The Risk Of Rupture Of The Uterus An Analysis Of 1086 Births After Previous Caesarean Section

Journal of Obstetrics and Gynaecology

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The risk of rupture of the uterus: an analysis of 1086 births after previous caesarean section W. Neuhaus, G. Bauerschmitz, U. Göhring, T. Schmidt To cite this article: W. Neuhaus, G. Bauerschmitz, U. Göhring, T. Schmidt (2001) The risk of rupture of the uterus: an analysis of 1086 births after previous caesarean section, Journal of Obstetrics and Gynaecology, 21:3, 232-235, DOI: 10.1080/01443610120046297 To link to this article: https://doi.org/10.1080/01443610120046297

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Journal of Obstetrics and Gynaecology (2001) Vol. 21, No. 3, 232– 235

OBSTETRICS

The risk of rupture of the uterus: an analysis of 1086 births after previous caesarean section W. NEUHAUS, G. BAUERSCHMITZ, U. GÖHRING and T. SCHMIDT Department of Gynaecology and Obstetrics, University of Cologne, Germany

Summary In the work presented here, obstetric management after a previous caesarean section was studied in a large patient group at the University Department of Gynecology and Obstetrics in Cologne from 1979 to 1995. Particular attention was given to the feared complication of uterine rupture. From a total of 15 166 deliveries, 1086 of the births had been preceded by one or more caesarean sections. These 1086 births formed the basis for the present study. Vaginal delivery was attempted in 44·5% of patients and was successful in 86% of those cases. Where there had been only one previous caesarean section, the percentage shifted in favor of vaginal delivery. All patients with more than two previous caesarean sections were delivered by elective caesarean section. The feared complication of rupture of the uterus occurred in four cases, for which case reports are presented. In view of such cases, signs of imminent uterus rupture often constitute an indication for elective (11·5%) or emergency resectioning (31·9%). No relationship was found between fetal outcome and mode of delivery. This retrospective study confirms the general recommendation and safety of vaginal delivery after a previous caesarean section as long as risks are minimised by a readiness to proceed with a repeat caesarean when signs of imminent rupture of the uterus arise.

Introduction In the 1970s the proportion of deliveries carried out by caesarean section rose and postoperative complications became rarer, rendering the operation less dangerous. Elective sections, for maternal as much as for fetal indications, won increasing acceptance. As a result of the increased rate of delivery by caesarean section the problem of how to manage births after a previous caesarean also presented itself more frequently. In 1970 the ratio of births following a previous caesarean section at the University Department of Gynecology and Obstetrics in Cologne was just one in 46 (Marx, 1986), but between 1979 and 1995 the question of what mode of delivery to follow in such cases arose, on average, at every 14th birth. Contrary to the dogma ‘Once a Caesarean, always a Caesarean’ postulated by Cragin in 1916, accepted practice today is to attempt vaginal delivery in almost every pregnancy after a previous caesarean, as long as the indication for the first section has not persisted and no new indication has arisen. The anamnestic note ‘previous Caesarean section’ is no longer regarded as a compelling indication for a further section. The incidence of complications arising during pregnancy or birth is higher after a previous caesarean

section, and for a long time the risk of uterine rupture dissuaded obstetricians from attempting vaginal delivery. Even with today’s low rate of uterine rupture, this complication is still taken extremely seriously owing to its dramatic clinical consequences. The aim of the present study was to review obstetric management after previous delivery by caesarean section in one particular institution, paying special attention to the complication of uterine rupture. Patients and methods In the period from 1 January 1979 to 30 September 1995 a total of 15166 births took place at the University Department of Obstetrics and Gynecology in Cologne. There had been one or more previous deliveries by caesarean section in 1086 of these cases, which corresponds to a rate of 7·16% or every 14th birth. These 1086 births formed the patient group for the present study. The data were obtained from the department’s own data centre and supplemented by information from the patients’ records. The main points compared in the analysis were: · · · · ·

mode of delivery, indications for operative delivery, obstetric management of vaginal delivery, fetal outcome, and the complication of uterine rupture presentations).

(case

Results Mode of delivery Of 1086 births after previous caesarean section, 369 women were delivered spontaneously, 47 vaginally with operative intervention, 67 by emergency casarean sections and 603 by an elective caesarean section. Thus, a vaginal delivery was attempted in 44·5% of patients, and was brought to a successful conclusion in 86% of these cases (Figure 1). Where there had been only one previous caesarean (N=954) the results shifted in favour of vaginal delivery, which was then the predominant mode of delivery, being used in more than 50% of those cases (Figure 2). Of the 112 births after a repeat caesarean section five women (4·5%) were delivered spontaneously, two (1.8%) vaginally with operative intervention, seven

Correspondence to: Dr. W. Neuhaus, Department of Obstetrics and Gynaecology, St Josefs hospital Uerdingen, Post fach 266, 47813 Krefeld, Germany. ISSN 0144– 3615 print/ISSN 1364– 6893 online/01/030232– 04 ã Taylor & Francis Limited, 2001 DOI: 10.1080/0144 36101200462 97

Risk of rupture of the uterus

Spontaneous (34.0%) Primary (elective) caesarean . section (55 5%) Vaginal/operative (4.3%) Secondary (emergency) caesarean section (6.2%)

Figure 1. Mode of delivery after caesarean section.

(6·2%) by emergency caesarean section and 98 (87·5%) by elective caesarean section. A total of 20 patients with more than two previous caesarean sections were delivered by an elective caesarean section. Indications for operative delivery The most common indication for elective repeat caesarean section (27·3%) was the anamnestic note ‘previous Caesarean section’, reflecting a desire to minimise risks. In a quarter of these cases the main decisive factor was the pregnant woman’s request for a repeat abdominal delivery. Premature birth was the second most frequent indication for caesarean section at 14·8%. Malpositions, non-engagement of the fetal head and signs of imminent uterine rupture were the main indications in 11·5% cases each, followed by rarer indications or combinations of reasons. The most important indication for repeat section (40·3%) was failure to progress in labour and fetal distress. Management of vaginal delivery With regard to the feared complication of uterine rupture the current literature suggests that the following obstetric measures are usually contraindicated. Inducing labour with prostaglandins, administration of oxytocic drugs during birth and epidural anaesthesia. In the present patient group, in 15·5% of the cases labour was induced with prostaglandins. The most common indication for this was that the birth was overdue. In the course of delivery an infusion with oxytocin was administered to stimulate contractions in 35·6% of cases. The main

Spontaneous (40.2%) Primary caesarean section (48.3%)

Vaginal/operative (5.0%) Secondary caesarean section (6.5%)

Figure 2. Mode of delivery after one caesarean section.

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indication for that treatment was failure to progress in labour. Epidural anaesthesia to alleviate pain during birth was given to 9·8% of patients undergoing vaginal delivery. Fetal outcome In the assessment of fetal outcome, it should be remembered that, in any patient group taken from a university department of obstetrics, the proportion of high-risk cases will be higher than normal. Thus, the perinatal mortality was relatively high, at 24/1000, and several stillbirths could be attributed to premature birth or severe malformations. There was no relation to the mode of delivery selected in any of these cases; nor, with regard to the 5-minute Apgar score, were any significant differences found in relation to the mode of delivery. The average umbilical arterial pH value was 7·3 to 7·4 for elective repeat sections and between 7·2 and 7·3 for vaginal deliveries. Postpartum pre-acidosis and acidosis, with pH values of below 7·2 or 7·1, respectively, occurred most frequently after vaginal delivery, especially with operative intervention, and after emergency caesarean section, which in this context could be attributed to ‘imminent fetal asphyxia.’ The special situation of vaginal delivery after previous caesarean section was not related in any way to any deviation from the norm with regard to fetal outcome. The complication of uterine rupture (case presentations) Rupture of the uterus was recorded in four cases among the 1086 births studied between 1979 and 1995, corresponding to a frequency of 0·37%. These four cases are presented here as brief case histories. (1) 1981: primary Caesarean section due to breech presentation. With the next pregnancy the following year, we aimed for vaginal delivery. After spontaneous onset of labour 6 days after the expected date of birth, severe abdominal pains suddenly arose during a CTG examination in the early dilation period. Fetal protrusion above the symphysis was felt together with peritoneal symptoms of an acute abdomen. Immediate laparotomy revealed a rupture of the old scar at the level of the isthmus. The child was lying free in the abdominal cavity, the placenta had separated and was lying in the gaping tear. The child was delivered alive and soon recovered. The placenta was removed completely and the old scar was sutured in the standard way. Mother and child recovered without any further complications. (2) 1980: primary elective caesarean section due to breech presentation. 1987: there was a spontaneous and rapid birth. Routine digital examination of the scar revealed a 2 cm-long dehiscence at the right end of the scar area. Clinical symptoms were restricted to sensitivity to pressure above the symphysis. A relaparotomy was carried out with resuturing of the concealed rupture. (3) After three previous caesarean sections, in 1992 hospitalization of the 22-year-old patient was indicated in the 22/23rd week of pregnancy on account of vaginal bleeding with formation of a

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60 50 40 30 20 10 0 79

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Figure 3. Mode of delivery 1979–1995. (spontaneous ¨ ; vaginal/operative Elective caesarean section ).

haematoma in the region of the internal os. Persistent vaginal bleeding with falling haemaglobin and growth of the haematoma despite tocolytic treatment suggested rupture of the scar. Rupture in the region of the old scar was confirmed at laparotomy. A late abortion was inevitable and given the threat to the mother’s life, the uterus was emptied and then removed by hysterectomy. (4) 1987: caesarean section on account of moderate disproportion. 1994: After attempted vaginal delivery, emergency caesarean section was carried out due to imminent fetal asphyxia, indicated by prepathological CTG alterations. Intraoperatively the lower section of the uterus was found to be extremely thin, with a bleeding partial uterine rupture spreading into the surrounding tissue on the left side. Standard resuturing was carried out to preserve the uterus. Mother and child survived unharmed. Discussion The frequency of the various modes of delivery after previous caesarean section were reviewed using data from the literature. All the studies listed were carried out within the period 1987–1994 and are therefore comparable (Table I). In interpreting the findings of the present study it should be taken into consideration that a group of births taken from a period of more than 15 years cannot be homogeneous. As expected, over the years a moderate decline is seen in the tendency to carry out elective repeat sections from 66·7% in 1979 to 52·9% in 1995 in favour of attempted spontaneous birth (24·5% 1979, 37·3% 1995). Most striking, however, is the immediate rise in the rate of caesarean sections after the cases of uterine rupture described in 1982, 1987 and 1992 (Figure 3). These events, traumatic experiences for any department of obstetrics, undoubtedly affected subsequent diagnosis and choice of procedure. The high success rate of 86% for attempted vaginal delivery (trial of Scar) ending in vaginal birth, together with the low rate of uterine rupture (0·37%), can be attributed to a relatively defensive attitude towards indications for elective & emergency repeat caesareans. The lower rate of uterine ruptures is counterbalanced by a high quota of elective and especially emergency

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; Emergency caesarean section s ;

resectionings on account of ‘imminent uterine rupture’ signified by isolated scar pain unrelated to contractions or on account of failure to progress in labour or ‘imminent fetal asphyxia’ as possible secondary signs of imminent uterine rupture. In the current literature attempted vaginal delivery {trial of scar} is the preferred approach and considered a tenable risk in almost all cases. Exceptions are births after a previous longitudinal upper segment section (classical section) after previous uterine rupture, and—although opinions differ here—after multiple deliveries by caesarean section (Lai Sidek, 1993; Marx, 1986). Pregnant women requesting a repeat section are, in some cases, advised to consider the lack of any indication for this and to base their decision on a extensive preoperative explanation of the real risks involved. The rates of uterine rupture were 0·03–0.1% for an unselected patient group, compared with 0·2– 1·5% for the group with a previous caesarean section. The risk increased after two or more previous caesareans to over 2%, with further possible factors, such as high-grade multiparity, short intervals of less than a year between pregnancies and advanced maternal age, increasing the predisposition to rupture. On the other hand, fetal macrosomia, with birth weights of more than 4000 g, does not increase the risk any more than would a twin pregnancy, as long as other Table I. Studies carried out between 1987 and 1994 Study

Molloy et al., 19 87 Videla et al., 19 95 Behrens et al., 1994 Farmer et al., 1991 Phelan et al., 1987 Lai et al., 1993 van der Walt et al., 1994 UFK Köln Paterson and Saunders, 1991 Coltart et al., 1990 Rosen et al., 19 91 Chattopadhyay et al., 1988 Flamm et al., 1990 Yetman and Nalan 1989 Holland et al., 199 2

Aimed for vaginal Percentage delivery successful 74·4 % 7 2·0% 7 3·8% 5 4·5% 5 3·5% 4 9·4% 4 4·9% 44 ·5 % 4 4·5% 4 3·6% 4 0·4% 3 9·8% 2 8·4% 2 5·6% 12 ·9 %

90 ·8 % 88 ·0 % 84 ·9 % 79 ·2 % 81 ·0 % 65 ·0 % 56 ·7 % 86 ·0% 71 ·0 % 79 ·0 % 73 ·9 % 50 ·9% 75 ·0% 61 ·2% 71 ·0 %

Risk of rupture of the uterus

sets of risk factors are absent. For obstetric management of vaginal births today, induction with prostaglandins for strictly defined indications, infusion of oxytocin during labor, administration of analgesics and epidural anaesthesia are considered justified. The conservative approach is not even contraindicated by a breech presentation. Sonographic checking of the scar, the measuring of intrauterine pressure and a ‘prophylactic’ vaginal-operative delivery are not recommended. Routine postpartum checking of the sectioning scar by feel and, above all, recommended sterilisation after more than two caesareans are both unnecessary precautions. The obstetric institution should, of course, be in a position to carry out an emergency caesarean section. Statements concerning obstetric management after previous caesarean section can only be based on retrospective studies and are therefore meaningful only to a limited extent. The scientifically sounder information provided by prospective randomised studies is unattainable in relation to this clinical problem. The causality of rare complications such as uterine rupture can scarcely be established even in large patient groups such as that presented here, when one considers that among a total of 15 000 births, 1086 of which followed previous deliveries by caesarean section, only four cases of uterine rupture were recorded. One of these four cases was first detected through the once-routine checking of the vaginal palpation and would today have probably gone undiscovered without any consequences. In a second patient, the concealed rupture was also incidentally detected at the time of a repeat caesarean, performed to avoid imminent fetal asphyxia. In a third case spontaneous rupture, unrelated to labour, occurred long before the expected date of birth in a patient who had had three previous caesareans. This led to a late abortion and loss of the uterus. The full drama of uterine rupture during birth was manifested in only one case, and here damage to the mother and child was averted successfully through adequate emergency measures. In summary, this retrospective analysis of a large patient group extending over 15 years confirms the basic recommendation of vaginal delivery after previous caesarean section as long as risks are minimised by a readiness to proceed with emergency section in the event of a prolonged labour, prepathological CTGdevelopments or isolated scar pain, any of which could signify ‘imminent uterine rupture’. The responsible obstetric department should be familiar with procedures required for obstetric management of a high-risk

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birth and be in a position to carry out an ‘emergency caesarean section’. References

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