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ORIGINAL RESEARCH |
From the Department of Obstetrics and Gynecology, Hôpital Ste-Justine and Université de Montréal, Montreal, Quebec, Canada
Address reprint requests to: Robert J. Gauthier, MD, Department of Obstetrics and Gynecology, Hôpital Ste-Justine and Université de Montréal, 3175 Côte Ste-Catherine, Montreal, Quebec, Canada H3T 1C5; E-mail: robert_gauthier{at}ssss.gouv.qc.ca.
| ABSTRACT |
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METHODS: Data from all patients who underwent trial of labor after a previous cesarean between 1990 and 2000 at our tertiary care institution were analyzed. Medical records were reviewed and data collected for the following variables: indication for the previous cesarean, birth weight and cervical dilatation at previous cesarean delivery, as well as the mode of delivery (spontaneous, vacuum, forceps, cesarean) and the birth weight for the subsequent pregnancy. Pearsons
2 test and one-way analysis of variance were used for statistical analyses.
RESULTS: There were 2002 patients included in the study. Two hundred fourteen (11%) had their previous cesarean for dystocia in the second stage of labor, 654 (33%) for dystocia in the first stage of labor, and 1134 (57%) for other indications. The vaginal birth after cesarean success rate was 75.2% (P = .015 vs other indications), 65.6% (P < .001 vs other indications), and 82.5%, respectively. The rate of operative vaginal delivery was 15%, 12%, and 10% (P = .109).
CONCLUSION: A trial of labor is reasonable in women whose previous cesarean was for dystocia in the second stage of labor. In this series, patients who underwent a trial of labor after a previous cesarean for dystocia in the second stage had 75.2% (95% confidence interval 69.5, 81.0) chance of achieving vaginal delivery.
Most women who undertake a trial of labor after a previous cesarean delivery will achieve a successful vaginal birth, but those who fail are at higher risk of maternal morbidity than those who choose elective repeat cesarean.1 Many researchers have tried to find predictive factors of successful vaginal birth after cesarean (VBAC),2,3 the indication of the previous cesarean being one of these factors. When the indication for the previous cesarean is failure to progress secondary to cephalopelvic disproportion, the rate of successful VBAC is lower than when the indication is a nonrecurrent cause.4,5 It has been proposed by Hoskins and Gomez that a previous cesarean for dystocia in the second stage of labor is associated with a very high rate of failed trial of labor for the subsequent pregnancy.6 Contrary to this study, three studies with small numbers of patients showed a good success rate.79 An increased incidence of operative vaginal delivery has also been reported in these patients.10 The goal of our study was to evaluate the rate of successful trial of labor and the rate of operative vaginal delivery in patients with a previous cesarean for dystocia in the second stage of labor.
| MATERIALS AND METHODS |
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We divided patients into three groups according to the indication for previous cesarean. Group 1 was composed of those who had a previous cesarean for dystocia in the second stage of labor; group 2 included those who had a cesarean for dystocia in the first stage of labor; and group 3 for those who had a cesarean for any other (nonrecurrent) indication, which served as a control group. The rate of spontaneous vaginal delivery, operative vaginal delivery (vacuum or forceps), and cesarean was calculated for each group. Differences between groups were assessed through proportion comparisons using Pearsons
2 test and comparisons of means using one-way analysis of variance adjusted for inequality of variance when Brown-Forsythe homogeneity of variances test was significant.11 When a statistical difference between groups was found, post hoc tests were performed to test the differences against the control group; when variances were considered equal, we used Dunnetts rule, otherwise we used Bonferronis rule. All tests were performed with an overall significance level of 5%, that is, P < .05 was considered statistically significant. Statistical analysis was performed using SAS release 6.12-TS060 (SAS Institute Inc., Cary, NC).
| RESULTS |
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Table 1
compares the patients characteristics. There were small differences between groups for maternal age and gestational age. Birth weight at the previous and subsequent pregnancy were higher in patients with a previous history of dystocia (groups 1 and 2) compared with that in the control group. Groups 1 and 2 also had a higher rate of primiparous patients and a lower rate of patients with a previous vaginal delivery compared with the control group.
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| DISCUSSION |
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Furthermore, our rate of instrumental vaginal delivery of 15% was much lower than the rate of 48% reported by Jongen et al.10 The main indication for the instrumental delivery was not mentioned in this study. In our series, most of the cesareans in group 1 were performed for dystocia in the second stage. In this situation, the experience and the preference of the obstetrician to perform an instrumental delivery or a cesarean will obviously influence the mode of delivery. This could be one reason why the rates of successful VBAC and instrumental delivery were higher in the Jongen study.
In conclusion, patients who have had a previous cesarean for dystocia in the second stage of labor should not be discouraged from attempting VBAC. The majority of these patients will achieve full cervical dilatation and a successful VBAC.
| Footnotes |
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Received January 23, 2001. Received in revised form April 19, 2001. Accepted May 24, 2001.
| REFERENCES |
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2. Troyer LS, Parisi VM. Obstetric parameters affecting success in a trial of labor: Designation of a scoring system. Am J Obstet Gynecol 1992;167:1099114.[Medline]
3. Pickhardt MG, Martin JN Jr, Meydrech EF, Blake PG, Martin RW, Perry KG Jr, et al. Vaginal birth after cesarean delivery: Are they useful and valid predictors of success or failure? Am J Obstet Gynecol 1992;166:18119.[Medline]
4. Miller DA, Diaz PG, Paul RH. Vaginal birth after cesarean: A 10-year experience. Obstet Gynecol 1994;84: 2558.
5. Rosen MG, Dickinson JC. Vaginal birth after cesarean: A meta-analysis of indicators for success. Obstet Gynecol 1990;76:8659.[Medline]
6. Hoskins IA, Gomez JL. Correlation between maximum cervical dilatation at cesarean delivery and subsequent vaginal birth after Cesarean delivery. Obstet Gynecol 1997;89:5913.[Abstract]
7. Ollendorff D, Goldberg J, Minogue J, Socol M. Vaginal birth after cesarean section for arrest of labor: Is success determined by maximum cervical dilatation during the prior labor? Am J Obstet Gynecol 1988;159:6369.[Medline]
8. Impey L, OHerlihy C. First delivery after cesarean delivery for strictly defined cephalopelvic disproportion. Obstet Gynecol 1998;92(5):799803.[Abstract]
9. Duff P, Southmayd K, Read J. Outcome of trial of labor in patients with a single previous low transverse cesarean section for dystocia. Obstet Gynecol 1988;71:3804.
10. Jongen VHWM, Halfwerk MGC, Brouwer WK. Vaginal delivery after previous caesarean section for failure of second stage of labour. Br J Obstet Gynaecol 1998;105: 107981.[Medline]
11. Snedecor GW, Cochran WG. Statistical methods, 6th ed. Ames, Iowa. The Iowa State University Press, 1967.
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L. Carbillon, M. Uzan, A. Batallan, E. Bujold, S. H. Mehta, and R. J. Gauthier Should We Allow a Trial of Labor After a Previous Cesarean for Dystocia in the Second Stage of Labor? Obstet. Gynecol., March 1, 2002; 99(3): 520 - 521. [Full Text] [PDF] |
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