Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery
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《新英格兰医药杂志》
To the Editor: Landon et al. (Dec. 16 issue)1 report an increased risk of hypoxic–ischemic encephalopathy, but not perinatal death, among the infants of women who attempted vaginal birth after prior cesarean delivery as compared with those who underwent planned repeated cesarean delivery. We previously reported an increase by a factor of approximately 12 in the risk of perinatal death in this context2 but have recently shown that there is an inverse relationship between the risk of perinatal death and hospital volume.3 We reanalyzed our data on 124 singleton deliveries complicated by uterine rupture to determine whether neonatal survival after a five-minute Apgar score of less than 4 varied in relation to hospital volume. When hospitals were categorized according to volume (999, 1000 to 1999, 2000 to 2999, 3000 to 3999, and 4000 births per year), the numbers of infants who died were 0 of 4, 0 of 28, 1 of 31, 2 of 26, and 4 of 35, respectively (P for trend = 0.04). The results were similar when the total number of births was used as the denominator.
Although they are based on small numbers, these findings suggest that the availability of facilities for immediate delivery and resuscitation of the infant may determine whether catastrophic uterine rupture results in perinatal death or hypoxic–ischemic encephalopathy. In low-volume centers, elective cesarean section may protect primarily against perinatal death, whereas in high-volume centers, such as those studied by Landon et al., elective cesarean section may protect primarily against hypoxic–ischemic encephalopathy.
Gordon C.S. Smith, M.D., Ph.D.
Cambridge University
Cambridge CB2 2SW, United Kingdom
gcss2@cam.ac.uk
Jill P. Pell, M.D.
Greater Glasgow National Health Services
Glasgow G3 8YU, United Kingdom
References
Landon MB, Hauth JC, Leveno KJ, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004;351:2581-2589.
Smith GCS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002;287:2684-2690.
Smith GCS, Pell JP, Pasupathy D, Dobbie R. Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study. BMJ 2004;329:375-375.
To the Editor: Landon et al. report important findings of a large prospective study on the risks of a trial of labor after prior cesarean delivery. These findings are consistent with those of previous studies1,2 with regard to the increased risk of maternal and perinatal complications, and Landon et al. report the additional finding that use of either oxytocin or prostaglandins significantly increases the risk of uterine rupture. The analysis, however, does not stratify the risk of complications according to the number of previous cesarean deliveries or the number of weeks of gestation. Other studies3,4 have shown that the risk of uterine rupture during labor is nearly five times as great for women with more than one previous cesarean delivery as it is for women with only one previous cesarean delivery. The studies also showed a significantly decreased risk of fetal or neonatal death for women with only one previous cesarean section and less than 42 weeks of gestation. The guidelines of the American College of Obstetricians and Gynecologists5 consider two uterine scars and no vaginal deliveries to be a contraindication to a trial of labor. Stratification of the findings of Landon et al. according to the number of cesarean deliveries and the number of weeks of gestation is essential to interpret the findings and appropriately counsel women regarding the risks of a trial of labor after prior cesarean delivery.
Deborah L. Kaplan, R.P.A., M.P.H.
New York City Department of Health and Mental Hygiene
New York, NY 10007
dkaplan@health.nyc.gov
References
Hibbard JU, Ismail MA, Wang Y, Te C, Karrison T, Ismail MA. Failed vaginal birth after a cesarean section: how risky is it? Am J Obstet Gynecol 2001;184:1365-1371.
Mozurkewich EL, Hutton EK. Elective repeat cesarean delivery versus trial of labor: a meta-analysis of the literature from 1989 to 1999. Am J Obstet Gynecol 2000;183:1187-1197.
Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture in women with one or two prior cesarean deliveries. Am J Obstet Gynecol 1999;181:872-876.
Lieberman E, Ernst EK, Rooks JP, Stapleton S, Flamm B. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol 2004;104:933-942.
ACOG Practice Bulletin 54: vaginal birth after previous cesarean delivery. Obstet Gynecol 2004;104:203-212.
To the Editor: The article by Landon et al. is one of a series of reports over the past five years that address the problems arising among women who undergo a trial of labor after prior cesarean delivery. Examination of the database of the National Perinatal Information Center highlights the effect these reports have had on a subgroup of centers during the period from 1999 to 2003. From the total of 654,095 low-risk, singleton deliveries among women with a prior uterine scar, the rate of repeated cesarean section increased by 31.7 percent, from 61.8 percent in 1999 to 81.4 percent in 2003.
Since "delivery" is the most common hospital procedure, changes in the type of delivery have a significant effect on resource utilization and on cost. For hospitals with a high percentage of payers reimbursing on the basis of one rate, regardless of the type of delivery, the fear is that the additional staff and resources needed to meet the increasing demand for cesarean sections will widen the gap between reimbursement and cost. The perinatal community must work to ensure that reimbursement responds to the current trend.
David E. Gagnon, M.P.H.
Janet H. Muri, M.B.A.
National Perinatal Information Center
Providence, RI 02906
dgagnon@npic.org
To the Editor: Landon et al. included stillbirth, neonatal death, and perinatal hypoxic–ischemic encephalopathy in the category of perinatal outcomes. However, the risks of other outcomes, such as transient tachypnea of the newborn, the respiratory distress syndrome, persistent pulmonary hypertension, and a stay in the neonatal intensive care unit, have been reported to be higher among infants who were born after elective cesarean section than among those born after a trial of labor.1,2 At times, severe respiratory failure in infants has progressed to the point where extracorporeal membrane oxygenation was required.3 These outcomes have a considerable effect in terms of mother–infant bonding, successful establishment of breast-feeding, and costs. Alternatively, infants born by cesarean section after a trial of labor are at increased risk of having septic evaluations and requiring antibiotic therapy.1 These data should also be incorporated into the information provided as part of counseling for women and preparing them for potential risks and benefits. It may be a worthwhile exercise to conduct a cost-effectiveness analysis that includes these outcomes and the effect of a stay in the neonatal intensive care unit based on the number needed to treat for elective cesarean section, which was relatively high in the study by Landon et al.
Prakeshkumar S. Shah, M.D.
Mount Sinai Hospital
Toronto, ON M5G 1X5, Canada
pshah@mtsinai.on.ca
References
Hook B, Kiwi R, Amini SB, Fanaroff A, Hack M. Neonatal morbidity after elective repeat cesarean section and trial of labor. Pediatrics 1997;100:348-353.
Heritage CK, Cunningham MD. Association of elective repeat cesarean delivery and persistent pulmonary hypertension of the newborn. Am J Obstet Gynecol 1985;152:627-629.
Keszler M, Carbone MT, Cox C, Schumacher RE. Severe respiratory failure after elective repeat cesarean delivery: a potentially preventable condition leading to extracorporeal membrane oxygenation. Pediatrics 1992;89:670-672.
The authors reply: Smith and Pell propose that differences in the annual number of deliveries may explain discrepancies between their finding of an increase in the risk of perinatal death associated with a trial of labor after prior cesarean delivery, as compared with planned repeated cesarean delivery,1,2 and our finding of an increase in the risk of hypoxic–ischemic encephalopathy (but not perinatal death) with a trial of labor. The smallest participating center in our study performed approximately 3000 deliveries per year. We agree with these authors that it is plausible that larger institutions may provide a level of support and expertise in response to obstetric emergencies such as uterine rupture that may result in better outcomes. Alternatively, our population may have been at inherently lower risk for adverse outcomes, since a trial of labor was undertaken in 39 percent of our population as compared with 63 percent in the study by Smith et al.
In response to Kaplan's comments, we are currently in the process of comparing outcomes in women with multiple prior cesarean deliveries with those in women with a single prior cesarean delivery. As noted in our article, of the 671 women at term who had more than one prior cesarean section and who underwent a trial of labor, none had infants with hypoxic–ischemic encephalopathy. We had only 365 cases in which women who were at 42 weeks of gestation or more attempted vaginal birth after a prior cesarean delivery.3,4
In response to Gagnon and Muri, the potential economic burden of an increasing rate of repeated cesarean delivery is debatable. Cost analyses have challenged the widely accepted opinion that cesarean deliveries are more expensive than vaginal childbirth.5 Since the cost and complications of a failed trial of labor exceed the cost of an elective cesarean, practitioners must consider potential success rates as vital to the counseling of women who are considering their options for delivery after prior cesarean section.
In response to Shah's comments, we agree that rates of respiratory disorders and requirements for neonatal intensive care are relevant in assessing the benefits versus the costs of elective repeated cesarean delivery. In our study, the number of admissions to the neonatal intensive care unit for term infants in the group of women who underwent a trial of labor was 1399 of 15,338 (9.1 percent) as compared with 1325 of 15,014 (8.8 percent) for those undergoing repeated cesarean delivery (P=0.34); the numbers for transient tachypnea of the newborn were 396 (2.6 percent) and 541 (3.6 percent), respectively (P<0.001). We did not collect data on the overall frequency of septic evaluations and antibiotic therapy in the neonates.
Mark B. Landon, M.D.
Ohio State University College of Medicine
Columbus, OH 43210-1228
landon.1@osu.edu
Sharon Leindecker, M.S., M.B.A.
George Washington University Biostatistics Center
Rockville, MD 20852
Catherine Y. Spong, M.D.
National Institute of Child Health and Human Development
Bethesda, MD 20892
References
Smith GC, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002;287:2684-2690.
Smith GCS, Pell JP, Pasupathy D, Dobbie R. Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study. BMJ 2004;329:375-375.
ACOG Practice Bulletin 54: vaginal birth after previous cesarean delivery. Obstet Gynecol 2004;104:203-212.
Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture in women with one or two prior cesarean deliveries. Am J Obstet Gynecol 1999;181:872-876.
Macario A, El-Sayed YY, Druzin ML. Cost-effectiveness of a trial of labor after previous cesarean delivery depends on the a priori chance of success. Clin Obstet Gynecol 2004;47:378-385.
Although they are based on small numbers, these findings suggest that the availability of facilities for immediate delivery and resuscitation of the infant may determine whether catastrophic uterine rupture results in perinatal death or hypoxic–ischemic encephalopathy. In low-volume centers, elective cesarean section may protect primarily against perinatal death, whereas in high-volume centers, such as those studied by Landon et al., elective cesarean section may protect primarily against hypoxic–ischemic encephalopathy.
Gordon C.S. Smith, M.D., Ph.D.
Cambridge University
Cambridge CB2 2SW, United Kingdom
gcss2@cam.ac.uk
Jill P. Pell, M.D.
Greater Glasgow National Health Services
Glasgow G3 8YU, United Kingdom
References
Landon MB, Hauth JC, Leveno KJ, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004;351:2581-2589.
Smith GCS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002;287:2684-2690.
Smith GCS, Pell JP, Pasupathy D, Dobbie R. Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study. BMJ 2004;329:375-375.
To the Editor: Landon et al. report important findings of a large prospective study on the risks of a trial of labor after prior cesarean delivery. These findings are consistent with those of previous studies1,2 with regard to the increased risk of maternal and perinatal complications, and Landon et al. report the additional finding that use of either oxytocin or prostaglandins significantly increases the risk of uterine rupture. The analysis, however, does not stratify the risk of complications according to the number of previous cesarean deliveries or the number of weeks of gestation. Other studies3,4 have shown that the risk of uterine rupture during labor is nearly five times as great for women with more than one previous cesarean delivery as it is for women with only one previous cesarean delivery. The studies also showed a significantly decreased risk of fetal or neonatal death for women with only one previous cesarean section and less than 42 weeks of gestation. The guidelines of the American College of Obstetricians and Gynecologists5 consider two uterine scars and no vaginal deliveries to be a contraindication to a trial of labor. Stratification of the findings of Landon et al. according to the number of cesarean deliveries and the number of weeks of gestation is essential to interpret the findings and appropriately counsel women regarding the risks of a trial of labor after prior cesarean delivery.
Deborah L. Kaplan, R.P.A., M.P.H.
New York City Department of Health and Mental Hygiene
New York, NY 10007
dkaplan@health.nyc.gov
References
Hibbard JU, Ismail MA, Wang Y, Te C, Karrison T, Ismail MA. Failed vaginal birth after a cesarean section: how risky is it? Am J Obstet Gynecol 2001;184:1365-1371.
Mozurkewich EL, Hutton EK. Elective repeat cesarean delivery versus trial of labor: a meta-analysis of the literature from 1989 to 1999. Am J Obstet Gynecol 2000;183:1187-1197.
Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture in women with one or two prior cesarean deliveries. Am J Obstet Gynecol 1999;181:872-876.
Lieberman E, Ernst EK, Rooks JP, Stapleton S, Flamm B. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol 2004;104:933-942.
ACOG Practice Bulletin 54: vaginal birth after previous cesarean delivery. Obstet Gynecol 2004;104:203-212.
To the Editor: The article by Landon et al. is one of a series of reports over the past five years that address the problems arising among women who undergo a trial of labor after prior cesarean delivery. Examination of the database of the National Perinatal Information Center highlights the effect these reports have had on a subgroup of centers during the period from 1999 to 2003. From the total of 654,095 low-risk, singleton deliveries among women with a prior uterine scar, the rate of repeated cesarean section increased by 31.7 percent, from 61.8 percent in 1999 to 81.4 percent in 2003.
Since "delivery" is the most common hospital procedure, changes in the type of delivery have a significant effect on resource utilization and on cost. For hospitals with a high percentage of payers reimbursing on the basis of one rate, regardless of the type of delivery, the fear is that the additional staff and resources needed to meet the increasing demand for cesarean sections will widen the gap between reimbursement and cost. The perinatal community must work to ensure that reimbursement responds to the current trend.
David E. Gagnon, M.P.H.
Janet H. Muri, M.B.A.
National Perinatal Information Center
Providence, RI 02906
dgagnon@npic.org
To the Editor: Landon et al. included stillbirth, neonatal death, and perinatal hypoxic–ischemic encephalopathy in the category of perinatal outcomes. However, the risks of other outcomes, such as transient tachypnea of the newborn, the respiratory distress syndrome, persistent pulmonary hypertension, and a stay in the neonatal intensive care unit, have been reported to be higher among infants who were born after elective cesarean section than among those born after a trial of labor.1,2 At times, severe respiratory failure in infants has progressed to the point where extracorporeal membrane oxygenation was required.3 These outcomes have a considerable effect in terms of mother–infant bonding, successful establishment of breast-feeding, and costs. Alternatively, infants born by cesarean section after a trial of labor are at increased risk of having septic evaluations and requiring antibiotic therapy.1 These data should also be incorporated into the information provided as part of counseling for women and preparing them for potential risks and benefits. It may be a worthwhile exercise to conduct a cost-effectiveness analysis that includes these outcomes and the effect of a stay in the neonatal intensive care unit based on the number needed to treat for elective cesarean section, which was relatively high in the study by Landon et al.
Prakeshkumar S. Shah, M.D.
Mount Sinai Hospital
Toronto, ON M5G 1X5, Canada
pshah@mtsinai.on.ca
References
Hook B, Kiwi R, Amini SB, Fanaroff A, Hack M. Neonatal morbidity after elective repeat cesarean section and trial of labor. Pediatrics 1997;100:348-353.
Heritage CK, Cunningham MD. Association of elective repeat cesarean delivery and persistent pulmonary hypertension of the newborn. Am J Obstet Gynecol 1985;152:627-629.
Keszler M, Carbone MT, Cox C, Schumacher RE. Severe respiratory failure after elective repeat cesarean delivery: a potentially preventable condition leading to extracorporeal membrane oxygenation. Pediatrics 1992;89:670-672.
The authors reply: Smith and Pell propose that differences in the annual number of deliveries may explain discrepancies between their finding of an increase in the risk of perinatal death associated with a trial of labor after prior cesarean delivery, as compared with planned repeated cesarean delivery,1,2 and our finding of an increase in the risk of hypoxic–ischemic encephalopathy (but not perinatal death) with a trial of labor. The smallest participating center in our study performed approximately 3000 deliveries per year. We agree with these authors that it is plausible that larger institutions may provide a level of support and expertise in response to obstetric emergencies such as uterine rupture that may result in better outcomes. Alternatively, our population may have been at inherently lower risk for adverse outcomes, since a trial of labor was undertaken in 39 percent of our population as compared with 63 percent in the study by Smith et al.
In response to Kaplan's comments, we are currently in the process of comparing outcomes in women with multiple prior cesarean deliveries with those in women with a single prior cesarean delivery. As noted in our article, of the 671 women at term who had more than one prior cesarean section and who underwent a trial of labor, none had infants with hypoxic–ischemic encephalopathy. We had only 365 cases in which women who were at 42 weeks of gestation or more attempted vaginal birth after a prior cesarean delivery.3,4
In response to Gagnon and Muri, the potential economic burden of an increasing rate of repeated cesarean delivery is debatable. Cost analyses have challenged the widely accepted opinion that cesarean deliveries are more expensive than vaginal childbirth.5 Since the cost and complications of a failed trial of labor exceed the cost of an elective cesarean, practitioners must consider potential success rates as vital to the counseling of women who are considering their options for delivery after prior cesarean section.
In response to Shah's comments, we agree that rates of respiratory disorders and requirements for neonatal intensive care are relevant in assessing the benefits versus the costs of elective repeated cesarean delivery. In our study, the number of admissions to the neonatal intensive care unit for term infants in the group of women who underwent a trial of labor was 1399 of 15,338 (9.1 percent) as compared with 1325 of 15,014 (8.8 percent) for those undergoing repeated cesarean delivery (P=0.34); the numbers for transient tachypnea of the newborn were 396 (2.6 percent) and 541 (3.6 percent), respectively (P<0.001). We did not collect data on the overall frequency of septic evaluations and antibiotic therapy in the neonates.
Mark B. Landon, M.D.
Ohio State University College of Medicine
Columbus, OH 43210-1228
landon.1@osu.edu
Sharon Leindecker, M.S., M.B.A.
George Washington University Biostatistics Center
Rockville, MD 20852
Catherine Y. Spong, M.D.
National Institute of Child Health and Human Development
Bethesda, MD 20892
References
Smith GC, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002;287:2684-2690.
Smith GCS, Pell JP, Pasupathy D, Dobbie R. Factors predisposing to perinatal death related to uterine rupture during attempted vaginal birth after caesarean section: retrospective cohort study. BMJ 2004;329:375-375.
ACOG Practice Bulletin 54: vaginal birth after previous cesarean delivery. Obstet Gynecol 2004;104:203-212.
Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture in women with one or two prior cesarean deliveries. Am J Obstet Gynecol 1999;181:872-876.
Macario A, El-Sayed YY, Druzin ML. Cost-effectiveness of a trial of labor after previous cesarean delivery depends on the a priori chance of success. Clin Obstet Gynecol 2004;47:378-385.