- Email: [email protected]
Maternal and neonatal outcomes after uterine rupture in labor
Maternal and neonatal outcomes after uterine rupture in labor O.W. Stephanie Yap, MD, Eleanore S. Kim, MD, and Russell K. Laros, Jr, MD San Francisco, California OBJECTIVE: There is significant controversy about the risks related to attempted vaginal birth after cesarean and the implications for informed consent of the patient. Recent data suggest that women who deliver in hospitals with high attempted vaginal birth after cesarean rates are more likely to experience successful vaginal birth after cesarean, as well as uterine ruptures. We conducted a study to evaluate maternal and neonatal morbidity and mortality after uterine rupture at a tertiary care center. STUDY DESIGN: We performed a retrospective chart review of cases of uterine rupture from 1976 to 1998. All women who had a history of uterine rupture were identified with International Classification of Diseases, Ninth Revision, identifiers with hospital discharge data cross-referenced with a separate obstetric database. We abstracted demographic information, fetal heart rate patterns, maternal pain and bleeding patterns, umbilical cord gas values, and Apgar scores from the medical record. Outcome variables were uterine rupture events and major and minor maternal and neonatal complications. RESULTS: During the study period there were 38,027 deliveries. The attempted vaginal birth after cesarean rate was 61.3%, of which 65.3% were successful. We identified 21 cases of uterine rupture or scar dehiscence. Seventeen women had prior cesarean deliveries (10 with primary low transverse cesarean delivery, 3 with unknown scars, 1 with classic cesarean delivery, 2 with two prior cesarean deliveries, and 1 with four prior cesarean deliveries). Of the 4 women who had no history of previous uterine surgery, one had a bicornuate uterus whereas the others had no factors increasing the risk for uterine rupture. We confirmed uterine rupture and scar dehiscence in 19 women. Specific details were not available for 2 patients. Uterine rupture or scar dehiscence was clinically suspected in 16 women with 3 cases identified at delivery or after delivery. Sixteen women had symptoms of increased abdominal pain, vaginal bleeding, or altered hemodynamic status. There were 2 patients who required hysterectomies and 3 women who received blood transfusions; there were no maternal deaths related to uterine rupture. The fetal heart rate pattern in 13 cases showed bradycardia and repetitive variable or late decelerations. Thirteen neonates had umbilical artery pH >7.0. Two cases of fetal or neonatal death occurred, one in a 23-week-old fetus whose mother had presented to an outlying hospital and the second in a 25-week-old fetus with Potter’s syndrome. All live-born infants were without evidence of neurologic abnormalities at the time of discharge. CONCLUSION: Our data confirm the relatively small risk of uterine rupture during vaginal birth after cesarean that has been demonstrated in previous studies. In an institution that has in-house obstetric, anesthesia, and surgical staff in which close monitoring of fetal and maternal well-being is available, uterine rupture does not result in major maternal morbidity and mortality or in neonatal mortality. (Am J Obstet Gynecol 2001;184:1576-81.)
Key words: Maternal and fetal or neonatal morbidity and mortality, uterine rupture or dehiscence, vaginal birth after cesarean, tertiary care center
Controversy continues over the management of labor after a previous cesarean delivery. Neither a repeat cesarean delivery nor a trial of labor is without risk. Various authorities have advocated a trial of labor after a previous cesarean delivery and numerous studies have identified risk factors associated with uterine rupture. Although it is a rare event, uterine rupture has potentially catastrophic From the Department of Obstetrics, Gynecology and Reproductive Sciences, University of California. Poster presentation, presented at the Sixty-seventh Annual Meeting of the Pacific Coast Obstetrical and Gynecological Society, Kamuela, Hawaii, November 14-19, 2000. Reprints not available from the authors. Copyright © 2001 by Mosby, Inc. 0002-9378/2001 $35.00 + 0 6/6/114855 doi:10.1067/mob.2001.114855
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consequences, and many studies have indicated the relative safety of labor after previous cesarean delivery in carefully selected and counseled patients. At issue are the morbidity and mortality associated with the trial of labor attempt after a cesarean delivery for these women and their babies. The risk of major maternal complications has been reported to be almost twice as likely in women who underwent a trial of labor than in women who chose an elective repeat cesarean.1 The same study also corroborated other data from Miller et al2 that the rates of major and minor complications were elevated and, in fact, were highest in women who elected to have a repeat cesarean delivery and whose history included 3 or more previous deliveries.1 A recent population-based study by Gregory et al3 in a population of women with his-
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Fig 1. Study population.
tories of cesarean deliveries disclosed an unadjusted relative risk for uterine rupture of 1.88 in women who attempted vaginal birth after cesarean (VBAC) with an attributable fraction of 34% compared with women not undergoing labor. The overall uterine rupture rate for women attempting a trial of labor was 0.43%. Further analysis of outcomes by type of delivery hospital showed that women delivering in hospitals with high attempted VBAC rates were more likely to experience successful VBAC than were women delivering in hospitals with low attempted VBAC rates (relative risk, 1.17); women delivering in hospitals with low attempted VBAC rates were also shown to have a higher risk of uterine rupture (relative risk, 1.56).3 This retrospective review was undertaken to examine maternal and perinatal morbidity and mortality outcomes after uterine rupture or scar dehiscence. We conducted this study to test the hypothesis that a trial of labor after cesarean delivery, conducted in an appropriate environment, is safe for mother and child. Material and methods We performed a retrospective chart review of cases of uterine rupture from 1976 to 1998 at the University of California, San Francisco Moffett-Long Hospital. International Classification of Diseases, Ninth Revision, codes for uterine rupture were used to identify patients from hospital medical records and discharge data. The cases identified were then cross-referenced with a separate obstetric database to obtain demographic information, fetal heart rate patterns, umbilical cord gas values, Apgar scores, and neonatal intensive care unit admission data. The primary outcome of interest was uterine rupture. For the purposes of this study, uterine rupture was defined as any disruption of the uterine wall associated with
Table I. Demographics and obstetric history of women with uterine rupture Maternal age (y) Parity 0 1 2–4 ≥5 Birth weight (g) <400 g >4000 g History of cesarean delivery All cases 1 prior cesarean 2 prior cesareans 3 prior cesareans 4 prior cesareans Unknown scar Classical Average length of stay (d) Vaginal delivery (d) Abdominal delivery (d)
29.5 4 (19%) 10 (47.6%) 6 (28.6%) 1 (4.8%) 2978 2 (10.5%) 2 (10.5%) 17 (81%) 10 (58.8%) 2 (11.7%) 0 1 (5.9%) 3 (17.6%) 1 (5.9%) 5 5 5
maternal symptoms or fetal heart rate abnormalities that required surgical intervention to deliver the fetus, repair the uterine wall defect, or perform a hysterectomy. Asymptomatic uterine dehiscence not requiring clinical or surgical intervention was not reported. Twenty-one cases of uterine rupture were identified. Medical record chart review was completed on 19 cases to collect information regarding labor abnormalities, oxytocin augmentation, use of invasive fetal or uterine monitoring, maternal symptoms, anesthesia use, transfusion, infection rates, length of hospital stay, and presence or absence of meconium at the time of delivery. Medical records were not available for two cases; however, data abstracted at the time of delivery were available in the departmental database.
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Table II. Characteristics of study women Case
Age (y)
Obstetric history
Surgical therapy
1 2 3 4 5 6 7 8 9
30 23 26 32 30 35 36 21 36
Gravida 3, para 1, 1 abortion, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 emergent low transverse cesarean Gravida 6, para 2, 1 low transverse cesarean Gravida 2, para 0, 1 abortion Gravida 2, para 0, 1 abortion Gravida 7, para 4, 1 cesarean, unknown scar
Repeat low transverse cesarean Repeat low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Primary low transverse cesarean Emergent low transverse cesarean Repeat low transverse cesarean
10
23
Gravida 6, para 4, 1 classical cesarean
Hysterectomy
11 12
33 31
Gravida 5, para 4, 4 cesareans Gravida 4, para 2, 1 cesarean, unknown scar
13 14
30 17
Gravida 2, para 1, 1 cesarean, unknown scar Gravida 2, para 0, 1 abortion
Emergent low transverse cesarean Exploratory laparotomy, repair after forceps-assisted vaginal delivery Hysterectomy Exploratory laparotomy, repair after vaginal delivery
15 16
38 28
17
39
18 19
21 28
20 21
26 37
Gravida 1, para 0 Gravida 6, para 3, 1 normal spontaneous vaginal delivery, 2 cesareans, unknown scar Gravida 6, para 5, 3 normal spontaneous vaginal deliveries, 2 low transverse cesareans Gravida 4, para 1, 1 cesarean, unknown scar Gravida 3, para 1, 1 therapeutic miscarriage or abortion, 1 cesarean, unknown scar Gravida 2, para 1, 1 low transverse cesarean Gravida 3, para 1, 1 abortion, 1 low transverse cesarean
Primary low transverse cesarean Emergent low transverse cesarean Repeat low transverse cesarean Repeat low transverse cesarean Repeat low transverse cesarean Exploratory laparotomy, repair Exploratory laparotomy, repair after forceps-assisted vaginal delivery
*Peripartum endomyometritis. †Chorioamnionitis.
Table III. Fetal and neonatal characteristics
Gestational Case age (wk) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
41 38 41 39 40 39 41 39 37 33 30 39 39 23 38 39 41 41 41 25 40
Abnormal fetal heart rate tracings
Umbilical cord artery pH
Neonatal intensive care unit admission
Newborn intubation
No. of days on ventilator
Newborn hospital stay (d)
Late-shaped deceleration, bradycardia No Terminal bradycardia Terminal bradycardia; multiple congenital anomalies Terminal bradycardia Repetitive variable deceleration No Terminal bradycardia Yes No Bradycardia Repetitive variable deceleration Late-shaped deceleration Death before labor Late-shaped deceleration, variable deceleration Repetitive variable deceleration Late-shaped deceleration Unknown Bradycardia Nonviable with anomalies No
7.20 — 7.13 6.80 7.05 7.22 7.33 7.14 6.92 7.19 6.72 7.09 7.14 — 7.24 — 7.05 7.17 6.94 — 7.03
No No Yes Yes Yes No No No Yes Yes Yes No Yes — No No Yes No Yes — No
No No No Yes Yes No No No Yes Yes Yes — Yes — No Yes Yes No Yes — No
0 0 <1 <1 0 0 0 0 3 — 22 0 0 — 0 0 <1 0 0 — 0
2 — 6 13 6 3 2 3 14 16 34 2 3 — 3 4 7 4 4 — 4
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Surgical anesthesia Epidural General endotracheal General endotracheal General endotracheal General endotracheal General endotracheal Epidural General endotracheal Epidural, general endotracheal General endotracheal
Transfusion
Hospital stay (d)
No No No No No No No No Yes
4 4 4 5 8* 4 5 4 6
4 units of packed red blood cells No No
6
5 5
Epidural Epidural
No 2 units of packed red blood cells No No
Epidural
No
4†
Epidural Epidural
No No
4 6
Epidural Epidural
No 1 unit of packed red blood cells
7 6
General endotracheal Epidural Epidural General endotracheal
5 4
4 5
Results The patient population at the University of California, San Francisco Moffett-Long Hospital is primarily composed of a group of private practice patients from middle to upper socioeconomic class and a smaller group of staff patients who are from a lower socioeconomic class. There were 38,027 deliveries at the University of California, San Francisco Moffett-Long Hospital from 1976 to 1998. Fig 1 summarizes the breakdown of these deliveries into those women who were with or without a history of cesarean delivery. Women with histories of cesarean delivery represented 8.7% (3319) of all deliveries. The attempted VBAC rate was 61.3%, of which 65.3% were successful. Twenty-one cases of uterine rupture were identified, resulting in a uterine rupture rate of 0.06%. Two cases were incidental findings; one diagnosis was made at the time of cesarean for failure to progress (case 7), and the other diagnosis was made at manual removal of placenta (case 12). Demographic characteristics, birth weight, and history of cesarean are noted in Table I. Seventeen women with uterine rupture had a history of the following cesarean deliveries: 10 with previous low-transverse uterine incisions, 3 with unknown scars, 1 with a history of classic uterine incision, and 3 with two or more previous ce-
sarean deliveries. Uterine rupture occurred in 4 women who did not have a history of uterine surgery or cesarean delivery. No cases of uterine rupture were identified after elective repeat cesarean delivery. Maternal and neonatal characteristics of the 21 cases of uterine rupture are outlined in Tables II and III. Eighteen were delivered by cesarean after a trial of labor; 3 were delivered vaginally, either spontaneously or assisted. The fetus of one woman (case 10) who presented for labor evaluation was found to be profoundly bradycardic and was promptly taken for an emergent cesarean delivery. The patient had a history of cocaine use and also had a positive drug screening result for cocaine at the time of delivery. Three cases of uterine rupture were identified at the time of delivery or post partum. Two cases of uterine rupture occurred in patients who underwent forceps-assisted vaginal delivery. One case of uterine rupture occurred after spontaneous vaginal delivery in a bicornuate uterus. Hysterectomy was performed in 2 patients; both had a history of cesarean delivery. One woman had a history of a classic cesarean delivery and subsequent vaginal delivery of a 33-week-old fetus with a postpartum diagnosis of a 7-cm rupture in the anterior uterine wall. The second woman had a 9-cm uterine rupture with development of late decelerations and fetal bradycardia. The exact reasons for choosing hysterectomy rather than repair of the rupture were not clarified by the medical record. Information regarding the course of labor was available for the majority of women. Eight patients presented to the hospital in spontaneous labor. A total of 15 women had labor induced or augmented; of these 15 women, 7 had labor induced and 8 had labor augmented with prostaglandin gel or oxytocin. Uterine contractions were monitored with an intrauterine pressure catheter in 8 women. Uterine rupture was suspected clinically in 16 women before delivery from a combination of altered fetal heart rate tracings, maternal pain, increased bleeding, or altered hemodynamic status. Two women presented with increased maternal bleeding (cases 11 and 21), and 5 women reported increased pain (cases 2, 6, 10, 11, and 14). Of the remaining 5 cases of uterine rupture that were not suspected, 2 were asymptomatic, and 3 were identified at the time of delivery or immediately post partum. The decision regarding incision time was examined whenever possible; it was found to be ≤26 minutes. Operative and delivery reports were reviewed for all patients, and there was no report of bladder or rectal lacerations. Three women received blood transfusions; of these 3 women, only 1 had presented with increased bleeding (case 21). Ten women had epidural anesthesia and 8 women had general anesthesia for delivery or laparotomy. There were no maternal deaths in any of the patients who experienced uterine rupture.
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Four women who experienced uterine rupture had no history of uterine surgery or cesarean. Only one of these women had any of the risk factors associated with uterine rupture. This was the patient identified with a bicornuate uterus (case 14). An association of an increased risk for infection, such as chorioamnionitis, endomyometritis, or abdominal wound infection, was unsupported in our study. Chorioamnionitis developed in 2 women, with one case progressing to endomyometritis. None of the women had wound infections. The average length of stay for women who experienced uterine rupture and who delivered by repeat cesarean was not different than that of women who delivered vaginally. The average length of stay for both groups was 5 days. Details on fetal heart rate tracings were available for review in 18 patients only (Table III). Fourteen showed evidence of fetal heart rate abnormalities such as repetitive variable decelerations, late decelerations, bradycardia, or a combination of the three. Cord blood gas data were available for 17 infants. Thirteen had umbilical artery pH >7.0. Four infants had cord blood pH <7.0. Information on Apgar scores was available for 18 infants. Thirteen had 5-minute Apgar scores >6. Two cases of fetal or neonatal death occurred; one was in a 23-week-old fetus whose mother had presented to an outlying hospital (case 14), and the second was in a 25-week-old fetus with Potter’s syndrome (case 20). Four infants had evidence of meconium-stained amniotic fluid at the time of delivery. Nine infants were admitted to the neonatal intensive care unit; 5 of these infants required respiratory support for <24 hours, 1 required respiratory support for 3 days, and another infant who was delivered at 30 weeks’ gestation remained intubated for 22 days. All live-born infants were discharged without evidence of neurologic abnormalities. Average length of nursery stay for the newborns was 7.5 days. Four infants had prolonged hospital courses between 13 and 34 days (Table III; cases 4, 9, 10, and 11). All were delivered at <37 weeks’ gestation, and 3 had umbilical artery pH <7.0 at birth (cases 4, 9, and 11). Two of these infants weighed <2500 g (cases 10 and 11), and 1 had been diagnosed prenatally with a fetal anomaly (case 4). Comment In this study we were able to confirm the relatively small risk of uterine rupture after VBAC. Our attempted VBAC rate was 61.3%, which places our institution in the category of hospitals with a high attempted VBAC rate. Trial of labor after previous cesarean delivery had a 65.3% success rate, with an overall risk of uterine rupture of 0.06%. Specifically, women who had a history of cesarean deliveries had an 0.8% uterine rupture incidence compared with 0.01% in women who did not have a history of cesarean deliveries. In the literature to date, the overall risk of uterine rupture for women undergo-
June 2001 Am J Obstet Gynecol
ing a trial of labor after a cesarean delivery has been reported to be between 0.2 and 1.0%.1, 2, 4-7 Gregory et al3 reported an overall uterine rupture rate of 0.088% in hospitals with high VBAC rates compared with an overall uterine rupture rate of 0.056% in hospitals with low VBAC rates. The most critical issue regarding a trial of labor after a previous cesarean delivery is that of a catastrophic complication, such as uterine rupture with serious maternal and perinatal morbidity or death. McMahon et al1 reported a 1.8-fold increased risk of major complications for women who elected to have a trial of labor compared with the risk for those who chose a repeat cesarean delivery and who previously had 2 or fewer successful vaginal deliveries. The greatest risk occurred in women for whom the trial of labor was unsuccessful.1 Rageth et al8 disclosed an elevated risk of 2 of uterine rupture for patients who had a history of cesarean delivery and were undergoing a trial of labor versus elective repeat cesarean. Nevertheless, all other maternal risks, such as peripartum hysterectomy, thromboembolic complications, and febrile complications, were lower. Our findings are consistent with this report, with 2 patients having to undergo peripartum hysterectomy, 2 patients who experienced febrile events, and 3 patients who required blood transfusions. Previous larger studies have demonstrated complications that were predominantly minor but that were not inconsequential.7, 9 However, one also has to remember that an elective repeat cesarean delivery does not completely eliminate the risk of scar dehiscence or uterine rupture. Numerous studies have been conducted to identify risk factors that predispose patients to uterine rupture. Uterotonic agents have been associated with an increased risk of uterine rupture in labor.7, 8, 10 Rageth et al8 reported a 24% incidence of labor induction among women who experienced uterine rupture compared with a 14% incidence among women who did not experience uterine rupture. In our patient population 71.4% of women who experienced uterine rupture had labor either induced or augmented with prostaglandin E2 or oxytocin. The association of oxytocin induction, oxytocin augmentation, and use of prostaglandin E2 was recently examined by Zelop et al.11 Induction of labor with oxytocin appeared to confer a 4.6-fold increased risk of uterine rupture compared with no oxytocin use among women with one previous cesarean delivery who attempted a trial of labor. In this analysis we describe a case of uterine rupture in a woman with a bicornuate uterus without a prior delivery. A review of the literature showed a high cesarean delivery rate between 27.5% and 63% in patients with uterine anomalies.12-14 We did not find reports on uterine rupture events in these women. There is one case report of a catastrophic uterine rupture event that occurred in a woman with a unicornuate uterus who attempted VBAC.16 Current practice guidelines do not universally
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exclude women with müllerian duct anomalies from attempting VBAC, but recent data show a high rate of uterine rupture (8%) in these women even though there is a high rate of successful VBAC.17 Increased rates of suspected and proven neonatal sepsis necessitating antibiotic interventions and prolonging hospitalizations have been cited as complications of a trial of labor after a previous cesarean delivery. A recent study demonstrated that the increased rates of suspected and proven sepsis were limited to infants delivered by cesarean after a failed trial of labor.12 In fact, they reported that neonatal outcomes after a successful trial of labor were similar to neonatal outcomes after vaginal births and that infants delivered by elective repeat cesarean delivery actually were at increased risk of developing respiratory problems. The perinatal outcomes for our infants were reassuring. After we excluded fetal deaths occurring before labor and in fetuses with lethal congenital anomalies, the perinatal mortality rate was 0%. Our results do not support an association between an increased perinatal death rate and a trial of labor. There was a prolonged hospital course for 4 of the newborns from 13 to 34 days, and at time of discharge all infants were without evidence of neurologic abnormalities or complications. A potential limitation of this study is the relatively small number of uterine rupture events. However, this study comprehensively reflects the VBAC experience at a tertiary care hospital with a consistent style of management over a 22-year period. We believe that our experience accurately portrays the risks of VBAC attempts for mother and child in an optimal practice setting. Another bias is that not all uteri were palpated after birth, and therefore some asymptomatic scar dehiscences or windows may have gone undetected. However, the clinical significance of these asymptomatic defects, which do not require intervention, remains to be seen. For a woman who has had a previous cesarean delivery, a choice must be made between a trial of labor and an elective repeat cesarean delivery. Our results have important implications for counseling these patients. We have demonstrated minimal major morbidities for mother and child when we have been able to recognize uterine scar dehiscence or rupture events and respond expediently. Therefore the hospital setting in which these patients are managed bears further discussion. The ability to recognize the various signs that portend a possible rupture event, such as fetal distress, maternal pain, or hypoten-
sion, and then to address the situation immediately is critical to a good outcome. In this context, we suggest that a trial of labor after a previous cesarean delivery is safe for patients who are managed in a hospital with the capacity to conduct increased surveillance and to accomplish emergent cesarean deliveries and exploratory laparotomies, if necessary. REFERENCES
1. McMahon MJ, Luther ER, Bowes WA, Olshan AF. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med 1996;335:689-95. 2. Miller DA, Diaz FG, Paul RH. Vaginal birth after cesarean: a 10year experience. Obstet Gynecol 1994;84:255-8. 3. Gregory KD, Kors LM, Cane P, Platt LD, Kahn K. Vaginal birth after cesarean and uterine rupture rates in California. Obstet Gynecol 1999;94:985-9. 4. Flamm BL, Newman LA, Thomas SJ, Fallon D, Yoshida MM. Vaginal birth after cesarean delivery: results of a 5-year multicenter collaborative study. Obstet Gynecol 1990;76:750-4. 5. Leung AS, Leung EK, Paul RH. Uterine rupture after previous cesarean delivery: maternal and fetal consequences. Am J Obstet Gynecol 1993;169:945-50. 6. Phelan JP, Clark SL, Diaz F, Paul RH. Vaginal birth after cesarean. Am J Obstet Gynecol 1987;157:1510-5. 7. Rosen MG, Dickinson JC, Westhoff CL. Vaginal birth after cesarean: a meta-analysis of morbidity and mortality. Obstet Gynecol 1991;77:465-70. 8. Rageth JC, Juzi C, Grossenbacher H. Delivery after previous cesarean: a risk evaluation. Swiss Working Group of Obstetric and Gynecologic Institutions. Obstet Gynecol 1999;93:332-7. 9. Flamm BL, Goings JF, Liu Y, Wolde-Tsadik G. Elective repeat cesarean delivery versus trial of labor: a prospective multicenter study. Obstet Gynecol 1994;83:927-32. 10. Leung AS, Farmer RM, Leung EK, Medearis AL, Paul RH. Risk factors associated with uterine rupture during a trial of labor after cesarean delivery: a case-control study. Am J Obstet Gynecol 1993;168:1358-63. 11. Zelop CM, Shipp TD, Repke JT, Cohen A, Caughey AB, Lieberman E. Uterine rupture during induced and augmented labor in gravid women with one prior cesarean delivery. Am J Obstet Gynecol 1999;181:882-6. 12. Hook B, Kiwi R, Amini SB, Fanaroff A, Hack M. Neonatal morbidity after elective repeat cesarean section and trial of labor. Pediatrics 1997;100:348-53. 13. Golan A, Langer R, Neuman M, Wexler S, Segev E, David MP. Obstetric outcome in women with congenital uterine malformations. J Reprod Med 1992;37:233-6. 14. Heinonen PK, Saarikoski S, Pystynen P. Reproductive performance of women with uterine anomalies. An evaluation of 182 cases. Acta Obstet Gynecol Scand 1982;61:157-62. 15. Michalas SP. Outcome of pregnancy in women with uterine malformation: evaluation of 62 cases. Int J Gynaecol Obstet 1991; 35:215-9. 16. Sato K, Takahashi K, Shioda K. Uterine rupture during a trial of labor in a case with a unicornuate uterus and a previous cesarean section. Gynecol Obstet Invest 1993;36:124-6. 17. Ravasia DJ, Brain PH, Pollard JK. Incidence of uterine rupture among women with müllerian duct anomalies who attempt vaginal birth after cesarean delivery. Obstet Gynecol 1999;181: 877-81.
Key words: Maternal and fetal or neonatal morbidity and mortality, uterine rupture or dehiscence, vaginal birth after cesarean, tertiary care center
Controversy continues over the management of labor after a previous cesarean delivery. Neither a repeat cesarean delivery nor a trial of labor is without risk. Various authorities have advocated a trial of labor after a previous cesarean delivery and numerous studies have identified risk factors associated with uterine rupture. Although it is a rare event, uterine rupture has potentially catastrophic From the Department of Obstetrics, Gynecology and Reproductive Sciences, University of California. Poster presentation, presented at the Sixty-seventh Annual Meeting of the Pacific Coast Obstetrical and Gynecological Society, Kamuela, Hawaii, November 14-19, 2000. Reprints not available from the authors. Copyright © 2001 by Mosby, Inc. 0002-9378/2001 $35.00 + 0 6/6/114855 doi:10.1067/mob.2001.114855
1576
consequences, and many studies have indicated the relative safety of labor after previous cesarean delivery in carefully selected and counseled patients. At issue are the morbidity and mortality associated with the trial of labor attempt after a cesarean delivery for these women and their babies. The risk of major maternal complications has been reported to be almost twice as likely in women who underwent a trial of labor than in women who chose an elective repeat cesarean.1 The same study also corroborated other data from Miller et al2 that the rates of major and minor complications were elevated and, in fact, were highest in women who elected to have a repeat cesarean delivery and whose history included 3 or more previous deliveries.1 A recent population-based study by Gregory et al3 in a population of women with his-
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Fig 1. Study population.
tories of cesarean deliveries disclosed an unadjusted relative risk for uterine rupture of 1.88 in women who attempted vaginal birth after cesarean (VBAC) with an attributable fraction of 34% compared with women not undergoing labor. The overall uterine rupture rate for women attempting a trial of labor was 0.43%. Further analysis of outcomes by type of delivery hospital showed that women delivering in hospitals with high attempted VBAC rates were more likely to experience successful VBAC than were women delivering in hospitals with low attempted VBAC rates (relative risk, 1.17); women delivering in hospitals with low attempted VBAC rates were also shown to have a higher risk of uterine rupture (relative risk, 1.56).3 This retrospective review was undertaken to examine maternal and perinatal morbidity and mortality outcomes after uterine rupture or scar dehiscence. We conducted this study to test the hypothesis that a trial of labor after cesarean delivery, conducted in an appropriate environment, is safe for mother and child. Material and methods We performed a retrospective chart review of cases of uterine rupture from 1976 to 1998 at the University of California, San Francisco Moffett-Long Hospital. International Classification of Diseases, Ninth Revision, codes for uterine rupture were used to identify patients from hospital medical records and discharge data. The cases identified were then cross-referenced with a separate obstetric database to obtain demographic information, fetal heart rate patterns, umbilical cord gas values, Apgar scores, and neonatal intensive care unit admission data. The primary outcome of interest was uterine rupture. For the purposes of this study, uterine rupture was defined as any disruption of the uterine wall associated with
Table I. Demographics and obstetric history of women with uterine rupture Maternal age (y) Parity 0 1 2–4 ≥5 Birth weight (g) <400 g >4000 g History of cesarean delivery All cases 1 prior cesarean 2 prior cesareans 3 prior cesareans 4 prior cesareans Unknown scar Classical Average length of stay (d) Vaginal delivery (d) Abdominal delivery (d)
29.5 4 (19%) 10 (47.6%) 6 (28.6%) 1 (4.8%) 2978 2 (10.5%) 2 (10.5%) 17 (81%) 10 (58.8%) 2 (11.7%) 0 1 (5.9%) 3 (17.6%) 1 (5.9%) 5 5 5
maternal symptoms or fetal heart rate abnormalities that required surgical intervention to deliver the fetus, repair the uterine wall defect, or perform a hysterectomy. Asymptomatic uterine dehiscence not requiring clinical or surgical intervention was not reported. Twenty-one cases of uterine rupture were identified. Medical record chart review was completed on 19 cases to collect information regarding labor abnormalities, oxytocin augmentation, use of invasive fetal or uterine monitoring, maternal symptoms, anesthesia use, transfusion, infection rates, length of hospital stay, and presence or absence of meconium at the time of delivery. Medical records were not available for two cases; however, data abstracted at the time of delivery were available in the departmental database.
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Table II. Characteristics of study women Case
Age (y)
Obstetric history
Surgical therapy
1 2 3 4 5 6 7 8 9
30 23 26 32 30 35 36 21 36
Gravida 3, para 1, 1 abortion, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 low transverse cesarean Gravida 2, para 1, 1 emergent low transverse cesarean Gravida 6, para 2, 1 low transverse cesarean Gravida 2, para 0, 1 abortion Gravida 2, para 0, 1 abortion Gravida 7, para 4, 1 cesarean, unknown scar
Repeat low transverse cesarean Repeat low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Emergent low transverse cesarean Primary low transverse cesarean Emergent low transverse cesarean Repeat low transverse cesarean
10
23
Gravida 6, para 4, 1 classical cesarean
Hysterectomy
11 12
33 31
Gravida 5, para 4, 4 cesareans Gravida 4, para 2, 1 cesarean, unknown scar
13 14
30 17
Gravida 2, para 1, 1 cesarean, unknown scar Gravida 2, para 0, 1 abortion
Emergent low transverse cesarean Exploratory laparotomy, repair after forceps-assisted vaginal delivery Hysterectomy Exploratory laparotomy, repair after vaginal delivery
15 16
38 28
17
39
18 19
21 28
20 21
26 37
Gravida 1, para 0 Gravida 6, para 3, 1 normal spontaneous vaginal delivery, 2 cesareans, unknown scar Gravida 6, para 5, 3 normal spontaneous vaginal deliveries, 2 low transverse cesareans Gravida 4, para 1, 1 cesarean, unknown scar Gravida 3, para 1, 1 therapeutic miscarriage or abortion, 1 cesarean, unknown scar Gravida 2, para 1, 1 low transverse cesarean Gravida 3, para 1, 1 abortion, 1 low transverse cesarean
Primary low transverse cesarean Emergent low transverse cesarean Repeat low transverse cesarean Repeat low transverse cesarean Repeat low transverse cesarean Exploratory laparotomy, repair Exploratory laparotomy, repair after forceps-assisted vaginal delivery
*Peripartum endomyometritis. †Chorioamnionitis.
Table III. Fetal and neonatal characteristics
Gestational Case age (wk) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
41 38 41 39 40 39 41 39 37 33 30 39 39 23 38 39 41 41 41 25 40
Abnormal fetal heart rate tracings
Umbilical cord artery pH
Neonatal intensive care unit admission
Newborn intubation
No. of days on ventilator
Newborn hospital stay (d)
Late-shaped deceleration, bradycardia No Terminal bradycardia Terminal bradycardia; multiple congenital anomalies Terminal bradycardia Repetitive variable deceleration No Terminal bradycardia Yes No Bradycardia Repetitive variable deceleration Late-shaped deceleration Death before labor Late-shaped deceleration, variable deceleration Repetitive variable deceleration Late-shaped deceleration Unknown Bradycardia Nonviable with anomalies No
7.20 — 7.13 6.80 7.05 7.22 7.33 7.14 6.92 7.19 6.72 7.09 7.14 — 7.24 — 7.05 7.17 6.94 — 7.03
No No Yes Yes Yes No No No Yes Yes Yes No Yes — No No Yes No Yes — No
No No No Yes Yes No No No Yes Yes Yes — Yes — No Yes Yes No Yes — No
0 0 <1 <1 0 0 0 0 3 — 22 0 0 — 0 0 <1 0 0 — 0
2 — 6 13 6 3 2 3 14 16 34 2 3 — 3 4 7 4 4 — 4
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Volume 184, Number 7 Am J Obstet Gynecol
Surgical anesthesia Epidural General endotracheal General endotracheal General endotracheal General endotracheal General endotracheal Epidural General endotracheal Epidural, general endotracheal General endotracheal
Transfusion
Hospital stay (d)
No No No No No No No No Yes
4 4 4 5 8* 4 5 4 6
4 units of packed red blood cells No No
6
5 5
Epidural Epidural
No 2 units of packed red blood cells No No
Epidural
No
4†
Epidural Epidural
No No
4 6
Epidural Epidural
No 1 unit of packed red blood cells
7 6
General endotracheal Epidural Epidural General endotracheal
5 4
4 5
Results The patient population at the University of California, San Francisco Moffett-Long Hospital is primarily composed of a group of private practice patients from middle to upper socioeconomic class and a smaller group of staff patients who are from a lower socioeconomic class. There were 38,027 deliveries at the University of California, San Francisco Moffett-Long Hospital from 1976 to 1998. Fig 1 summarizes the breakdown of these deliveries into those women who were with or without a history of cesarean delivery. Women with histories of cesarean delivery represented 8.7% (3319) of all deliveries. The attempted VBAC rate was 61.3%, of which 65.3% were successful. Twenty-one cases of uterine rupture were identified, resulting in a uterine rupture rate of 0.06%. Two cases were incidental findings; one diagnosis was made at the time of cesarean for failure to progress (case 7), and the other diagnosis was made at manual removal of placenta (case 12). Demographic characteristics, birth weight, and history of cesarean are noted in Table I. Seventeen women with uterine rupture had a history of the following cesarean deliveries: 10 with previous low-transverse uterine incisions, 3 with unknown scars, 1 with a history of classic uterine incision, and 3 with two or more previous ce-
sarean deliveries. Uterine rupture occurred in 4 women who did not have a history of uterine surgery or cesarean delivery. No cases of uterine rupture were identified after elective repeat cesarean delivery. Maternal and neonatal characteristics of the 21 cases of uterine rupture are outlined in Tables II and III. Eighteen were delivered by cesarean after a trial of labor; 3 were delivered vaginally, either spontaneously or assisted. The fetus of one woman (case 10) who presented for labor evaluation was found to be profoundly bradycardic and was promptly taken for an emergent cesarean delivery. The patient had a history of cocaine use and also had a positive drug screening result for cocaine at the time of delivery. Three cases of uterine rupture were identified at the time of delivery or post partum. Two cases of uterine rupture occurred in patients who underwent forceps-assisted vaginal delivery. One case of uterine rupture occurred after spontaneous vaginal delivery in a bicornuate uterus. Hysterectomy was performed in 2 patients; both had a history of cesarean delivery. One woman had a history of a classic cesarean delivery and subsequent vaginal delivery of a 33-week-old fetus with a postpartum diagnosis of a 7-cm rupture in the anterior uterine wall. The second woman had a 9-cm uterine rupture with development of late decelerations and fetal bradycardia. The exact reasons for choosing hysterectomy rather than repair of the rupture were not clarified by the medical record. Information regarding the course of labor was available for the majority of women. Eight patients presented to the hospital in spontaneous labor. A total of 15 women had labor induced or augmented; of these 15 women, 7 had labor induced and 8 had labor augmented with prostaglandin gel or oxytocin. Uterine contractions were monitored with an intrauterine pressure catheter in 8 women. Uterine rupture was suspected clinically in 16 women before delivery from a combination of altered fetal heart rate tracings, maternal pain, increased bleeding, or altered hemodynamic status. Two women presented with increased maternal bleeding (cases 11 and 21), and 5 women reported increased pain (cases 2, 6, 10, 11, and 14). Of the remaining 5 cases of uterine rupture that were not suspected, 2 were asymptomatic, and 3 were identified at the time of delivery or immediately post partum. The decision regarding incision time was examined whenever possible; it was found to be ≤26 minutes. Operative and delivery reports were reviewed for all patients, and there was no report of bladder or rectal lacerations. Three women received blood transfusions; of these 3 women, only 1 had presented with increased bleeding (case 21). Ten women had epidural anesthesia and 8 women had general anesthesia for delivery or laparotomy. There were no maternal deaths in any of the patients who experienced uterine rupture.
1580 Yap, Kim, and Laros
Four women who experienced uterine rupture had no history of uterine surgery or cesarean. Only one of these women had any of the risk factors associated with uterine rupture. This was the patient identified with a bicornuate uterus (case 14). An association of an increased risk for infection, such as chorioamnionitis, endomyometritis, or abdominal wound infection, was unsupported in our study. Chorioamnionitis developed in 2 women, with one case progressing to endomyometritis. None of the women had wound infections. The average length of stay for women who experienced uterine rupture and who delivered by repeat cesarean was not different than that of women who delivered vaginally. The average length of stay for both groups was 5 days. Details on fetal heart rate tracings were available for review in 18 patients only (Table III). Fourteen showed evidence of fetal heart rate abnormalities such as repetitive variable decelerations, late decelerations, bradycardia, or a combination of the three. Cord blood gas data were available for 17 infants. Thirteen had umbilical artery pH >7.0. Four infants had cord blood pH <7.0. Information on Apgar scores was available for 18 infants. Thirteen had 5-minute Apgar scores >6. Two cases of fetal or neonatal death occurred; one was in a 23-week-old fetus whose mother had presented to an outlying hospital (case 14), and the second was in a 25-week-old fetus with Potter’s syndrome (case 20). Four infants had evidence of meconium-stained amniotic fluid at the time of delivery. Nine infants were admitted to the neonatal intensive care unit; 5 of these infants required respiratory support for <24 hours, 1 required respiratory support for 3 days, and another infant who was delivered at 30 weeks’ gestation remained intubated for 22 days. All live-born infants were discharged without evidence of neurologic abnormalities. Average length of nursery stay for the newborns was 7.5 days. Four infants had prolonged hospital courses between 13 and 34 days (Table III; cases 4, 9, 10, and 11). All were delivered at <37 weeks’ gestation, and 3 had umbilical artery pH <7.0 at birth (cases 4, 9, and 11). Two of these infants weighed <2500 g (cases 10 and 11), and 1 had been diagnosed prenatally with a fetal anomaly (case 4). Comment In this study we were able to confirm the relatively small risk of uterine rupture after VBAC. Our attempted VBAC rate was 61.3%, which places our institution in the category of hospitals with a high attempted VBAC rate. Trial of labor after previous cesarean delivery had a 65.3% success rate, with an overall risk of uterine rupture of 0.06%. Specifically, women who had a history of cesarean deliveries had an 0.8% uterine rupture incidence compared with 0.01% in women who did not have a history of cesarean deliveries. In the literature to date, the overall risk of uterine rupture for women undergo-
June 2001 Am J Obstet Gynecol
ing a trial of labor after a cesarean delivery has been reported to be between 0.2 and 1.0%.1, 2, 4-7 Gregory et al3 reported an overall uterine rupture rate of 0.088% in hospitals with high VBAC rates compared with an overall uterine rupture rate of 0.056% in hospitals with low VBAC rates. The most critical issue regarding a trial of labor after a previous cesarean delivery is that of a catastrophic complication, such as uterine rupture with serious maternal and perinatal morbidity or death. McMahon et al1 reported a 1.8-fold increased risk of major complications for women who elected to have a trial of labor compared with the risk for those who chose a repeat cesarean delivery and who previously had 2 or fewer successful vaginal deliveries. The greatest risk occurred in women for whom the trial of labor was unsuccessful.1 Rageth et al8 disclosed an elevated risk of 2 of uterine rupture for patients who had a history of cesarean delivery and were undergoing a trial of labor versus elective repeat cesarean. Nevertheless, all other maternal risks, such as peripartum hysterectomy, thromboembolic complications, and febrile complications, were lower. Our findings are consistent with this report, with 2 patients having to undergo peripartum hysterectomy, 2 patients who experienced febrile events, and 3 patients who required blood transfusions. Previous larger studies have demonstrated complications that were predominantly minor but that were not inconsequential.7, 9 However, one also has to remember that an elective repeat cesarean delivery does not completely eliminate the risk of scar dehiscence or uterine rupture. Numerous studies have been conducted to identify risk factors that predispose patients to uterine rupture. Uterotonic agents have been associated with an increased risk of uterine rupture in labor.7, 8, 10 Rageth et al8 reported a 24% incidence of labor induction among women who experienced uterine rupture compared with a 14% incidence among women who did not experience uterine rupture. In our patient population 71.4% of women who experienced uterine rupture had labor either induced or augmented with prostaglandin E2 or oxytocin. The association of oxytocin induction, oxytocin augmentation, and use of prostaglandin E2 was recently examined by Zelop et al.11 Induction of labor with oxytocin appeared to confer a 4.6-fold increased risk of uterine rupture compared with no oxytocin use among women with one previous cesarean delivery who attempted a trial of labor. In this analysis we describe a case of uterine rupture in a woman with a bicornuate uterus without a prior delivery. A review of the literature showed a high cesarean delivery rate between 27.5% and 63% in patients with uterine anomalies.12-14 We did not find reports on uterine rupture events in these women. There is one case report of a catastrophic uterine rupture event that occurred in a woman with a unicornuate uterus who attempted VBAC.16 Current practice guidelines do not universally
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exclude women with müllerian duct anomalies from attempting VBAC, but recent data show a high rate of uterine rupture (8%) in these women even though there is a high rate of successful VBAC.17 Increased rates of suspected and proven neonatal sepsis necessitating antibiotic interventions and prolonging hospitalizations have been cited as complications of a trial of labor after a previous cesarean delivery. A recent study demonstrated that the increased rates of suspected and proven sepsis were limited to infants delivered by cesarean after a failed trial of labor.12 In fact, they reported that neonatal outcomes after a successful trial of labor were similar to neonatal outcomes after vaginal births and that infants delivered by elective repeat cesarean delivery actually were at increased risk of developing respiratory problems. The perinatal outcomes for our infants were reassuring. After we excluded fetal deaths occurring before labor and in fetuses with lethal congenital anomalies, the perinatal mortality rate was 0%. Our results do not support an association between an increased perinatal death rate and a trial of labor. There was a prolonged hospital course for 4 of the newborns from 13 to 34 days, and at time of discharge all infants were without evidence of neurologic abnormalities or complications. A potential limitation of this study is the relatively small number of uterine rupture events. However, this study comprehensively reflects the VBAC experience at a tertiary care hospital with a consistent style of management over a 22-year period. We believe that our experience accurately portrays the risks of VBAC attempts for mother and child in an optimal practice setting. Another bias is that not all uteri were palpated after birth, and therefore some asymptomatic scar dehiscences or windows may have gone undetected. However, the clinical significance of these asymptomatic defects, which do not require intervention, remains to be seen. For a woman who has had a previous cesarean delivery, a choice must be made between a trial of labor and an elective repeat cesarean delivery. Our results have important implications for counseling these patients. We have demonstrated minimal major morbidities for mother and child when we have been able to recognize uterine scar dehiscence or rupture events and respond expediently. Therefore the hospital setting in which these patients are managed bears further discussion. The ability to recognize the various signs that portend a possible rupture event, such as fetal distress, maternal pain, or hypoten-
sion, and then to address the situation immediately is critical to a good outcome. In this context, we suggest that a trial of labor after a previous cesarean delivery is safe for patients who are managed in a hospital with the capacity to conduct increased surveillance and to accomplish emergent cesarean deliveries and exploratory laparotomies, if necessary. REFERENCES
1. McMahon MJ, Luther ER, Bowes WA, Olshan AF. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med 1996;335:689-95. 2. Miller DA, Diaz FG, Paul RH. Vaginal birth after cesarean: a 10year experience. Obstet Gynecol 1994;84:255-8. 3. Gregory KD, Kors LM, Cane P, Platt LD, Kahn K. Vaginal birth after cesarean and uterine rupture rates in California. Obstet Gynecol 1999;94:985-9. 4. Flamm BL, Newman LA, Thomas SJ, Fallon D, Yoshida MM. Vaginal birth after cesarean delivery: results of a 5-year multicenter collaborative study. Obstet Gynecol 1990;76:750-4. 5. Leung AS, Leung EK, Paul RH. Uterine rupture after previous cesarean delivery: maternal and fetal consequences. Am J Obstet Gynecol 1993;169:945-50. 6. Phelan JP, Clark SL, Diaz F, Paul RH. Vaginal birth after cesarean. Am J Obstet Gynecol 1987;157:1510-5. 7. Rosen MG, Dickinson JC, Westhoff CL. Vaginal birth after cesarean: a meta-analysis of morbidity and mortality. Obstet Gynecol 1991;77:465-70. 8. Rageth JC, Juzi C, Grossenbacher H. Delivery after previous cesarean: a risk evaluation. Swiss Working Group of Obstetric and Gynecologic Institutions. Obstet Gynecol 1999;93:332-7. 9. Flamm BL, Goings JF, Liu Y, Wolde-Tsadik G. Elective repeat cesarean delivery versus trial of labor: a prospective multicenter study. Obstet Gynecol 1994;83:927-32. 10. Leung AS, Farmer RM, Leung EK, Medearis AL, Paul RH. Risk factors associated with uterine rupture during a trial of labor after cesarean delivery: a case-control study. Am J Obstet Gynecol 1993;168:1358-63. 11. Zelop CM, Shipp TD, Repke JT, Cohen A, Caughey AB, Lieberman E. Uterine rupture during induced and augmented labor in gravid women with one prior cesarean delivery. Am J Obstet Gynecol 1999;181:882-6. 12. Hook B, Kiwi R, Amini SB, Fanaroff A, Hack M. Neonatal morbidity after elective repeat cesarean section and trial of labor. Pediatrics 1997;100:348-53. 13. Golan A, Langer R, Neuman M, Wexler S, Segev E, David MP. Obstetric outcome in women with congenital uterine malformations. J Reprod Med 1992;37:233-6. 14. Heinonen PK, Saarikoski S, Pystynen P. Reproductive performance of women with uterine anomalies. An evaluation of 182 cases. Acta Obstet Gynecol Scand 1982;61:157-62. 15. Michalas SP. Outcome of pregnancy in women with uterine malformation: evaluation of 62 cases. Int J Gynaecol Obstet 1991; 35:215-9. 16. Sato K, Takahashi K, Shioda K. Uterine rupture during a trial of labor in a case with a unicornuate uterus and a previous cesarean section. Gynecol Obstet Invest 1993;36:124-6. 17. Ravasia DJ, Brain PH, Pollard JK. Incidence of uterine rupture among women with müllerian duct anomalies who attempt vaginal birth after cesarean delivery. Obstet Gynecol 1999;181: 877-81.