to 2 franc coin, a 5 franc coin, a small palm, a palm, complete dilatation, delivery of the bahy, and delivery of the placenta. Superimposing curves aligned at zero time , the time of rupture of the membranes, Koller demonstrated that dispersion of the patterns before and after this event is different. that is, the curve is less steeply inclined prior to amniotomy alld more rapid following it. Although presenting no data at all on patients with intact memhranes, he concluded that the effect seen was the result of amnioLOmy. which influences the duration of the total period of dilatation and the duration of the period of expulsion. Zimmer 17 presented studies, in 1950 with the use of a Wegzeit-Diagramm (course-time graph); he also utilized rupture of the membranes as the central theme. His curves were essentially hyperbolic in pattern. their sigmoid characteristics having been ignored. Although a marked change in slope was recognized to occur normally beyond 3 to 4 cm .. no transition was accepted and pure linearity was insisted upon. The inAuence of dystocia. inertia, or other conditions as they related to changes in the curve was not recognized. Variations in the pattern, both quantitative and qualitative, were not described. The device was used only in its academic role and strictly on a retrospective basis. Moreover , it had the major fault of centering the curve at the time of rupture of membranes. This ddiciency, together with the nonlinear, irregular dilatation scale and the assumption that linear change existed throughout. was reflected in the rough picture of the course of labor it was able to provide. Furthermore, it offered almost no ongoing means for evaluating a labor in progress. As stated, the prime objective of most of these early investigations was the effect of amniotomy on labor. Despite the intensive effort that had been expended, essentially ignored was the matter of objective study for purposes of defining the complex phenomenon of labor, establishing norms for its course with which comparisons might be made more accurately and more profitably , and determining meaningful limits of normal. In retrospect, these serious shortcomings tended to nullify a good deal of the value of these foregoing studies. l\ievertheless. they did play an important role,
"::'1 f· · ~'·~': ·
Am.
J. .)'".',
(. ~ 1' 11 ' (.
serving to form the foundation upon " hi ' I :.il apili. analytic techniques in current use were i ';lIi , Insofar as purely clinical hKtors were '. H, ' ·c nled. til<: subject appeared to have heen extensin'h ,JIll: .,'xtJ,.,.. :tively investjgated. and the likelihood tk,' :1;C lIsdul additional information would be f()rthc()1I1 ~ 1l"'; ".,.:s ,1_' 1 V remote. Despite this Opt'lIl\ expressed pC " S!) \l i sli]. [he need was too pressing to he ignored .mll : his 1;,11 \ (' disbeliever embarked on a pilot st.ud\" with tlw llbjel 1iH' ill mind of trying to detennill(' whether (a lldal ,,1l{, Sthesia, when transiently applied in t ht' ( uurse 0\ dll otherwise lIormal hlbor, could be showII to inHut'lJ(l' its progression. 1 chose at the outset merdy tll assess periodic levels ill each of the six characteristic Inanitestations of clinical labor that were assumed to advance steadily throughout labor. progressive change heing the hyword of every definition of labor till then--·'lIId still to date. These included intensity. frequency itnd duratioll of contractions. cervical effan'ment and dilatation. and descent of the fetal presenting part. Each was expressed in strictly clinical terIllS and plotted on square-ruled graph paper against tillle. From the \Try first case. it was apparent t hat progressive ccrvical dilatation was going to be of greatest significance to li S as an index of labor progression. and ITlllch excitement was generated among those willing to sec . AI this late date it seems inconceivable that. such an obviollsly simplistic and utilitarian technique had not been developed intuitively and put to wide use tnany years earlier. Morever, the resistance it encountered in achieving acceptance and routine adoption in clinical practice cannot now be fully comprehended. Anecdotally , it might he of interest to note here that the first "acid test." of this technique was a brici comparison of two groups of gravid wOIllcn. one subjected to the ostensible stimulation of
Volume 132
Evolution of graphic analYSis of labor
:-.lumber 7
servations of uterine contractility, on one hand, were too sensitive and did not reflect true over-all progressive change. Data on total duration, on the other hand, were too insensitive to allow detection of any transient effects of the anesthesia. A sim pie, objective, reproducible, clinically available [001 was thought to be necessary for this purpose. It soon became obvious that evaluation of progress in labor, previously synonymous with a nebulous degree of change, must be made available to . us in terms of specific rate of change. This was conceived as a possible solution to our dilemma. We proceeded without prior knowledge of the foregoing work in this area. In retrospect, this was perhaps fortunate since it was thereby possible to avoid the ensnarements of these prior approaches. The rest is history. A method was devised whereby the rate of change in
827
cervical dilatation could be related in a reasonably precise manner to elapsed time. It was during the long night of June 10, 1953, that the too-frequent periodic examinations I made on the first patient studied (B. 1\., Unit No. 120448) immediately revealed the now familiar characteristic sigmoid curve of normal cervical dilatation. Since that time, extensive study has revealed that the rate of change, within the limits of acceptable error, is specific for each patient and undergoes predictable alterations during the course of normallabor. 6 This technique has introduced a new dimension to us and has proved to be a useful clinical tool. Stemming from this early seed of discovery and invention wrought by necessity, many tangential explorations have been possible, and as a consequence much has been learned about labor.
REFERENCES I . Alvarez, A., and Caldeyro-Barcia, R.: La actividad contractil uterina en el estado gravida puerperal, Proc. Primer Congreso Vruguayo de Ginecologia, March, 23-27 1949, Montevideo. 2. Calkins, 1. A.: lbe length of labor. III. The first stage: Labor pains and consistency of cervix, AM. ]. OBSTET. GYNECOL. 27: 349, 1934. 3. Calkins, 1. A.: On predicting the length of labor. I. First stage, AM.]. OBSTET. GYNECOL. 42: 802,1941. 4. Calkins, I.. A., Irvine,]. H ., and Horsley, G. W.: Variation in the length of labor, AM.]. OBSTET. GY:-IECOL. 19: 294, 1930. 5. Frey, E.: Die Bedeutung der WehentafeI fur die Physiologie und Pathologie der Geburt beim vorzeitigen Blasensprung, Schweiz. Med. Wochenschr. 59: 613, 1929. 6. Friedman, E. A.: Graphic analysis of labor, AM.]. OBSTET. GYNECOL. 68: 1568, 1954. 7. Friedman, E. A., and Sachtleben, M. R.: Amniotomy and the course of labor, Obstet. Gyneco!. 22: 755, 1963. 8. Geisendorf, W.: Le nombre des contractions dans raccouchement dirige, Gyneco!. Obstet. 35: 355, 1937. 9. Hallet. R. 1.: The conduct of labor and results with con-
10. II. 12. 13. 14. 15. 16. 17.
tinuous caudal anesthesia, AM. ]. OBSTET. CYSECOL. 66: 54, 1953. Koller, T.: Versuch einer graphischen Darstellung des Geburtsverlaufes, Cyneco!. Invest. 126: 227, 1948. Koller, T., and Abt, K.: Das verticale Partogramm als zusatzliche Kontrolle des Geburtsverlaufes, Gyneco!. Invest. 130: 419, 1950. Kroenig, W.: Der Ersatz der inneren Vntersuchung Kreissender durch die Cntersuchung per rectum, Zenlralb!. Gynaekol. 18: 235, 1894. Langredcr, W.: Geburtshilfliche Messungen , Bibl. Gynaeco!. 20: 9. 1959. Liepmann, W.: Die Grossenbestimmung des ausseren Muttermundes in der Geburt, ein Vorschlag fur Vnterricht und Praxis, Zentralb!. Gynaeko!. 45: 1289, 1921. Ries, D.: Cber die innere Cntersuchung Kreissender durch den Mastdarm, Zentralb!. Gynaeko!. 18: 404, 1894. Wolf, W.: Der unzeitige Blasensprunge, Stuttgart. 1946, Wissenschaftliche Verlag, p. 103. Zimmer, K.: Die Muttermundseriiffnung bei den Schadellagen im Wegzeit-DiagTamm, Arch. Gynaekol. 179: 35.1951.
THE FORTUITOUS cOr-;JU:-;CTION of the professional pathways of a number of stimulating, clinically oriented academicians in an almost ideally fertile, thought-provoking environment conspired to give birth to the graphic concept of the analysis of labor progression just 25 years ago. At the College of Physicians and Surgeons of Columbia University in the midcentury, the Department of Obstetrics and Gynecology was nearing the zenith of its development under the inspired leadership of Dr. Howard C. Taylor, Jr. Clinical teaching in obstetric care was being supervised by Dr. D. Anthony D'Esopo in a manner characterized by conservatism tempered with inquiry and analysis. The heritage of the great Sloane Hospital for Women, only recently incorporated physically into the melting pot of the Columbia-Presbyterian Medical Center, still prevailed. In the presence of those whose promise was already recognized, including such incomparable clinical laboratorians as Drs. Albert A. Plentl and Donald Hutchinson (whose untimely deaths are still mourned), there was an atmosphere most conducive t.o the germination of novel concepts. And the "soil" was made especially fertile by the intensity of concern and uniformly high quality of nursing skills brought to bear under the strong influence of Lottie :v1orrison, who ran the obstetric nursing service with both insight and compassion. Perhaps the catalyst in this unique milieu was the person of Dr. Virginia Apgar, who at this time was in charge of the obstetric anesthesia service. She served to generate an excitement of curiosity in the best academic sense; no dogma was sacred in her critical incisive mind or safe from her probing inquiry. Her legendary energy was boundless and her enthusiasm infectious. In t.his setting, young and impressionable residents in training, such as I, were swept up in a whirlwind of both clinical and laboratory inyestigation. Unlike the situation that was to prevail later in the 1960's when the From the Department oj Obstetrics and Gynecology, Hon'ard Medical School, Beth IJrael Hospital. Reprint requests: Dr. Emanuel A. Friedman, Department oj Obstetric.1 and Gynecology, Beth lime I Hospital, Boston. Massachusettl 02215.
824
embarrassment of National Institutes of Health riches often served as the primary (if not sole) impetus and motivation for the pursuit of r esearch activities, the drive at that time had to be generated from within each individual so inclined. While investigational pursuits were expected and encouraged, they were deemed to be extracurricular in nature and something to be accomplished on an ad hoc basis, superimposed on the otherwise fairly full structured clinical educational program, without formal commitments of time. space , or fiscal allocations. These relative impediments notwithstanding, much important work was undertaken, leading to productive academic careers for many. Much of the thrust among clinical obstetric studies being conducted during this time centered about caudal anesthesia. The potentiality of this lechniqu(~ fired the imagination of proponents such as Dr. Apgar, who envisioned it as bordering 011 the elusive ideal heing sought for achieving pain relief ill lahor that was safe and simple and would not affect the felus or the course oflabor. With regard to this last aspect, only the barest beginnings had been made in objective monitoring of uterine contractility. Techniques were being actively developed. Only two years ea rlier Alvarez and Caldeyro-Barcia 1 had startled a disbelieving obstetric community with reports describing graphic recordings of intrauterine hydrostatic pressure and laler the use of intramyometrial microballoons for this purpose. These reports were instrumental in opening the entire held of physiologic experimentation in human pregnancy
©
19i8 Th" C. V. ~Io,b)" Co,
Vol lime 1'12 :\'umlx'r 7
diminished intensity and frequency of contractions. While this was obviously a meaningful observation, it did not really provide a measure of the over-all effect of the anesthesia on the course of labor, although it inferred inhibition. The only measures of clinical effect available then were data on the duration of labor (first and second stages and total duration, respectively), and the literature was replete with conflicting testimonial series attesting to the shorter, longer, or unaffected average lengths of labor with caudal anesthesia. Repeating this type of "experiment" was considered likely to be an ill-advised exercise in futility. Instead we searched for some other, more sensitive, objective means of studying labor and its progression. Others had traveled the same tortuous pathway before, and their monuments, like those of Ozymandias, lay scattered half buried in the sands of our literature. Reports by Calkins and colleagues 2'- 4 extended over the preceding two decades and presented a growing mass of objective data bearing on variations in the length of the stages of labor. Calkins was convinced that accurate observations of the resistance of the cervix and of the pelvic floor, together with determinations of the effectiveness of the uterine contractiolls, were necessary to solve the riddle relating to the extreme variations in the length of labor so commonly encountered in clinical practice. He felt that critical observations of the existing forces of labor and the counteracting resistance would enable him to predict the probable duration of labor, serving to reduce the high rate of operative interference. He urged that the consistency of the cervix, as well as the thickness of its wall and the length of its canal, be accurately determined and recorded. Calkins'3 work culminated in a report detailing the factors relevant to prediction of the length of the first stage. He showed that it was possible, on the basis of observations of intensity of contractions, degree of cervical effacement, softening of the cervix, and engagement of the fetal presenting part, to predict the approximate length of the normal first stage. Subsequently, a similar approach was developed for predicting second-stage duration by paying particular attention to the number of contractions it took to evolve the descent process. He emphasized the sequence of contractions rather than the elapsed time, until then considered almost exclusively. This revived a once-popular method, the Wehenzahlen (pain count) technique, first developed and popularized by Frey" in 1929. Frey felt that labor would not evolve without a predetermined given number of sufficiently strong contractions and that this number was more important than the time factor involved. His attempt at graphic representation consisted of half-
Evolution of graphic analysis of labor
825
hourly notations of the accumulated number, average duration, and character of the contractions, together with other information on cervical effacement and dilatation and the degree of engagement. Most nulliparous patients were found to require more than 300 contractions after rupture of the membranes and most multiparous patients more than 200. M It is apparent that this approach was the forerunner of more recent techniques, which summate number and intensity of contractions in a similar sequential but cOllsiderably more meaningful manner. Unfortunately, neither the Wehenzahlen technique nor that of Calkins provided means for accurate evaluation of the labor in progress, both being directed to over-all summations of factors bearing on total duration, leaving much to be desired with reg-
826 Friedman
Koller and Abt 10. II described a graphic representation of the course of labor, in 1948, that was said to facilitate the practical control of the entire process and permit scientific study. Their Partograrnm consisted of a coordinate record with zero time representing the point at which the membranes ruptured. Cervical dilatation was represented on an irregular scale, the divisiems of which were unequal. Several steps in cervical dilatation and the delivery process, each representing a phase, were used. These included the diameters of a 1 to 2 franc coin, a 5 franc coin, a small palm, a palm, complete dilatation, delivery of the bahy, and delivery of the placenta. Superimposing curves aligned at zero time , the time of rupture of the membranes, Koller demonstrated that dispersion of the patterns before and after this event is different. that is, the curve is less steeply inclined prior to amniotomy alld more rapid following it. Although presenting no data at all on patients with intact memhranes, he concluded that the effect seen was the result of amnioLOmy. which influences the duration of the total period of dilatation and the duration of the period of expulsion. Zimmer 17 presented studies, in 1950 with the use of a Wegzeit-Diagramm (course-time graph); he also utilized rupture of the membranes as the central theme. His curves were essentially hyperbolic in pattern. their sigmoid characteristics having been ignored. Although a marked change in slope was recognized to occur normally beyond 3 to 4 cm .. no transition was accepted and pure linearity was insisted upon. The inAuence of dystocia. inertia, or other conditions as they related to changes in the curve was not recognized. Variations in the pattern, both quantitative and qualitative, were not described. The device was used only in its academic role and strictly on a retrospective basis. Moreover , it had the major fault of centering the curve at the time of rupture of membranes. This ddiciency, together with the nonlinear, irregular dilatation scale and the assumption that linear change existed throughout. was reflected in the rough picture of the course of labor it was able to provide. Furthermore, it offered almost no ongoing means for evaluating a labor in progress. As stated, the prime objective of most of these early investigations was the effect of amniotomy on labor. Despite the intensive effort that had been expended, essentially ignored was the matter of objective study for purposes of defining the complex phenomenon of labor, establishing norms for its course with which comparisons might be made more accurately and more profitably , and determining meaningful limits of normal. In retrospect, these serious shortcomings tended to nullify a good deal of the value of these foregoing studies. l\ievertheless. they did play an important role,
"::'1 f· · ~'·~': ·
Am.
J. .)'".',
(. ~ 1' 11 ' (.
serving to form the foundation upon " hi ' I :.il apili. analytic techniques in current use were i ';lIi , Insofar as purely clinical hKtors were '. H, ' ·c nled. til<: subject appeared to have heen extensin'h ,JIll: .,'xtJ,.,.. :tively investjgated. and the likelihood tk,' :1;C lIsdul additional information would be f()rthc()1I1 ~ 1l"'; ".,.:s ,1_' 1 V remote. Despite this Opt'lIl\ expressed pC " S!) \l i sli]. [he need was too pressing to he ignored .mll : his 1;,11 \ (' disbeliever embarked on a pilot st.ud\" with tlw llbjel 1iH' ill mind of trying to detennill(' whether (a lldal ,,1l{, Sthesia, when transiently applied in t ht' ( uurse 0\ dll otherwise lIormal hlbor, could be showII to inHut'lJ(l' its progression. 1 chose at the outset merdy tll assess periodic levels ill each of the six characteristic Inanitestations of clinical labor that were assumed to advance steadily throughout labor. progressive change heing the hyword of every definition of labor till then--·'lIId still to date. These included intensity. frequency itnd duratioll of contractions. cervical effan'ment and dilatation. and descent of the fetal presenting part. Each was expressed in strictly clinical terIllS and plotted on square-ruled graph paper against tillle. From the \Try first case. it was apparent t hat progressive ccrvical dilatation was going to be of greatest significance to li S as an index of labor progression. and ITlllch excitement was generated among those willing to sec . AI this late date it seems inconceivable that. such an obviollsly simplistic and utilitarian technique had not been developed intuitively and put to wide use tnany years earlier. Morever, the resistance it encountered in achieving acceptance and routine adoption in clinical practice cannot now be fully comprehended. Anecdotally , it might he of interest to note here that the first "acid test." of this technique was a brici comparison of two groups of gravid wOIllcn. one subjected to the ostensible stimulation of
Volume 132
Evolution of graphic analYSis of labor
:-.lumber 7
servations of uterine contractility, on one hand, were too sensitive and did not reflect true over-all progressive change. Data on total duration, on the other hand, were too insensitive to allow detection of any transient effects of the anesthesia. A sim pie, objective, reproducible, clinically available [001 was thought to be necessary for this purpose. It soon became obvious that evaluation of progress in labor, previously synonymous with a nebulous degree of change, must be made available to . us in terms of specific rate of change. This was conceived as a possible solution to our dilemma. We proceeded without prior knowledge of the foregoing work in this area. In retrospect, this was perhaps fortunate since it was thereby possible to avoid the ensnarements of these prior approaches. The rest is history. A method was devised whereby the rate of change in
827
cervical dilatation could be related in a reasonably precise manner to elapsed time. It was during the long night of June 10, 1953, that the too-frequent periodic examinations I made on the first patient studied (B. 1\., Unit No. 120448) immediately revealed the now familiar characteristic sigmoid curve of normal cervical dilatation. Since that time, extensive study has revealed that the rate of change, within the limits of acceptable error, is specific for each patient and undergoes predictable alterations during the course of normallabor. 6 This technique has introduced a new dimension to us and has proved to be a useful clinical tool. Stemming from this early seed of discovery and invention wrought by necessity, many tangential explorations have been possible, and as a consequence much has been learned about labor.
REFERENCES I . Alvarez, A., and Caldeyro-Barcia, R.: La actividad contractil uterina en el estado gravida puerperal, Proc. Primer Congreso Vruguayo de Ginecologia, March, 23-27 1949, Montevideo. 2. Calkins, 1. A.: lbe length of labor. III. The first stage: Labor pains and consistency of cervix, AM. ]. OBSTET. GYNECOL. 27: 349, 1934. 3. Calkins, 1. A.: On predicting the length of labor. I. First stage, AM.]. OBSTET. GYNECOL. 42: 802,1941. 4. Calkins, I.. A., Irvine,]. H ., and Horsley, G. W.: Variation in the length of labor, AM.]. OBSTET. GY:-IECOL. 19: 294, 1930. 5. Frey, E.: Die Bedeutung der WehentafeI fur die Physiologie und Pathologie der Geburt beim vorzeitigen Blasensprung, Schweiz. Med. Wochenschr. 59: 613, 1929. 6. Friedman, E. A.: Graphic analysis of labor, AM.]. OBSTET. GYNECOL. 68: 1568, 1954. 7. Friedman, E. A., and Sachtleben, M. R.: Amniotomy and the course of labor, Obstet. Gyneco!. 22: 755, 1963. 8. Geisendorf, W.: Le nombre des contractions dans raccouchement dirige, Gyneco!. Obstet. 35: 355, 1937. 9. Hallet. R. 1.: The conduct of labor and results with con-
10. II. 12. 13. 14. 15. 16. 17.
tinuous caudal anesthesia, AM. ]. OBSTET. CYSECOL. 66: 54, 1953. Koller, T.: Versuch einer graphischen Darstellung des Geburtsverlaufes, Cyneco!. Invest. 126: 227, 1948. Koller, T., and Abt, K.: Das verticale Partogramm als zusatzliche Kontrolle des Geburtsverlaufes, Gyneco!. Invest. 130: 419, 1950. Kroenig, W.: Der Ersatz der inneren Vntersuchung Kreissender durch die Cntersuchung per rectum, Zenlralb!. Gynaekol. 18: 235, 1894. Langredcr, W.: Geburtshilfliche Messungen , Bibl. Gynaeco!. 20: 9. 1959. Liepmann, W.: Die Grossenbestimmung des ausseren Muttermundes in der Geburt, ein Vorschlag fur Vnterricht und Praxis, Zentralb!. Gynaeko!. 45: 1289, 1921. Ries, D.: Cber die innere Cntersuchung Kreissender durch den Mastdarm, Zentralb!. Gynaeko!. 18: 404, 1894. Wolf, W.: Der unzeitige Blasensprunge, Stuttgart. 1946, Wissenschaftliche Verlag, p. 103. Zimmer, K.: Die Muttermundseriiffnung bei den Schadellagen im Wegzeit-DiagTamm, Arch. Gynaekol. 179: 35.1951.