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Risks in breech delivery associated with fetal size and the induction of labor
Risks in breech delivery associated with fetal size and the induction of labor CLYDE L. RANDALL, M.D. RICHARD W. BAETZ, M.D. JOSEPH R. BRANDY, M.D. Buffalo, New York
version is never attempted by many obstetricians of considerable experience. In this regard, Vartan 7 has long emphasized a rather practical concept. At 32 to 34 weeks' gestation, if examinations have been made frequently, he believes that the fetus can be found to be presenting by the breech in at least 20 per cent of cases. Vartan believes that breech presentations spontaneously convert to vertex by the onset of labor in all but about 3 per cent of the pregnancies which go to term. Those who have practiced routine attempts at external version seem agreed that in 10 to 15 per cent of cases they are unable to convert the breech to a vertex by external version. We are tempted to conclude, therefore, that about the same proportion of breech presentations which can be converted to vertex by the techniques of external version can also be expected to convert spontaneously to a vertex before the onset of labor if pregnancy goes to term. The ones that persist as breech presentations may be the ones in which version would not have been successful anyway. With Vartan's concept in mind, we have admittedly neglected to develop the art of external version. Consideration of the risks of breech delivery have long emphasized the advantages and disadvantages of the routine practice of assisting the frank breech as soon as full dilatation has been accomplished as compared with the practice of permitting the delivery
T H E risks inherent in breech delivery are well known and are hardly lessened by the mere parity of the patient to be delivered. Dr. Baetz' 2 • 3 most recent summary of the causes of fetal deaths as related to the type of delivery in 7 cooperating Buffalo hospitals records the fetal mortality observed in approximately 250,000 deliveries. When all the correctable causes of fetal loss have been deducted, namely, ( 1) the nonviable premature infants (until 1955 under 1,500 grams, since 1955 under 1,000 grams); (2) the antepartum deaths (macerated infants); and (3) the infants born with congenital abnormalities incompatible with life, the 4 per cent breech deliveries continue to be associated with more than 25 per cent of our total fetal loss. Actually, breech delivery was associated with 24.6 per cent of the corrected fetal loss in 1957, 24.1 per cent in 1958, and nearly 30 per cent in 1959. Conversion of the persistent breech to a vertex presentation by external version before the onset of labor has long been advocated. While this procedure continues to be employed routinely in some areas, external From the Department of Obstetrics and Gynecology, University of Buffalo School of Medicine and the Buffalo General Hospital. Guest Speaker's Address, presented at the Sixteenth Annual Meeting of the Society of Obstetricians and Gynaecologists of Canada, Jasper, Alberta, June 10-12, 1960.
27
28
Randall, Baetz, and Brandy
to proceed spontaneously until the umbilicus appears at the introitus. The influence of varying types of anesthesia and the importance of the judgment and skill of an experienced obstetrician have often been emphasized. The risk of breech delivery is apparently less in the hands of the experienced specialist, but is likely to be manifest in the teaching services when delivery is managed by students, interns, and residents. In the Buffalo area, Potter's 5 • 6 definition of the factors accounting for difficulties during breech delivery has contributed greatly to an increased interest in and respect for the risks inherent in breech delivery at term. Perhaps the majority of obstetricians, however, are not yet willing to regard breech presentation alone as adequate indication for elective cesarean section in the nullipara. Many insist that the ability to manage a breech presentation successfully should be regarded as one of the fundamentals to be acquired by the obstetrical specialist. For years we assumed that we could gather data justifying the acceptance of some fetal loss associated with breech delivery at term in a primigravida for the sake of preserving an unscarred myometrium. It was our conviction that a woman whose first pregnancy resulted in breech delivery was no more likely than the average multipara to have a breech presentation at term in subsequent pregnancies. Actual findings were quite contrary to our expectations. Although Baetz 1 noted that the incidence of breech delivery among primigravidas was approximately 4 per cent, he found that the incidence of a second breech presentation was approximately 21 per cent. It seemed evident, therefore, that the factors accounting for breech presentation, at least among those women who had a breech delivery at term as primigravidas, are factors that can be expected to persist and predispose to a breech presentation at term in subsequent pregnancies. In recent years, the practice of routine exploration of the uterine cavity immediately after the expulsion of the placenta has suggested the probability that irregularities in
A111.
J
.July, 1%1 Ohst. & Cyn<'c
the contour of the uterine cavity, particularly the presence of incomplete "doubling" or septae in the fundus, arc associated with breech presentation in a significant proportion of cases. Consideration of the problems inherent in the management of breech presentation might well continue, therefore, to take into account the probability that the woman whose first baby presents as a breech at term will be likely in subsequent pregnancies to again have a breech presentation at term. Contrary to what is perhaps a rather general impression, our records also indicate that the fetal loss associated with breech delivery at term in the multipara is not significantly less than that associated with breech presentation at term in the woman's first pregnancy. If elective cesarean section is the safest way to deliver the primigravida with a breech presentation at term, it must also be the safest way to deliver the multipara with a breech presentation at term. A visiting Professor at the University of Buffalo, Dr. Arthur Sutherland of Glasgow, recently expressed the conviction that the difficulties in breech delivery could be minimized by elective induction of labor as soon as the fetus was thought to weigh sy2 to 6 pounds. Our interest in his suggestion was increased by the fact that elective induction of labor had in recent years become a frequently employed procedure by a number of the obstetricians in the Buffalo area. As a result of this experience, it seemed evident to us that the risks inherent in the elective induction of labor could be reduced if care is taken to make certain that the labor is not initiated while the child is still premature. Rupture of the membranes when there is maternal or fetal indication to terminate the pregnancy is recognized as the most certain and dependable method of initiating labor. 4 As a means of initiating purely electivP induction, however, we continue to feel that such initial rupture of the membranes is not wise. With the breech presenting, rupture of the membranes before the onset of labor. whether this occurs spontaneously or is done electively, increases the risk of a
Volume 82 Number I
prolapsed cord. With the vertex "a little high:' rupture of the membranes, particularly when the fetus is "a lit.tle small," increases the risk of a compound or unfavorable presentation. With vertex or breech presenting, initial rupture of the membranes is not infrequently associated with the maternal risks inherent in an undesirably long latent period. We think, therefore, that each elective induction should be approached with the feeling that the attempt to initiate labor will, to a considerable extent, be only a therapeutic test to see if the pregnancy is really at term and the uterus easily stimulated to contract. When an infusion of an oxytocic initiates contractions which bring about effacement and dilatation of the cervix, we have reason to feel that, from the standpoint of function, the placenta has served its purpose and the baby is as large as it is going to be. Assuming that placental function is more likely to be keeping the uterus refractory to oxytocics before term than later when both fetus and placenta are "ripe" for induction, we have been proceeding on the theory that we will not be as likely to initiate labor when the infant is still premature if we first see what the effect of an infusion of dilute Pitocin will be before we consider rupture of the membranes. If the uterus fails to respond, we might well conclude that the uterus is not ready for induction. If we then change our mind, convince the patient that labor should not be induced immediately, and send her horne, no harm has been done. If the membranes have been ruptured, however, our steps cannot be retraced. Whether we recognize postmaturity as an entity or not, at times pregnancy seems to have continued until the placenta proves unable to supply the fetus with sufficient oxygen for it to survive the effects of the frequent long contractions characteristic of the "overdue'' labor. In such cases, we could have been serving the babies' best interests if we had electively initiated labor at an earlier date. Induction could in this manner be indicated, in a prophylactic sense, but we believe such benefit is likely to be accomplished only
Risks in breech delivery 29
if we restrict our efforts to induce labor to those instances in which we find that it can be done easily. Consider then the proposal to induce labor when breech presentation persists, as a means of assuring delivery of the baby before it becomes as large as it may if the spontaneous onset of labor is awaited. Our interest in this suggestion was increased by previous conviction that the risks inherent in any elective induction of labor would be more likely to be realized if labor is initiated when a small fetus is in the breech position, particularly if the induction is started by elective rupture of the membranes. Shortly before Dr. Sutherland's visit, a review4 of the elective induction of labor in two Buffalo hospitals had indicated breech presentation was a contraindication to such elective induction. Dr. Sutherland's proposal was not simply to elect induction in spite of breech presentation, but, rather, that induction of labor, when breech presentation persists, should be undertaken as a considered effort to reduce the fetal loss or injury incident to breech delivery. Before we could agree, we decided to look for evidence that the smaller babies presenting by the breech are more easily and more safely managed during labor and delivery. The recommendation of induction before term was a disturbing idea because for years we had taught that a relatively big baby in breech presentation, particularly frank breech, could be expected to dilate the cervix and birth canal adequately and thus facilitate delivery of the aftercoming head. When the baby seemed large, we had assumed that delivery of the aftercoming head would be relatively easy. With these possibilities in mind, we were prompted to review again the risks associated with breech delivery which seem particularly related to fetal size. Case records were surveyed in order to compare the results of breech delivery when the babies weighed between 5 and 6 pounds with the results when the babies weighed more than 7 pounds. In these data, we have disregarded the frequency of fetal injury and morbidity, frac-
30
Randall, Baetz, and Brandy
July, l'!lil
\111 •
tures of fetal extremities, InJuries of the brachial plexus, and later evidence of cerebrospastic disease or mental retardation. This omission is due to our own conviction that such injury to the fetus usually occurs when the delivery is managed by a relatively inexperienced operator. In gathering these data, we have attempted to compare results that could hardly be altered by the experience and technical skill of the obstetrician. In the Buffalo General Hospital during the 10 years 1949 to 1958 there were a total of 20,162 deliveries including 4 79 breech presentations in which the baby weighed over 5 pounds at birth. This number of breech deliveries at or near term represented 2.4 per cent of the deliveries in this hospital during the 10 year period surveyed. In 90, or 18.8 per cent, of the 479 breech deliveries reviewed, the baby weighed between 5 and 6 pounds. In approximately one half of all breech presentations (234 of the 479 babies), the newborn infant weighed over 7 pounds. The frank breech was the most frequent type, and, somewhat to our surprise, the size of the fetus was found to have no appreciable effect on the relative frequency of a frank breech presentation. In 259 of the 479 cases (54.1 per cent of the breech deliveries), the fetus presented as a frank breech. Of 90 cases in which the baby weighed 5 to 6 pounds at birth, 50, or 55 per cent, involved a frank breech presentation. Of the 234 cases in which the baby weighed over 7 pounds at birth, 127, or 54.3 per cent, involved a frank breech presentation. Footling or compound presentation was also not more frequent among either the larger or the smaller babies. There seemed to be no concentration of factors increasing the risk to the fetus in either the smaller ( 5 to 6 pounds) or the larger (over 7 pounds) group, other than those factors which would be expected to be related to the birth of relatively large or relatively small babies. For this reason, we thought it reasonable not to attempt to "correct" our figures for such factors as premature rupture of the membranes, precipitate labor, or multiparity. The outcome was to some extent influenced
.f. <)IJ,t. & Gyn<:e.
by those secondary factors associated with fetal size. It is evident. for instance, that, when breech presentation persists, spontaneous premature rupture of the membranes is more likely. With the breech presenting, a relatively longer latent period between such premature spontaneom rupture of the membranes and the onset of labor can be expected, and this latent p<:>riod is likely to be longer when the babies are smaller. In 64 cases in which the baby weighed between 5 and 6 pounds, it was found that the time between premature rupture of the membranes and the onset of labor averaged 15.1 hours compared to an average of only 9.CJ hours in 195 cases of breech delivery following premature rupture of the membranes when the babies all weighed over 7 pounds. A relatively longer period of total time in the labor room, in the presence of a small baby, might be at least partially due to the relative unripeness of the cervix and unresponsiveness of the myometrium. Among our own cases, however, we did not find the correlation we had expected between the length of labor and the size of the baby. In the primigravidas, when the baby presenting by the breech weighed between 5 and 6 pounds, labor averaged 11.4 hours compared to 18.3 hours when the baby weighed more than 7 pounds. When the mother was a multipara and the baby weighed between 5 and 6 pounds, breech labors averaged 8.8 hours compared to 9.9 hours when the baby weighed more than 7 pounds. The second stage of labor in the primigravida averaged 57.3 minutes when the baby weighed between 5 and 6 pounds and averaged nearly twice that, or 191.5 minutes, when the baby weighed more than 7 pounds. When a multipara had a breech presentation, the second stage of labor averaged 32 minutes when the baby weighed 5 to 6 pounds and 38.6 minutes when the baby weighed over 7 pounds. Cesarean section was elected before the onset of labor in 1.2 per cent of the cases when the baby weighed between :) and 6 pounds and in 4.8 per cent of the cases when
Risks in breech delivery 31
Volume 82 Numht·r 1
the baby weighed over 7 pounds. Among the mothers of smaller babies, 2.5 per cent were delivered by cesarean section after there seemed to be no progress in labor, but when the babies weighed more than 7 pounds at birth 3.5 per cent of the mothers were delivered by cesarean section because labor did not progress. There was no evidence of a greater risk of prolapse of the cord with the smaller ( 5 to 6 pounds) babies than with the larger (over 7 pounds) babies. In 5 of the 12 cases in which prolapse of the cord became evident (or 40 per cent), this complication was first recognized during the second stage of labor. Breech delivery was completed "without difficulty" in 85 per cent of the cases when the baby weighed between 5 and 6 pounds, and with no difficulty in only 70 per cent of the cases when the baby weighed over 7 pounds. Greater difficulty with larger babies is evidenced also in the fact that Piper forceps were used in 12 per cent of the deliveries of the smaller babies and in 21 per cent of the cases when the baby weighed over 7 pounds at birth. It must be admitted, however, that the Piper forceps were at times regarded as a means of affording protection to the aftercoming head of an obviously small fetus, whereas the forceps were not likely to have been elected in the birth of the relatively larger babies for any such purely prophylactic consideration. Niswander and Patterson 4 have recently reviewed the records of 1,000 consecutive labors which were electively induced during the past 3 years in the Children's and Buffalo General Hospitals. Among the labors reviewed were 22 cases in which the persistence of a breech presentation had apparently not been recognized when the decision was made to induce labor. The outcome in these 22 cases in which labor was electively induced with the breech presenting has been the subject of much local interest. There were 2 babies in the 5 to 6 pound group. One had no difficulty. In the other the cord prolapsed and, although a cesarean section was performed promptly, the baby
did not survive. There were 8 babies in the 6 to 7 pound group. Seven had no difficulty, but one presented as a footling, the cervix dilated rapidly, delivery of the aftercoming head was considered difficult, and the child did not survive. There were 12 babies in the group weighing more than 7 pounds at birth; there was no difficulty with the delivery of any of the 12, and alt survived without complication. Among the cases of breech delivery managed at the Buffalo General Hospital between 1949 and 1958, smaller babies seem more frequently associated with fetai ioss. Among the 90 cases of breech delivery when the babies weighed 5 to 6 pounds, the gross loss was 6.66 per cent, correctable to a fetal mortality of 3.33 per cent. This loss among the smaller babies with breech presentation, seems high considering the fact that the corrected fetal mortality, when only babies weighing over 7 pounds were considered, was 1. 7 per cent in a total of 234 breech deliveries at term. It is evident that we may be maintaining a conviction upon the basis of two sets of rather meager data. When labor was electively induced in 22 cases of breech presentation, one of the 2 babies weighing between 5 and 6 pounds and one of the 8 babies weighing between 6 and 7 pounds died, while all of the 12 weighing more than 7 pounds survived without difficulty. In only 2 of those 22 babies with breech presentation was labor induced when the baby weighed under 6 pounds, but in one of the 2 the cord prolapsed and the fetus did not survive. Although this is only a single case, it nevertheless seems a good example of the fact that when the breech is presenting and labor begins when the baby is still small and before it is well down into the pelvis, accidents seem more likely to happen. Comment
Cases studied are but few, even with a review of breech deliveries in the Buffalo General Hospital during the past 10 years. Can we draw conclusions based on the fate of only 7 babies among the 324 breech de-
July, 1Y!>l
32 Randall, Baetz, and Brandy
liveries considered? What would have happened to our conviction if we had lost 2 instead of 3 among the 90 babies weighing between 5 and 6 pounds, and lost 5 instead of 4 among those weighing more than 7 pounds? Such a shift involving realignment of but one of the 7 fetal deaths would, of course, have reduced the deaths among the smaller babies by 33 per cent and increased the deaths among the larger babies by 25 per cent. The loss of 2 among 90 smaller babies would have meant a fetal mortality of 2.2 per cent for the 5 to 6 pound group, and the loss of 5 babies instead of 4 among the group weighing more than 7 pounds would have meant a fetal mortality of 2.1 per cent for the larger babies. This would seem to suggest that there will have to be more than a 14 per cent shift in the fetal loss from the smaller to the larger baby groups before we could provide data that would make efforts
REFERENCES
1. Baetz, R. W., and Randall, C. L.: New York J. Med. 48: 49, 1948. 2. Baetz, R. W.: New York J. Med. 55: 2627, 1955. 3. Baetz, R. W.: Unpublished annual reports to the Buffalo Obstetrical and Gynecological Society. 4. Niswander, K. R., Patterson, R. J, and Ran-
Am. j. Ob"t. & Gynec.
to assure delivery of relatively smaller babies seem advisable. Summary
From our data, a comparison of the difficulties experienced with breech deliveries when the babies are small ( 5 to 6 pounds) and those when the babies weigh more than 7 pounds, three conclusions may be reached: 1. With the smaller babies, there was no increased incidence of prolapse of the cord and no increased incidence of unfavorable footling presentations. 2. With the smaller babies, labor was less frequently difficult and less likely to terminate in cesarean section after a few hours of ineffectual contractions. 3. We can find no reason to believe, however, that we could reduce the frequency of the fatal complications of breech delivery by inducing labor when we think the baby will weigh between 5 and 6 pounds.
dall, C. L.: AM. J. OasT. & GYNEC. 79: 797, 1960. 5. Potter, Milton, G.: Proc. First American Gong. Obst. & Gynec. 1: 343, 1940. 6. Potter, Milton G., Ervin, Henry, and Brown. ]. Bruce: AM. J. OasT. & GYNEC. 49: 567, 1945. 7. Vartan, C. Keith: J. Obst. & Gynaec. Brit Emp. 52: 417, 1945.
version is never attempted by many obstetricians of considerable experience. In this regard, Vartan 7 has long emphasized a rather practical concept. At 32 to 34 weeks' gestation, if examinations have been made frequently, he believes that the fetus can be found to be presenting by the breech in at least 20 per cent of cases. Vartan believes that breech presentations spontaneously convert to vertex by the onset of labor in all but about 3 per cent of the pregnancies which go to term. Those who have practiced routine attempts at external version seem agreed that in 10 to 15 per cent of cases they are unable to convert the breech to a vertex by external version. We are tempted to conclude, therefore, that about the same proportion of breech presentations which can be converted to vertex by the techniques of external version can also be expected to convert spontaneously to a vertex before the onset of labor if pregnancy goes to term. The ones that persist as breech presentations may be the ones in which version would not have been successful anyway. With Vartan's concept in mind, we have admittedly neglected to develop the art of external version. Consideration of the risks of breech delivery have long emphasized the advantages and disadvantages of the routine practice of assisting the frank breech as soon as full dilatation has been accomplished as compared with the practice of permitting the delivery
T H E risks inherent in breech delivery are well known and are hardly lessened by the mere parity of the patient to be delivered. Dr. Baetz' 2 • 3 most recent summary of the causes of fetal deaths as related to the type of delivery in 7 cooperating Buffalo hospitals records the fetal mortality observed in approximately 250,000 deliveries. When all the correctable causes of fetal loss have been deducted, namely, ( 1) the nonviable premature infants (until 1955 under 1,500 grams, since 1955 under 1,000 grams); (2) the antepartum deaths (macerated infants); and (3) the infants born with congenital abnormalities incompatible with life, the 4 per cent breech deliveries continue to be associated with more than 25 per cent of our total fetal loss. Actually, breech delivery was associated with 24.6 per cent of the corrected fetal loss in 1957, 24.1 per cent in 1958, and nearly 30 per cent in 1959. Conversion of the persistent breech to a vertex presentation by external version before the onset of labor has long been advocated. While this procedure continues to be employed routinely in some areas, external From the Department of Obstetrics and Gynecology, University of Buffalo School of Medicine and the Buffalo General Hospital. Guest Speaker's Address, presented at the Sixteenth Annual Meeting of the Society of Obstetricians and Gynaecologists of Canada, Jasper, Alberta, June 10-12, 1960.
27
28
Randall, Baetz, and Brandy
to proceed spontaneously until the umbilicus appears at the introitus. The influence of varying types of anesthesia and the importance of the judgment and skill of an experienced obstetrician have often been emphasized. The risk of breech delivery is apparently less in the hands of the experienced specialist, but is likely to be manifest in the teaching services when delivery is managed by students, interns, and residents. In the Buffalo area, Potter's 5 • 6 definition of the factors accounting for difficulties during breech delivery has contributed greatly to an increased interest in and respect for the risks inherent in breech delivery at term. Perhaps the majority of obstetricians, however, are not yet willing to regard breech presentation alone as adequate indication for elective cesarean section in the nullipara. Many insist that the ability to manage a breech presentation successfully should be regarded as one of the fundamentals to be acquired by the obstetrical specialist. For years we assumed that we could gather data justifying the acceptance of some fetal loss associated with breech delivery at term in a primigravida for the sake of preserving an unscarred myometrium. It was our conviction that a woman whose first pregnancy resulted in breech delivery was no more likely than the average multipara to have a breech presentation at term in subsequent pregnancies. Actual findings were quite contrary to our expectations. Although Baetz 1 noted that the incidence of breech delivery among primigravidas was approximately 4 per cent, he found that the incidence of a second breech presentation was approximately 21 per cent. It seemed evident, therefore, that the factors accounting for breech presentation, at least among those women who had a breech delivery at term as primigravidas, are factors that can be expected to persist and predispose to a breech presentation at term in subsequent pregnancies. In recent years, the practice of routine exploration of the uterine cavity immediately after the expulsion of the placenta has suggested the probability that irregularities in
A111.
J
.July, 1%1 Ohst. & Cyn<'c
the contour of the uterine cavity, particularly the presence of incomplete "doubling" or septae in the fundus, arc associated with breech presentation in a significant proportion of cases. Consideration of the problems inherent in the management of breech presentation might well continue, therefore, to take into account the probability that the woman whose first baby presents as a breech at term will be likely in subsequent pregnancies to again have a breech presentation at term. Contrary to what is perhaps a rather general impression, our records also indicate that the fetal loss associated with breech delivery at term in the multipara is not significantly less than that associated with breech presentation at term in the woman's first pregnancy. If elective cesarean section is the safest way to deliver the primigravida with a breech presentation at term, it must also be the safest way to deliver the multipara with a breech presentation at term. A visiting Professor at the University of Buffalo, Dr. Arthur Sutherland of Glasgow, recently expressed the conviction that the difficulties in breech delivery could be minimized by elective induction of labor as soon as the fetus was thought to weigh sy2 to 6 pounds. Our interest in his suggestion was increased by the fact that elective induction of labor had in recent years become a frequently employed procedure by a number of the obstetricians in the Buffalo area. As a result of this experience, it seemed evident to us that the risks inherent in the elective induction of labor could be reduced if care is taken to make certain that the labor is not initiated while the child is still premature. Rupture of the membranes when there is maternal or fetal indication to terminate the pregnancy is recognized as the most certain and dependable method of initiating labor. 4 As a means of initiating purely electivP induction, however, we continue to feel that such initial rupture of the membranes is not wise. With the breech presenting, rupture of the membranes before the onset of labor. whether this occurs spontaneously or is done electively, increases the risk of a
Volume 82 Number I
prolapsed cord. With the vertex "a little high:' rupture of the membranes, particularly when the fetus is "a lit.tle small," increases the risk of a compound or unfavorable presentation. With vertex or breech presenting, initial rupture of the membranes is not infrequently associated with the maternal risks inherent in an undesirably long latent period. We think, therefore, that each elective induction should be approached with the feeling that the attempt to initiate labor will, to a considerable extent, be only a therapeutic test to see if the pregnancy is really at term and the uterus easily stimulated to contract. When an infusion of an oxytocic initiates contractions which bring about effacement and dilatation of the cervix, we have reason to feel that, from the standpoint of function, the placenta has served its purpose and the baby is as large as it is going to be. Assuming that placental function is more likely to be keeping the uterus refractory to oxytocics before term than later when both fetus and placenta are "ripe" for induction, we have been proceeding on the theory that we will not be as likely to initiate labor when the infant is still premature if we first see what the effect of an infusion of dilute Pitocin will be before we consider rupture of the membranes. If the uterus fails to respond, we might well conclude that the uterus is not ready for induction. If we then change our mind, convince the patient that labor should not be induced immediately, and send her horne, no harm has been done. If the membranes have been ruptured, however, our steps cannot be retraced. Whether we recognize postmaturity as an entity or not, at times pregnancy seems to have continued until the placenta proves unable to supply the fetus with sufficient oxygen for it to survive the effects of the frequent long contractions characteristic of the "overdue'' labor. In such cases, we could have been serving the babies' best interests if we had electively initiated labor at an earlier date. Induction could in this manner be indicated, in a prophylactic sense, but we believe such benefit is likely to be accomplished only
Risks in breech delivery 29
if we restrict our efforts to induce labor to those instances in which we find that it can be done easily. Consider then the proposal to induce labor when breech presentation persists, as a means of assuring delivery of the baby before it becomes as large as it may if the spontaneous onset of labor is awaited. Our interest in this suggestion was increased by previous conviction that the risks inherent in any elective induction of labor would be more likely to be realized if labor is initiated when a small fetus is in the breech position, particularly if the induction is started by elective rupture of the membranes. Shortly before Dr. Sutherland's visit, a review4 of the elective induction of labor in two Buffalo hospitals had indicated breech presentation was a contraindication to such elective induction. Dr. Sutherland's proposal was not simply to elect induction in spite of breech presentation, but, rather, that induction of labor, when breech presentation persists, should be undertaken as a considered effort to reduce the fetal loss or injury incident to breech delivery. Before we could agree, we decided to look for evidence that the smaller babies presenting by the breech are more easily and more safely managed during labor and delivery. The recommendation of induction before term was a disturbing idea because for years we had taught that a relatively big baby in breech presentation, particularly frank breech, could be expected to dilate the cervix and birth canal adequately and thus facilitate delivery of the aftercoming head. When the baby seemed large, we had assumed that delivery of the aftercoming head would be relatively easy. With these possibilities in mind, we were prompted to review again the risks associated with breech delivery which seem particularly related to fetal size. Case records were surveyed in order to compare the results of breech delivery when the babies weighed between 5 and 6 pounds with the results when the babies weighed more than 7 pounds. In these data, we have disregarded the frequency of fetal injury and morbidity, frac-
30
Randall, Baetz, and Brandy
July, l'!lil
\111 •
tures of fetal extremities, InJuries of the brachial plexus, and later evidence of cerebrospastic disease or mental retardation. This omission is due to our own conviction that such injury to the fetus usually occurs when the delivery is managed by a relatively inexperienced operator. In gathering these data, we have attempted to compare results that could hardly be altered by the experience and technical skill of the obstetrician. In the Buffalo General Hospital during the 10 years 1949 to 1958 there were a total of 20,162 deliveries including 4 79 breech presentations in which the baby weighed over 5 pounds at birth. This number of breech deliveries at or near term represented 2.4 per cent of the deliveries in this hospital during the 10 year period surveyed. In 90, or 18.8 per cent, of the 479 breech deliveries reviewed, the baby weighed between 5 and 6 pounds. In approximately one half of all breech presentations (234 of the 479 babies), the newborn infant weighed over 7 pounds. The frank breech was the most frequent type, and, somewhat to our surprise, the size of the fetus was found to have no appreciable effect on the relative frequency of a frank breech presentation. In 259 of the 479 cases (54.1 per cent of the breech deliveries), the fetus presented as a frank breech. Of 90 cases in which the baby weighed 5 to 6 pounds at birth, 50, or 55 per cent, involved a frank breech presentation. Of the 234 cases in which the baby weighed over 7 pounds at birth, 127, or 54.3 per cent, involved a frank breech presentation. Footling or compound presentation was also not more frequent among either the larger or the smaller babies. There seemed to be no concentration of factors increasing the risk to the fetus in either the smaller ( 5 to 6 pounds) or the larger (over 7 pounds) group, other than those factors which would be expected to be related to the birth of relatively large or relatively small babies. For this reason, we thought it reasonable not to attempt to "correct" our figures for such factors as premature rupture of the membranes, precipitate labor, or multiparity. The outcome was to some extent influenced
.f. <)IJ,t. & Gyn<:e.
by those secondary factors associated with fetal size. It is evident. for instance, that, when breech presentation persists, spontaneous premature rupture of the membranes is more likely. With the breech presenting, a relatively longer latent period between such premature spontaneom rupture of the membranes and the onset of labor can be expected, and this latent p<:>riod is likely to be longer when the babies are smaller. In 64 cases in which the baby weighed between 5 and 6 pounds, it was found that the time between premature rupture of the membranes and the onset of labor averaged 15.1 hours compared to an average of only 9.CJ hours in 195 cases of breech delivery following premature rupture of the membranes when the babies all weighed over 7 pounds. A relatively longer period of total time in the labor room, in the presence of a small baby, might be at least partially due to the relative unripeness of the cervix and unresponsiveness of the myometrium. Among our own cases, however, we did not find the correlation we had expected between the length of labor and the size of the baby. In the primigravidas, when the baby presenting by the breech weighed between 5 and 6 pounds, labor averaged 11.4 hours compared to 18.3 hours when the baby weighed more than 7 pounds. When the mother was a multipara and the baby weighed between 5 and 6 pounds, breech labors averaged 8.8 hours compared to 9.9 hours when the baby weighed more than 7 pounds. The second stage of labor in the primigravida averaged 57.3 minutes when the baby weighed between 5 and 6 pounds and averaged nearly twice that, or 191.5 minutes, when the baby weighed more than 7 pounds. When a multipara had a breech presentation, the second stage of labor averaged 32 minutes when the baby weighed 5 to 6 pounds and 38.6 minutes when the baby weighed over 7 pounds. Cesarean section was elected before the onset of labor in 1.2 per cent of the cases when the baby weighed between :) and 6 pounds and in 4.8 per cent of the cases when
Risks in breech delivery 31
Volume 82 Numht·r 1
the baby weighed over 7 pounds. Among the mothers of smaller babies, 2.5 per cent were delivered by cesarean section after there seemed to be no progress in labor, but when the babies weighed more than 7 pounds at birth 3.5 per cent of the mothers were delivered by cesarean section because labor did not progress. There was no evidence of a greater risk of prolapse of the cord with the smaller ( 5 to 6 pounds) babies than with the larger (over 7 pounds) babies. In 5 of the 12 cases in which prolapse of the cord became evident (or 40 per cent), this complication was first recognized during the second stage of labor. Breech delivery was completed "without difficulty" in 85 per cent of the cases when the baby weighed between 5 and 6 pounds, and with no difficulty in only 70 per cent of the cases when the baby weighed over 7 pounds. Greater difficulty with larger babies is evidenced also in the fact that Piper forceps were used in 12 per cent of the deliveries of the smaller babies and in 21 per cent of the cases when the baby weighed over 7 pounds at birth. It must be admitted, however, that the Piper forceps were at times regarded as a means of affording protection to the aftercoming head of an obviously small fetus, whereas the forceps were not likely to have been elected in the birth of the relatively larger babies for any such purely prophylactic consideration. Niswander and Patterson 4 have recently reviewed the records of 1,000 consecutive labors which were electively induced during the past 3 years in the Children's and Buffalo General Hospitals. Among the labors reviewed were 22 cases in which the persistence of a breech presentation had apparently not been recognized when the decision was made to induce labor. The outcome in these 22 cases in which labor was electively induced with the breech presenting has been the subject of much local interest. There were 2 babies in the 5 to 6 pound group. One had no difficulty. In the other the cord prolapsed and, although a cesarean section was performed promptly, the baby
did not survive. There were 8 babies in the 6 to 7 pound group. Seven had no difficulty, but one presented as a footling, the cervix dilated rapidly, delivery of the aftercoming head was considered difficult, and the child did not survive. There were 12 babies in the group weighing more than 7 pounds at birth; there was no difficulty with the delivery of any of the 12, and alt survived without complication. Among the cases of breech delivery managed at the Buffalo General Hospital between 1949 and 1958, smaller babies seem more frequently associated with fetai ioss. Among the 90 cases of breech delivery when the babies weighed 5 to 6 pounds, the gross loss was 6.66 per cent, correctable to a fetal mortality of 3.33 per cent. This loss among the smaller babies with breech presentation, seems high considering the fact that the corrected fetal mortality, when only babies weighing over 7 pounds were considered, was 1. 7 per cent in a total of 234 breech deliveries at term. It is evident that we may be maintaining a conviction upon the basis of two sets of rather meager data. When labor was electively induced in 22 cases of breech presentation, one of the 2 babies weighing between 5 and 6 pounds and one of the 8 babies weighing between 6 and 7 pounds died, while all of the 12 weighing more than 7 pounds survived without difficulty. In only 2 of those 22 babies with breech presentation was labor induced when the baby weighed under 6 pounds, but in one of the 2 the cord prolapsed and the fetus did not survive. Although this is only a single case, it nevertheless seems a good example of the fact that when the breech is presenting and labor begins when the baby is still small and before it is well down into the pelvis, accidents seem more likely to happen. Comment
Cases studied are but few, even with a review of breech deliveries in the Buffalo General Hospital during the past 10 years. Can we draw conclusions based on the fate of only 7 babies among the 324 breech de-
July, 1Y!>l
32 Randall, Baetz, and Brandy
liveries considered? What would have happened to our conviction if we had lost 2 instead of 3 among the 90 babies weighing between 5 and 6 pounds, and lost 5 instead of 4 among those weighing more than 7 pounds? Such a shift involving realignment of but one of the 7 fetal deaths would, of course, have reduced the deaths among the smaller babies by 33 per cent and increased the deaths among the larger babies by 25 per cent. The loss of 2 among 90 smaller babies would have meant a fetal mortality of 2.2 per cent for the 5 to 6 pound group, and the loss of 5 babies instead of 4 among the group weighing more than 7 pounds would have meant a fetal mortality of 2.1 per cent for the larger babies. This would seem to suggest that there will have to be more than a 14 per cent shift in the fetal loss from the smaller to the larger baby groups before we could provide data that would make efforts
REFERENCES
1. Baetz, R. W., and Randall, C. L.: New York J. Med. 48: 49, 1948. 2. Baetz, R. W.: New York J. Med. 55: 2627, 1955. 3. Baetz, R. W.: Unpublished annual reports to the Buffalo Obstetrical and Gynecological Society. 4. Niswander, K. R., Patterson, R. J, and Ran-
Am. j. Ob"t. & Gynec.
to assure delivery of relatively smaller babies seem advisable. Summary
From our data, a comparison of the difficulties experienced with breech deliveries when the babies are small ( 5 to 6 pounds) and those when the babies weigh more than 7 pounds, three conclusions may be reached: 1. With the smaller babies, there was no increased incidence of prolapse of the cord and no increased incidence of unfavorable footling presentations. 2. With the smaller babies, labor was less frequently difficult and less likely to terminate in cesarean section after a few hours of ineffectual contractions. 3. We can find no reason to believe, however, that we could reduce the frequency of the fatal complications of breech delivery by inducing labor when we think the baby will weigh between 5 and 6 pounds.
dall, C. L.: AM. J. OasT. & GYNEC. 79: 797, 1960. 5. Potter, Milton, G.: Proc. First American Gong. Obst. & Gynec. 1: 343, 1940. 6. Potter, Milton G., Ervin, Henry, and Brown. ]. Bruce: AM. J. OasT. & GYNEC. 49: 567, 1945. 7. Vartan, C. Keith: J. Obst. & Gynaec. Brit Emp. 52: 417, 1945.