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Uterine overaction and its nomenclature
Correspondence Uterine Overaction and Its Nomenclature To the Editor: I am addressing this letter to you because the various types of overaction of thn uterus are difficult to define accurately and different writers use the same name for dif· ferent clinical entities; this is especially the case when uterine rings are mentioned. In 1913 I read a paper at the Royal Society of Medicine entitled ''The Contraction Ring as a Cause of Dystocia.'' In it, scattered reports of cases were collected from the literature and I described a specimen which I had obtained by removing the unopened pregnant uterus from a patient in labor. In England, the condition is known as a contraction ring; in the United States, Rudolph and Ivy call it a constriction ring. I think the term contraction ring has the advantage that, in midwifery, contraction is followed by relaxation sooner or later. At present, the terminology used to describe the various types of uterine rings is in a chaotic state; Rudolph and Fieldsl state that the various current names are: ring of Bandl, contraction of the ring of Bandl, contraction ring dystocia of White, retraction ring dystocia of Pride, simply contraction or retraction ring, uterine contraction ring and constriction ring of Rudolph. Pierce Rucker2 states that I was the first to differentiate a contraction ring from a retraction ring. This is the reason why I am writing to you on the subject, as I do not seem to have made the differences clear; as an example, I need go no further than the same page of Pierce Rucker's paper where he quotes H. W. Johnson's contribution on "Delay in Labor Caused by Mild Degrees of Bandl's Ring." In my opinion, this is an impossibility as the retraction ring of Bandl could never cause delay in labor. In obstructed labor, the fetus acts as a splint which keeps the length of the uterus constant and, since each contraction in the second stage of labor is followed by slight retraction, it follows that in the course of hours the upper segment becomes retracted and thicker; since the fetus is keeping the length of the uterine cavity constant, the lower segment must become thinner. There is no other way for the upper segment to become thicker while the length of the uterus remains constant except by thinning of the lower segment. The importance of the fetus acting as a stretcher and maintaining the length of the cavity of the uterus is stressed, as it is an important part of the process of obstructed labor. It is interesting to speculate what would occur if the fetus were absent, as in the utterly improbable case of the uterus trying to expell a large hydatidiform mole through an occluded cervix. Seeing that the essential condition of the uterus of obstructen labor is one of retraction, it is usual to call it ''tonic retraction of the uterus,'' although, unfortunately, it is sometimes referred to as ''tonic contraction.'' This is a misnomer as, in midwifery, contraction suggests a subsequent relaxation which never occurs in the uterus of obstructed labor, so it is better to speak of either the uterus of obstructed labor or tonic retraction. Tonic retraction is a slow process taking six or more hours in the second stage to develop. Except in the rare cases of pathological obstruction of the cervix (e.g., a cervical fibroid), tonic retraction does not occur in the first stage of labor or when the membranes are intact; it is a late second-stage phenomenon and is caused by disproportion. The mother's general condition is bad, with raised pulse and temperature, the abdomen is very tender and, per vaginam, the presenting part has a big caput and is fixed. As the placental site is continuously retracted, the fetus dies from lack of oxygen and so the fetal heart is never heard during tonic retraction. The junction of the retracted, thickened upper segment with the thinned, tense, distended lower segment is the retraction ring or ring of Band!. The thickened upper segment takes 2 em. or more gradually to merge into the thinned lower segment, but there is
407
UO.URESPUN DEN CE
Am. j. Obot. a Gyno.. February, 194Q
rwt any projection on the peritoneal aspect and nothing that could be palpated. During a laparotomy late in obstructed labor, the junction of the two segments is not a noticeable thing and it certainly does not project on the surface of the uterus. Such operations are rare in this country, but Dr. Mahmoud Ismail Bey, Professor of Obstetrics in the University of Cairo, in a personal letter, says, "As regards my opinion about the 'projecting' ring :If Bandl at the junction of the upper and the lower segment, I can say that I have done cesarean sections often for women long in labor in whom the lower segment was overstretched but I did not notice or feel such a projecting ring. In many eases the top of the blander wn.s high enough to be felt as a ridge.'' '!'here are several excellent speeimenP
Fig. 1.
Fig. 2
Figs, 1 and 2.-Two >!ketches from a postmortem specimen to show that the rlng of Bancll does not form a palpable rtdge but the raised edematous bladder does form an easily palpable mass which rises during labor. of the uterus in tonic retraction in the famous .Mahfous collection in the museum of the Kasr el Aini .Medical School in Cairo, which confirm my views that it is improbable that a.nyone has ever palpa.ted the junction of the upper with the lower segment or felt it as a projecting ridge. Yet, for years it was taught that the retraction ring could be palpated through the abdominal wall and could be noticed to rise higher and higher in the lower a.bdomen while the patient was watched. In my opinion the ridge which they palpated was the top of the edematous bladder which is attached to the lower segment and would certainly be found to get higher as the obstructed labor progressed. Figs. 1 and 2 from a postmortem specimen in the Mahfous collection show that this is the truth. The upper segment having become retracted and thick and the lower segment thinned, nothing will get them back to their normal state except the delivery of the baby and the involution of the uterus. No drug could possibly alter this condition back to the normal ani!, thus, as a corollary, if the use of a drug such as morphine appears to alter a
Volume S7 Number 2
COR.RESPONDJ<;NCE
4-09
tonically retracted uterus into a normally acting one, it immediately proves that the uteru~ was not tonically retracted but that some other condition, such as an irritated uterus, was present. Morphine is most valuable in slowing uterine action and thus preventing tho rapid progress of retraction but it cannot alter the condition already established. If this is recognized, it will prevent people from stating that tonic retraction has been cured by any treatment other than the removal of the fetus that was splinting the uterine cavity.
Fig. 3. Fig. 4. Fig. 3.-Meslal sagittal section ot uterus with fetus In situ. The child was presenting by the shoulder, and 'a toot had been brought down in an unsuccessful attempt to perform version. The contraction ring can be seen running obliquely across the uterus. The upper uterine segment Is not thickened and the presenting part was not fixed in the brim of the pelvis. Fig. 4.-Meslal sagittal section of uterus removed during labor, showing contraction ring which caused dystocia. The end of untreated obstructed labor is death, either from exhaustion or from rupture of the uterus; it is perhaps justifiable to regard tonic retraction as Nature 'a method of killing fairly quickly a patient with an insuperable obstacle to delivery. For· tunately, secondary uterine inertia does not occur in the second stage of a labor complicated by bony obstruction; if it did, the patient's agony would be prolonged for man~· days. Yet any examiner knows how frequently students state that there are two alterna· tives in a case of obstructed labor, either tonic retraction or ~econdary uterine inertia. Luckily, the statement is not true.
CORRESPONDENCE
410
Am. J. Obst. & Gynec. February, 1949
1'extbooks tell us that one of the causes of tonic retraction is the use of stimulants to uterine action, such as ergot or Pitocin, but this is improbable. Tonic retraction is essentially a slow process and insidious in its onset, whereas the action of Pitocin is prompt. It is possible that oxytocic drugs may increase the force of uterine contractions and so, in the presence of an obstacle to delivery, make the onset of obstructed labor quicker than it otherwise would have been, but that is all. In the absence of disproportion, all that oxytocics could do would be to produce an irritated uterus, i.e., a generally contracted uterus where the whole uterus is contracted but there is not any thinning of the lower segment. Another way in which a generally contracted (irritated) uterus can be produced is by manipulations, for example, when attempts are made to dilate the cervix manually or when the foreeps is applied to the head above the brim and unsuccessful efforts made to deliver the child. In such patients, it is sometimes found that the uterus does not relax and such a case can easily be mistaken for one of tonic retraction, but, after an interval, the uterus is found to be contracting and relaxing normally. A little consideration will show that tonic retraction could not have been present in such patients because it comes on gradually and is never followed by relaxation or by normal uterine action; also, the lower segment is not thinned or tense and the general condition of a patient with a generally contracted uterus remains good. Morphine will assist an irritated uterus to become normal again more quickly than it otherwise would. Although the longcontinued contraction of the irritated uterus makes it feel hard, the contraction does not seem sufficient always entirely to stop the circulation through the placental site and so a living child may be obtained after an interval. In tonic retraction the circulation through the placental site has failed and so the child is dead. A contraction ring is a localized contraction of the uterus which frequently forms over a depression in the child's outline but may be below the child. It occurs in the first. second, and third stages of labor and even before there are signs that labor has started. Hence, it is not the result of labor obstructed by disproportion, and, if disproportion hap· pens to be present, its presence is a coincidence and not a causal factor. The body of the uterus above the ring continues to contract and relax as in a normal labor. The patient's general condition is quite good-several of my patients had a pulse rate of 80. The circu· lation through the placental site is maintained and so the child is alive. The cause of the condition is obscure; the causes mentioned in my original article are not truly etiological factors. A contraction ring does cause delay in labor. Occasionally a contraction ring can be palpated through the abdominal wall as a depression running across the lower part of the uterus. It is usually tender and some· times the patient states that she notices the discomfort of a uterine contraction first in the region of the ring. If the head is presenting, it is lifted up during a pain and so becomes more mobile from side to side as first described by Gilliatt. On vaginal examination, signs of disproportion are absent. In the majority of cases, the failure of traction by the for· ceps is the first thing to show that an abnormality is present. Moreover, when the for· ceps has drawn the head down, it recedes to its original level in the pelvis as soon as traction is stopped. The reason for this recession of the head is that the forceps pulls down the whole uterus containing the child and the resilience of the cardinal ligaments takes the uterus and its contents back to their original level as soon as traction is stopped. In a similar way, the head does not descend during a pain. These signs are an indication for passing the hand into the uterus when the ring will probably be felt round the child's neck. The treatment of contraction rings has been fully discussed by Rudolph in variouR papers and so will not be further touched on here. CLIFFORD WHITE.
97 HARLEY STREET, LONDON W 1. 1. Rudolph, Louis, and Fields, Charles: AM. J. OBST. & GYNEC. 53: 7!l6, l!l47. 2. Rucker, Pierce: J. Mt. Sinai Hosp. 14: 576, 1947.
407
UO.URESPUN DEN CE
Am. j. Obot. a Gyno.. February, 194Q
rwt any projection on the peritoneal aspect and nothing that could be palpated. During a laparotomy late in obstructed labor, the junction of the two segments is not a noticeable thing and it certainly does not project on the surface of the uterus. Such operations are rare in this country, but Dr. Mahmoud Ismail Bey, Professor of Obstetrics in the University of Cairo, in a personal letter, says, "As regards my opinion about the 'projecting' ring :If Bandl at the junction of the upper and the lower segment, I can say that I have done cesarean sections often for women long in labor in whom the lower segment was overstretched but I did not notice or feel such a projecting ring. In many eases the top of the blander wn.s high enough to be felt as a ridge.'' '!'here are several excellent speeimenP
Fig. 1.
Fig. 2
Figs, 1 and 2.-Two >!ketches from a postmortem specimen to show that the rlng of Bancll does not form a palpable rtdge but the raised edematous bladder does form an easily palpable mass which rises during labor. of the uterus in tonic retraction in the famous .Mahfous collection in the museum of the Kasr el Aini .Medical School in Cairo, which confirm my views that it is improbable that a.nyone has ever palpa.ted the junction of the upper with the lower segment or felt it as a projecting ridge. Yet, for years it was taught that the retraction ring could be palpated through the abdominal wall and could be noticed to rise higher and higher in the lower a.bdomen while the patient was watched. In my opinion the ridge which they palpated was the top of the edematous bladder which is attached to the lower segment and would certainly be found to get higher as the obstructed labor progressed. Figs. 1 and 2 from a postmortem specimen in the Mahfous collection show that this is the truth. The upper segment having become retracted and thick and the lower segment thinned, nothing will get them back to their normal state except the delivery of the baby and the involution of the uterus. No drug could possibly alter this condition back to the normal ani!, thus, as a corollary, if the use of a drug such as morphine appears to alter a
Volume S7 Number 2
COR.RESPONDJ<;NCE
4-09
tonically retracted uterus into a normally acting one, it immediately proves that the uteru~ was not tonically retracted but that some other condition, such as an irritated uterus, was present. Morphine is most valuable in slowing uterine action and thus preventing tho rapid progress of retraction but it cannot alter the condition already established. If this is recognized, it will prevent people from stating that tonic retraction has been cured by any treatment other than the removal of the fetus that was splinting the uterine cavity.
Fig. 3. Fig. 4. Fig. 3.-Meslal sagittal section ot uterus with fetus In situ. The child was presenting by the shoulder, and 'a toot had been brought down in an unsuccessful attempt to perform version. The contraction ring can be seen running obliquely across the uterus. The upper uterine segment Is not thickened and the presenting part was not fixed in the brim of the pelvis. Fig. 4.-Meslal sagittal section of uterus removed during labor, showing contraction ring which caused dystocia. The end of untreated obstructed labor is death, either from exhaustion or from rupture of the uterus; it is perhaps justifiable to regard tonic retraction as Nature 'a method of killing fairly quickly a patient with an insuperable obstacle to delivery. For· tunately, secondary uterine inertia does not occur in the second stage of a labor complicated by bony obstruction; if it did, the patient's agony would be prolonged for man~· days. Yet any examiner knows how frequently students state that there are two alterna· tives in a case of obstructed labor, either tonic retraction or ~econdary uterine inertia. Luckily, the statement is not true.
CORRESPONDENCE
410
Am. J. Obst. & Gynec. February, 1949
1'extbooks tell us that one of the causes of tonic retraction is the use of stimulants to uterine action, such as ergot or Pitocin, but this is improbable. Tonic retraction is essentially a slow process and insidious in its onset, whereas the action of Pitocin is prompt. It is possible that oxytocic drugs may increase the force of uterine contractions and so, in the presence of an obstacle to delivery, make the onset of obstructed labor quicker than it otherwise would have been, but that is all. In the absence of disproportion, all that oxytocics could do would be to produce an irritated uterus, i.e., a generally contracted uterus where the whole uterus is contracted but there is not any thinning of the lower segment. Another way in which a generally contracted (irritated) uterus can be produced is by manipulations, for example, when attempts are made to dilate the cervix manually or when the foreeps is applied to the head above the brim and unsuccessful efforts made to deliver the child. In such patients, it is sometimes found that the uterus does not relax and such a case can easily be mistaken for one of tonic retraction, but, after an interval, the uterus is found to be contracting and relaxing normally. A little consideration will show that tonic retraction could not have been present in such patients because it comes on gradually and is never followed by relaxation or by normal uterine action; also, the lower segment is not thinned or tense and the general condition of a patient with a generally contracted uterus remains good. Morphine will assist an irritated uterus to become normal again more quickly than it otherwise would. Although the longcontinued contraction of the irritated uterus makes it feel hard, the contraction does not seem sufficient always entirely to stop the circulation through the placental site and so a living child may be obtained after an interval. In tonic retraction the circulation through the placental site has failed and so the child is dead. A contraction ring is a localized contraction of the uterus which frequently forms over a depression in the child's outline but may be below the child. It occurs in the first. second, and third stages of labor and even before there are signs that labor has started. Hence, it is not the result of labor obstructed by disproportion, and, if disproportion hap· pens to be present, its presence is a coincidence and not a causal factor. The body of the uterus above the ring continues to contract and relax as in a normal labor. The patient's general condition is quite good-several of my patients had a pulse rate of 80. The circu· lation through the placental site is maintained and so the child is alive. The cause of the condition is obscure; the causes mentioned in my original article are not truly etiological factors. A contraction ring does cause delay in labor. Occasionally a contraction ring can be palpated through the abdominal wall as a depression running across the lower part of the uterus. It is usually tender and some· times the patient states that she notices the discomfort of a uterine contraction first in the region of the ring. If the head is presenting, it is lifted up during a pain and so becomes more mobile from side to side as first described by Gilliatt. On vaginal examination, signs of disproportion are absent. In the majority of cases, the failure of traction by the for· ceps is the first thing to show that an abnormality is present. Moreover, when the for· ceps has drawn the head down, it recedes to its original level in the pelvis as soon as traction is stopped. The reason for this recession of the head is that the forceps pulls down the whole uterus containing the child and the resilience of the cardinal ligaments takes the uterus and its contents back to their original level as soon as traction is stopped. In a similar way, the head does not descend during a pain. These signs are an indication for passing the hand into the uterus when the ring will probably be felt round the child's neck. The treatment of contraction rings has been fully discussed by Rudolph in variouR papers and so will not be further touched on here. CLIFFORD WHITE.
97 HARLEY STREET, LONDON W 1. 1. Rudolph, Louis, and Fields, Charles: AM. J. OBST. & GYNEC. 53: 7!l6, l!l47. 2. Rucker, Pierce: J. Mt. Sinai Hosp. 14: 576, 1947.