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Trial of labor after cesarean delivery

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Last update: 
September 19, 2009
Authors: 
Amen Ness
Authors: 
Vincenzo Berghella

Key Points

• A woman with a prior cesarean delivery (CD) has two options for mode of delivery in the subsequent pregnancy: a trial of labor after cesarean (TOLAC) to try to achieve a vaginal birth after cesarean (VBAC), or an elective repeat CD (ERCD). • There are no trials to compare the safety, complications, maternal and fetal/neonatal morbidity and mortality between the two options. • Uterine rupture is the main complication associated with TOLAC. • The risk of uterine rupture with a policy of TOLAC depends on several factors: it is 0.7 after 1 prior low transverse CD, and increased with > 1 prior CD, prior vertical scar, prior rupture, induction or augmentation, fetal macrosomia, and possibly interval between delivery <18months, maternal age >30year old, and fever around prior CD. • Rates of all maternal complications except rupture are infrequent and similar with both TOLAC and ERCD. • The bigger fetal risk in women with prior CD is from uterine rupture during TOLAC. Risks of fetal/neonatal morbidity/mortality with term uterine rupture are about: 33% risk of pH<7.00, 40% admission to NICU, 6% risk of HIE, and 1.8% risk of neonatal death (rupture-related risk of neonatal death: 1/10,000) in equipped academic centers. In other centers, these risks are higher, including risk of neonatal death from rupture up to 10-25%. • Compared to ERCD, TOLAC is associated with slightly higher rates of adverse perinatal outcome: cord pH <7.00 (1.5/1,000 TOL), hypoxic-ischemic encephalopathy (8 per 10,000), and perinatal death (excluding malformations) (4.0 per 10,000 with TOL versus 1.4 per 10,000 for ERCD). The overall risk of adverse perinatal outcome is 1/2,000 with TOLAC, slightly higher than with ERCD. • When compared to women without a previous CD (instead of to those having an elective CD), the perinatal mortality for TOLAC is higher than ERCD (10/10,000 versus 0.4/10,000 births), but this rate is only twice as high as that of a no-prior-CD multipara in labor and the same as that of a nullipara in labor. • Absolute contraindications to TOLAC are: o Medical or obstetrical complications that preclude vaginal delivery o Inability to perform emergency CD; o Vertical (classical) uterine scar; o Fundal or peri-fundal complete (from endometrium to serosa) uterine scar from other surgery (eg myomectomy); o Prior uterine rupture. • Successful VBAC rates in the general population of women with previous low transverse uterine incisions vary from 60-80%. Women with prior CD and without prior VBAC may have success rates of ≤50% if they have >2 prior CD, weight >300lbs or BMI >30, macrosomia >4,000gr. No screening tools is sensitive enough to be clinically useful in predicting an unsuccessful trial of labor, and none has been validated prospectively to improve outcomes. A NIH calculator to assess chance of successful VBAC is available.1 • Appropriate counseling including risks as described should be provided to the woman with a prior CD deciding on subsequent mode of delivery. The ultimate decision regarding attempting TOLAC or ERCD is up to the woman. • TOLAC can be offered and suggested to women with risk of uterine rupture <1% (or <2% maximum), and spontaneous labor. If the cervix remains unfavorable with no labor by 40 weeks, ERCD can be suggested. • To minimize risks, an experienced obstetrician, anesthesia, nursing and OR personnel and ability to perform emergency CD must be immediately available at all times (24hours/7days) throughout TOLAC.

  1. 1. www.bsc.gwu.edu/mfmu/vagbirth.html

Introduction

A woman with a prior CD has two options for mode of delivery in the subsequent pregnancy: a TOLAC (to try to acheive VBAC) or an ERCD. There are no randomized trials to compare the safety, complications, maternal and fetal/neonatal morbidity and mortality between the two options. Most studies on TOLAC are retrospective, 1 2 3 4 5 6, often use differing criteria for patient selection, and differ in their ability to correctly ascertain (make sure all cased are included) and define uterine rupture. Studies with <1,000 TOLAC cannot adequately assess maternal and fetal/neonatal morbidity and mortality, as these complications are rare, and meta-analyses 7 8 9 might compound errors from different retrospective studies. Many studies do not differentiate between asymptomatic uterine dehiscence and true acute symptomatic uterine rupture. Clinical care should instead be based large prospective multicenter studies. 10 The main issues regarding TOLAC (attempt at VBAC) are complications and safety (especially in regard to uterine rupture), and success rates at achieving vaginal delivery, as compared to repeat CD.

  1. 1. Smith GS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated wih labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA. 2002;287:2684-90 [II-2; n=15,515]
  2. 2. Wen SW, Rusen ID, Walker M, Liston R, Kramer MS, Basket T, Heaman M, et al. Comparison of maternal mortality and morbidity between trial of labor and elective cesarean section among women with previous cesarean delivery. AJOG 2004;191:1263-9 [II-2; n=308,755]
  3. 3. Lyndon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med. 2001 Jul 5;345(1):3-8 [II-2; n=20,095]
  4. 4. Rageth JC, Juzi C, Grossenbacher H, for the Swiss Working Group. Delivery after previous cesarean: a risk evaluation. Obstet Gynecol 1999;93:332-7 [II-2, n=29,046]
  5. 5. Miller DA, Diaz FG, Paul RH. Vaginal birth after cesarean: A 10-year experience. Obstet Gynecol. 1994 Aug;84(2):255-8. [II-2, n=17,322]
  6. 6. McMahon MJ, Luther ER, Bowes WA,Jr, Olshan AF. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med. 1996 Sep 5;335(10):689-95. [II-2, n=6,138]
  7. 7. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  8. 8. Chauhan SP, Martin JN, Hendrichs CE, Morrison JC, Magann EF. Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: a review of the literature. AJOG 2003;189:408-17 [meta-analysis; 72 studies, n=142,075]
  9. 9. Guise JM, Berlin M, McDonagh M, Osterweil P, Chan B, Helfand M. Safety of vaginal birth after cesarean: A systematic review. Obstet Gynecol. 2004 Mar;103(3):420-9. [meta-analysis; n=20 studies]
  10. 10. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]

Diagnosis/definition

Definitions: TOLAC: Trial of labor after cesarean delivery VBAC: Vaginal delivery after cesarean delivery ERCD: Elective repeat cesarean delivery (before labor) VBAC rate: Number of vaginal births after previous CD per 100 live births to all women with a previous CD. (Same denominator as the CD rate) TOLAC rate: If the average success rate of a TOLAC is about 70% then the TOLAC rate is the VBAC rate / 0.7. Adjusted VBAC rate: Number of women with prior CD and no contraindications to TOLAC who had a vaginal delivery per 100 live births to all women with a previous CD. Successful VBAC rate: Percentage of women with prior CD who attempted a TOLAC and successfully achieved a vaginal birth (VBAC) Successful adjusted VBAC rate: Percentage of women with prior CD and no contraindications to TOLAC achieving a vaginal birth (VBAC) Failed TOLAC (Failed VBAC): TOLAC after CD that results in a repeat CD Uterine Dehiscence: disruption of the uterine muscle with intact serosa. 1 It can include asymptomatic opening if the uterine scar from prior surgery, without protrusion of fetus/fetal organs outside the uterus. Uterine Rupture: Disruption or tear of the uterine muscle and visceral peritoneum, or separation of the uterine muscle with extension to the bladder or broad ligament. It includes symptomatic gross rupture of the uterine scar from prior surgery, with or without protrusion of fetus/fetal organs outside the uterus. 2

  1. 1. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  2. 2. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]

Complications

Uterine rupture is the most serious complication associated with TOLAC. The risk of uterine rupture with TOLAC depends on: number of prior CD, direction of scar, layers of closure, induction or augmentation, maternal age, fever, prior preterm CD, TOL at ≥40weeks, etc. (table) Risk factors for uterine rupture: • Number of prior cesareans Women with ≥2 prior LT CDs are at increased risk of uterine rupture compared to women with 1 prior CD.1 2 3 Most of these ruptures occur in women undergoing induction or augmentation and in those without a prior vaginal delivery. The overall relative risk of rupture is increased (about 2 fold) in women having a TOLAC after 2 low transverse CD compared to 1 (0.9 vs. 1.8%). But the rupture rate in women with a prior vaginal delivery and 2 prior CDs is only 0.5%, no greater than a TOLAC with only one prior CD. 4 The rate of rupture instead increases from 2% with 2 prior CDs up to 5-9% with >2 CDs, and is directly proportional to the number of prior CDs. 5 • Direction of scar Records regarding the prior CD(s) should be obtained, with special care in documentation of direction of scar. If a woman has had a prior vertical (classical) CD, repeat CD is recommended.6 • Layers of closure There is insufficient evidence to assess if the numbers of layers performed at prior uterine closure affects the outcomes for future pregnancies. Randomized trials have insufficient follow up numbers (see CD guideline). Comparing to women who had double-layer closure, women with a single-layer closure have been reported to have either similar or up to a four fold increased risk of uterine rupture compared with those with a double-layer closure.7 8 • Prior rupture As prior uterine rupture is associated with high rates (6-32%) of recurrent rupture with TOLAC, these pregnancies should have an ERCD before labor, possibly around 38weeks.9 • Induction/augmentation There is insufficient, contradicting evidence regarding the effect of induction of rates of complications of TOLAC after prior CD. Almost all studies of sufficient size report a slight increase (up to 1-2%) in rupture with induction of any kind.10 11 12 One trial of women with 1 prior CD, gestational age >37weeks, and Bishop <7 did not show any rupture in either the TOLAC or ERCD groups, but the numbers studied were insufficient to assess the rare complications associated with VBAC.13 The risk of uterine rupture with induction in women who had one prior CD also depends on the type of induction. Risk of rupture are approximately 1.4-2.5 with induction with prostaglandin (with or without oxytocin),14 15 and about 1.1 with oxytocin alone.16 Induction with misoprostol in a third trimester pregnancy with prior CD should be discouraged.17 There is insufficient evidence to assess the safety of mifepristone induction in women with a prior CD.18 Women with prior CD should be made aware of these higher risks of rupture associated with induction. Augmentation may be associated with a very slight increased risk of rupture, eg up to about 1%.19 20 In one study, compared to non-intervention, augmentation with oxytocin for no cervical change after 4 hours of contractions in term gravidas with 1 or 2 unknown uterine scars in early labor was associated with similar rates of CD, but an increase (5 vs 0%) in uterine scar separation; one of these occurred in a woman with 2 prior CDs, one of which vertical, requiring hysterectomy.21 • Birth weight >4,000grams Birth weight >4,000 is associated with a slightly increased risk of rupture.22 • Interval between deliveries Interval between deliveries of <18months is associated with an increased risk (2%) of rupture.23 • Maternal Age Maternal age (>30years old) is associated with an increased risk (1.4%) of uterine rupture.24 • Fever The presence of both intrapartum and postpartum fever at CD, but not either alone, may increase the risk of uterine rupture in a subsequent pregnancy.25 • Twins The risk of rupture or maternal mortality is not increased with prior CD and subsequent TOLAC with twins, with uncommon perinatal morbidity at ≥34 weeks.26 • Post dates The risk of uterine rupture does not increase substantially after 40 weeks, but is increased with induction of labor regardless of gestational age.27 • Prior preterm CD Women with a prior preterm CD are at a minimally increased risk (1.0 vs 0.7%) for uterine rupture in a subsequent pregnancy when compared with women with a previous term CD.28 • Pre-term TOLAC There was a trend toward a lower uterine rupture rate in preterm patients who attempted a VBAC.29 • Second trimester induction of labor Induction of labor in the second trimester with misoprostol is associated with no or minimal risk of uterine rupture after 1 prior low transverse CD, but about 5% risk with ≥2 prior LTCD, and about 50% risk with a prior classical CD.30 Other Maternal Complications31 • Hysterectomy: 1-2/1,000 TOL; similar to ERCD. • Transfusion: uncommon for both TOLAC or ERCD, but slightly more frequent (1.7 vs 1%) with TOLAC (about 2 units pRBC/1,000 TOLAC), and related to the need for CD following a TOLAC. • Thromboembolic disease: about 4/10,000, similar to ERCD (1/1,000). • Endometritis: uncommon and very similar for TOLAC or ERCD (3 vs 2% in academic centers), and related to the need for CD following a TOLAC. • Maternal mortality: about 2/100,000, similar (slightly lower) to ERCD (about 4-5/100,000). • Therefore, rates of all maternal complications except rupture are infrequent and similar with both TOLAC and ERCD. In those women who attempt a TOLAC but end up with a repeat CD in labor (failed VBAC), maternal morbidity is higher than women undergoing an ERCD.32 Fetal/neonatal complications 33 The most serious fetal risk in women with prior CD is from uterine rupture during TOLAC. Risks of fetal/neonatal morbidity/mortality with term uterine rupture are: 33% risk of pH<7.00, 40% admission to NICU, 6% risk of HIE, and 1.8% risk of neonatal death (rupture-related risk of neonatal death: 1/10,000) in equipped academic centers. In other centers, these risks are higher, including risk of neonatal death from rupture up to 10-25%. Compared to ERCD, TOLAC is associated with significantly higher rates of: • Antepartum stillbirth (2-6 per 1000 vs. 1-2 per 1000). This might be due to stillbirths occurring at ≥39weeks with TOLAC, or to encouragement to TOLAC with diagnosis of stillbirth. • Cord pH <7.00 (1.5/1,000 TOLAC)34 • Hypoxic-ischemic encephalopathy (HIE): 8 per 10,000 versus none in the ERCD.The overall risk of rupture-related HIE of 1 in 2,500 TOLAC. • Neonatal death rates: similar between the groups (0.08% vs 0.05%) in academic centers, with the neonatal death rate associated with a rupture at term about 1.8%. • Perinatal death (excluding malformations) rates are 4.0 per 10,000 with TOLAC, versus 1.4 per 10,000 for ERCD. • Overall risk of adverse perinatal outcome is 1/2,000 with TOLAC, slightly higher than with ERCD. When compared to women without a previous CD (instead of to those having an elective CD), the perinatal mortality for TOLAC is higher than ERCD (10/10,000 versus 0.4/10,000 births), but this rate is only twice as high as that of a no-prior-CD multipara in labor and the same as that of a nullipara in labor.35 Absolute contraindications: o Medical or obstetrical complications that preclude vaginal delivery o Inability to perform emergency CD o Vertical (classical) uterine scar o Fundal or peri-fundal complete (from endometrium to serosa) uterine scar from other surgery (eg myomectomy) o Prior uterine rupture Relative contraindications o Multiple uterine scars (eg ≥2 prior CDs) o Any other factor (see above) associated with a risk of rupture of >1%

  1. 1. Macones GA, Cahill A, Pare E, Stamilio DM, Ratcliffe S, Stevens E, et al. Obstetric outcomes in women with two prior cesarean deliveries: Is vaginal birth after cesarean delivery a viable option? American Journal of Obstetrics and Gynecology 2005;192: 1223–9 [II-2]
  2. 2. Caughey AB, Shipp TD, Repke JT, Zelop CM, Cohen A, Lieberman E. Rate of uterine rupture during a trial of labor in women with one or two prior cesarean deliveries. Am J Obstet Gynecol. 1999 Oct;181(4):872-6. [II-2, n=3,891 TOL with 1 or 2 prior CD)]
  3. 3. Asakura H, Myers SA. More than one previous cesarean delivery: a 5-year experience with 435 patients. Obstet Gynecol 1995;85:924-9 [II-2, n=435 TOL with >1 prior CD]
  4. 4. Macones GA, Cahill A, Pare E, Stamilio DM, Ratcliffe S, Stevens E, et al. Obstetric outcomes in women with two prior cesarean deliveries: Is vaginal birth after cesarean delivery a viable option? American Journal of Obstetrics and Gynecology 2005;192: 1223–9 [II-2]
  5. 5. Asakura H, Myers SA. More than one previous cesarean delivery: a 5-year experience with 435 patients. Obstet Gynecol 1995;85:924-9 [II-2, n=435 TOL with >1 prior CD]
  6. 6. ACOG practice bulletin. Vaginal birth after previous cesarean delivery. Number 54, July 2004. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists. [review]
  7. 7. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  8. 8. Bujold E, Bujold C, Hamilton EF, Harel F, Gauthier RJ. The impact of a single-layer or double-layer closure on uterine rupture. Am J Obstet Gynecol. 2002 Jun;186(6):1326-30. [II-2, n=1,980 with 1 or 2 layers]
  9. 9. ACOG practice bulletin. Vaginal birth after previous cesarean delivery. Number 54, July 2004. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists. [review]
  10. 10. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  11. 11. Rageth JC, Juzi C, Grossenbacher H, for the Swiss Working Group. Delivery after previous cesarean: a risk evaluation. Obstet Gynecol 1999;93:332-7 [II-2, n=29,046]
  12. 12. McDonagh MS, Osterweil P, Guise J-M. The benefits and risks of inducing labour in patients with prior caesarean delivery: a systematic review. BJOG 2005;112:1007-15 [meta-analysis; 14 studies (only 2 RCTs)]
  13. 13. Rayburn WF, Gittens LN, Lucas MJ, Gall SA, Martin ME. Weekly administration of prostaglandin E2 gel compared to expectant management in women with previous cesareans. Obstet Gynecol 1999;94:250-4 [RCT, n=294]
  14. 14. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  15. 15. Lyndon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med. 2001 Jul 5;345(1):3-8 [II-2; n=20,095]
  16. 16. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  17. 17. Lyndon-Rochelle M, Holt VL, Easterling TR, Martin DP. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med. 2001 Jul 5;345(1):3-8 [II-2; n=20,095]
  18. 18. Lelaidier C, Baton C, Benifla JL, Ferdandez H, Bouget P, Frydman R. Mifepristone for labour induction after pervious caesarean section. BJOG 1994;101:501-3 [RCT, n=32]
  19. 19. 4. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  20. 20. 19. McDonagh MS, Osterweil P, Guise J-M. The benefits and risks of inducing labour in patients with prior caesarean delivery: a systematic review. BJOG 2005;112:1007-15 [meta-analysis; 14 studies (only 2 RCTs)]
  21. 21. 20. Grubb DK, Kjos SL, Paul RH. Latent labor with an unknown uterine scar. Obstet Gynecol 1996;88:351-5 [RCT, n=197].
  22. 22. 22. Elkousy MA, Sammel M, Stevens E, Peipert JF, Macones G. The effect of birth weight on vaginal birth after cesarean delivery success rates. Am J Obstet Gynecol. 2003 Mar;188(3):824-30. [II-2]
  23. 23. 23. Shipp TD, Zelop C, Repke JT, Cohen A, Lieberman E. Interdelivery interval and risk of symptomatic uterine rupture. Obstet Gynecol 2001;97:175-7 [II-2, n=2,409]
  24. 24. 24. Shipp TD, Zelop C, Repke JT, Cohen A, Caughey AB, Lieberman E. The association of maternal age and symptomatic uterine rupture during a trial of labor after prior cesarean delivery. Obstet Gynecol. 2002 Apr;99(4):585-8. [II-2, n=3,015]
  25. 25. Shipp TD, Zelop C, Cohen A, Repke JT, Lieberman E. Post-cesarean delivery fever and uterine rupture in a subsequent trial of labor. Obstet Gynecol 2003 Jan;101(1):136-139. [II-2]
  26. 26. 28. Varner MW, Leindecker S, Spong CY, Moawad AH, Hauth JC, Landon MB, Leveno KJ, et al. The maternal-fetal medicine unit cesarean registry: trial of labor with twin gestation. AJOG 2005;193:135-40 [II-2, n=186 women with prior CD and subsequent TOL]
  27. 27. Zelop CM, Shipp TD, Cohen A, Repke JT, Lieberman E. Trial of labor after 40 weeks' gestation in women with prior cesarean. Obstet Gynecol. 2001 Mar;97(3):391-3. [II-2]
  28. 28. Sciscione AC, Landon MB, Leveno KJ, et al. Previous preterm cesarean delivery and risk of subsequent uterine rupture. Obstet Gynecol 2008 Mar;111(3):648-53.
  29. 29. Quinones JN, Stamilio DM, Pare E, Peipert JF, Stevens E, Macones GA. The effect of prematurity on vaginal birth after cesarean delivery: Success and maternal morbidity. Obstet Gynecol. 2005 Mar;105(3):519-24. [II-2, n=971 preterm TOL after CD]
  30. 30. 96. Berghella V, Airoldi J, O'Neill A, Einhorn K, Hoffman M. Misoprostol for second trimester pregnancy termination in women with prior caesarean: a systematic review. BJOG 2009; 116(9):1151-7.
  31. 31. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  32. 32. 10. McMahon MJ, Luther ER, Bowes WA,Jr, Olshan AF. Comparison of a trial of labor with an elective second cesarean section. N Engl J Med. 1996 Sep 5;335(10):689-95. [II-2, n=6,138]
  33. 33. 4. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  34. 34. 11. Chauhan SP, Martin JN, Hendrichs CE, Morrison JC, Magann EF. Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: a review of the literature. AJOG 2003;189:408-17 [meta-analysis; 72 studies, n=142,075]
  35. 35. 29. Smith GS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA. 2002;287:2684-90 [II-2, n=>300,000 singleton term births]
Pregnancy Management

Principles

Rates and factors affecting incidence of TOLAC success. The incidence of successful TOLAC in the general population of women with previous low transverse uterine incisions vary from 60-80%.1 2 In tertiary care centers the rates may be higher, about 73-76%. Factors associated with the success or failure of a TOLAC are: o Prior VBAC A previous successful VBAC is the most predictive prognostic indicator (>90% success rate). It is more predictive of a vaginal delivery than a vaginal delivery that occurred before the prior cesarean.3 o Prior indication Breech presentation or other nonrecurring indication (e.g., non-reassuring fetal monitoring) for the prior CD significantly increase the chances for a vaginal delivery (85%). Nevertheless about 60-70% of women undergoing a TOLAC after prior CD for dystocia deliver vaginally. There seems to be no reduction in the rates for a successful TOLAC following a previous CD in the second stage of labor (75-80%), with no increased risk of operative vaginal delivery.4 5 o Number of prior cesarean deliveries About 75-80% of women attempting a TOLAC with a single prior cesarean will deliver vaginally versus about 60-70% with more than one prior cesarean. The majority of studies have shown that the greater the number of prior CD, the lower chances for a vaginal delivery (about 10-15% lower per CD).6 • Maternal obesity Obese women attempting a TOLAC have lower success rates, with women ≥300 pounds having rates of only 15%, while women weighing 200-300 lbs have rates of 56%.7 8 Women ≥300 lbs also have a > 50% chance of infectious morbidity (versus 17.8% in women weighing 200-300 lbs). ERCD in the obese group significantly reduces the infectious morbidity by almost 50% compared to those with a TOL. In a study which excluded women with a prior vaginal delivery, VBAC success rates were 54.6% in women with a BMI≥30 versus 70.5% in women with a normal BMI.9 • Fetal macrosomia There is conflicting evidence regarding the effect of fetal macrosomia (using actual birth weights at delivery) and the success of a TOLAC. The success rates for TOLAC in women with a previous CD and no other births is about 60% in the >4000g group and 71% in the ≤4000g group.10 There is progressive reduction in TOLAC success rates as birth weight increases. With a prior VBAC or a vaginal delivery, there is no success rate below 63% for any of the birth weight strata. With no previous vaginal delivery, VBAC success rates can drop below 50% as neonatal weight exceeds 4000g.11 This success rate can decrease further if the indication for the previous CD is cephalopelvic disproportion or failure to progress. There is no data regarding estimated fetal birth weight and TOLAC success. o Cervical status The more favorable the cervix, the greater the odds for a vaginal delivery. • Induction/augmentation of labor Women who receive oxytocin for induction or augmentation have rates of vaginal delivery about 10% lower than those that are allowed or able to labor spontaneously.12 13 • Post Dates Few studies have addressed the issue of post-term pregnancy and the success of TOLAC. Successful VBAC rates of 65-82% have been reported for women past 40 weeks, with the higher rates in women with prior vaginal deliveries.14 If VBAC is still desired after 40weeks, awaiting the onset of spontaneous labor is a better option than induction before 40 weeks, because the rate of symptomatic uterine rupture is significantly increased for women who are induced regardless of the gestational age compared with spontaneous onset of labor after 40 weeks, and because women induced before or at 40 weeks or enter spontaneous labor after 40 weeks have similar (30-35%) CD rates. It may be reasonable to offer an AROM/oxytocin induction around the EDC to women with a prior vaginal delivery and a favorable cervix. • Uterine Scar Type Vaginal delivery rates appear to be similar for low transverse, low vertical and for unknown incision types.15 • Maternal age There is an inverse association between maternal age and the likelihood of vaginal delivery, with the odds of vaginal delivery significantly greater for younger women.16 • Multiple gestations Vaginal delivery rates of both twins after prior CD range from 65 to 84.2%, and do not seem to differ from success rates in singletons, without increased risk for maternal morbidity or uterine rupture.1718 • Inter-delivery interval Interdelivery interval of <19months may be associated with similar success rates of TOLAC compared to longer intervals, but lower rates if labor is induced.1920 • Pre-term Preterm women with prior CD have a slightly higher VBAC success rate than term patients (82 versus 74%).21 • Prediction tools for vaginal delivery Given the associations above, several different scoring systems have been proposed to predict the likelihood of vaginal delivery or cesarean in women undergoing a VBAC. None of these screening tools is sensitive enough to be clinically useful in predicting an unsuccessful trial of labor, and none has been validated prospectively to improve outcomes.22 One tool 23 was devised based on a large prospective cohort.24

  1. 1. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  2. 2. Chauhan SP, Martin JN, Hendrichs CE, Morrison JC, Magann EF. Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: a review of the literature. AJOG 2003;189:408-17 [meta-analysis; 72 studies, n=142,075]
  3. 3. Hendler I, Bujold E. Effect of prior vaginal birth after cesarean delivery on obstetric outcomes in women undergoing trial of labor. Obstet Gynecol. 2004 Aug;104(2):273-7. [II-2]
  4. 4. Bujold E, Gauthier RJ. Should we allow a trial of labor after a previous cesarean for dystocia in the second stage of labor? Obstet Gynecol. 2001 Oct;98(4):652-5 [II-2, n=214]
  5. 5. Jongen VH, Halfwerk MG, Brouwer WK. Vaginal delivery after previous cesarean section for failure of second stage labour. Br J Obstet Gynecol. 1998;105:10-79-81 [II-2]
  6. 6. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  7. 7. Chauhan SP, Magann EF, Carroll CS, et al. Mode of delivery for the morbidly obese women with prior cesarean delivery: vaginal versus repeat cesarean section. Am J Obstet Gynecol. 2001 ;185:349-54 [II-2, n=30 women >300lbs with TOL after CD]
  8. 8. Durnwald CP, Ehrenberg HM, Mercer BM. The impact of maternal obesity and weight gain on vaginal birth after cesarean section success. Am J Obstet Gynecol. 2004 Sep;191(3):954-7. [II-2]
  9. 9. Edwards RK, Harnsberger DS, Johnson IM, Treloar RW, Cruz AC. Deciding on route of delivery for obese women with a prior cesarean delivery. Am J Obstet Gynecol. 2003 Aug;189(2):385,9; discussion 389-90. [II-2]
  10. 10. Zelop CM, Shipp TD, Repke JT, Cohen A, Lieberman E. Outcomes of a trial of labor following previous cesarean delivery among women with fetuses weighing >4000 g. Am J Obstet Gynecol 2001;185::903-5 [II-2]
  11. 11. Elkousy MA, Sammel M, Stevens E, Peipert JF, Macones G. The effect of birth weight on vaginal birth after cesarean delivery success rates. Am J Obstet Gynecol. 2003 Mar;188(3):824-30. [II-2]
  12. 12. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  13. 13. 12. Guise JM, Berlin M, McDonagh M, Osterweil P, Chan B, Helfand M. Safety of vaginal birth after cesarean: A systematic review. Obstet Gynecol. 2004 Mar;103(3):420-9. [meta-analysis; n=20 studies]
  14. 14. 1. ACOG practice bulletin. Vaginal birth after previous cesarean delivery. Number 54, July 2004. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists. [review]
  15. 15. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  16. 16. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  17. 17. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  18. 18. Varner MW, Leindecker S, Spong CY, Moawad AH, Hauth JC, Landon MB, Leveno KJ, et al. The maternal-fetal medicine unit cesarean registry: trial of labor with twin gestation. AJOG 2005;193:135-40 [II-2, n=186 women with prior CD and subsequent TOL]
  19. 19. Guise JM, Hashima J, Osterweil P. Evidence-based vaginal birth after caesarean section. Best Pract Res Clin Obstet Gynaecol. 2005 Feb;19(1):117-30. [meta-analysis; 61 studies, n=>10,000]
  20. 20. Huang WH, Nakashima DK, Rumney PJ, Keegan KA,Jr, Chan K. Interdelivery interval and the success of vaginal birth after cesarean delivery. Obstet Gynecol. 2002 Jan;99(1):41-4. [II-2, n=81 with interdelivery interval <19months]
  21. 21. 27. Quinones JN, Stamilio DM, Pare E, Peipert JF, Stevens E, Macones GA. The effect of prematurity on vaginal birth after cesarean delivery: Success and maternal morbidity. Obstet Gynecol. 2005 Mar;105(3):519-24. [II-2, n=971 preterm TOL after CD]
  22. 22. Dinsmoor MJ, Brock EL. Predicting failed trial of labor after primary cesarean delivery. Obstet Gynecol. 2004 Feb;103(2):282-6. [review: prediction]
  23. 23. www.bsc.gwu.edu/mfmu/vagbirth.html
  24. 24. Grobman WA, Lai Y, Landon MB, et al. Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstet Gynecol 2007;109:806-12.

Prenatal care

Patients with contraindications (see above) to TOLAC should receive a ERCD at 39 weeks, or earlier if labor starts or in certain cases (eg prior early uterine rupture). TOLAC can be offered and suggested to women with risk of uterine rupture <1% (or <2% maximum), and spontaneous labor. If the cervix remains unfavorable with no labor by 40 weeks, ERCD can be suggested. Counseling points:1 • TOLAC can be offered to most women with a prior CD, but several safety and success factors should be considered and discussed with the woman. • The composite of maternal complications is slightly higher with TOLAC compared to ERCD group primarily due to the risk of rupture, and the increased risks of a CD in labor. These estimates do not take into account the long term increased risks of repetitive CD and the associated risks of placenta previa and accreta.2 This is why counseling should take in account how many future pregnancies are planned. • The overall risks of serious perinatal complications are about 1 in 2000 TOLAC, which is slightly greater than that of ERCD.3 Combining all poor perinatal outcomes, more than 600 ERCD would need to be performed to prevent one poor perinatal outcome. Although a woman with a TOLAC is at higher risk of uterine rupture than any other group, the risk of perinatal death is similar to that of any nulliparous woman in labor.4 • For the approximately 60-80% of TOLAC women who will deliver vaginally, the maternal and perinatal morbidity and mortality are lower than ERCD. • ERCD is safer than a TOLAC that results in a CD. • Although the risks of TOLAC are higher than ERCD, the absolute risks are small and comparable to other potential complications of labor. • Efforts to reduce the frequency of the first cesarean reduce the need for a TOLAC or repeat CD. • TOLAC should be approached with caution in those with the lowest chance of vaginal delivery and highest risk of rupture: eg avoid induction of labor in those with an unfavorable cervix and no prior vaginal deliveries. All women with a single prior low transverse CD without other indications for a CD are candidates for a TOLAC. Women at lowest risk for adverse outcomes and highest chance for a vaginal delivery include those with a prior vaginal delivery (especially a prior VBAC), in spontaneous labor, with a favorable cervix. The ultimate decision regarding attempting TOLAC or not is up to the patient after appropriate counseling. Most women should decide before term, and their decision should be documented in the medical record. The decision might not be made until term in women who want to assess if spontaneous labor and/or favorable cervix make their chances of complications lower and of success higher. There is no evidence that examining the adequacy of the pelvis benefits outcomes. Prenatal education Individualized prenatal education directed toward avoidance of a cesarean delivery does not increase the rate of vaginal birth after cesarean section.5 Consent: A specific consent for TOLAC or ERCD should be signed by the woman after appropriate counseling. Non-vertex presentation External cephalic version (ECV) can safely be performed in women with a prior CD. The success rate for ECV is similar or higher in women with a prior CD compared to controls without a prior CD (82% vs 61%). Women with a successful version have successful VBAC rates of 65-76%.6 7 Ultrasound of lower uterine segment Due to the uncommon nature of rupture, several thousand women need to be studied to assess if measuring the thickness of the lower uterine segment predicts complications in women with a prior CD who elect TOLAC, and therefore there is insufficient evidence to assess the clinical utility of this screening test. No women with a lower uterine segment thickness of ≥4.5mm seem to have dehiscence or rupture, while the proportion of these complications rises as this thickness decreases, with women with defects or thickness <3.5mm possibly benefiting from ERCD.8 Requirements to minimize risks9 To minimize risks, the following must be immediately available at all times (24hours/7days) throughout TOLAC: • Experienced obstetrician • Anesthesia • Nursing and OR personnel • Ability to perform emergency CD L&D units with >500/1,000 births per year have lower risks of uterine rupture and complications compared to units with less volume.10

  1. 1. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  2. 2. Silver RM, Landon MB, Rouse DJ, et al. maternal morbidity associated with multiple repeat cesaren deliveries. Obstet Gynecol 2006;107:1226-32.
  3. 3. Landon MB, Hauth JC, Leveno KJ, Spong CY, Leindecker S, Varner MW, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med. 2004 Dec 16;351(25):2581-9 [II-2; prospective; n=33,699]
  4. 4. Smith GS, Pell JP, Cameron AD, Dobbie R. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA. 2002;287:2684-90 [II-2, n=>300,000 singleton term births]
  5. 5. Fraser W, Maunsell E, Hodnett E, Moutquin JM, Childbirth Alternatives Post-Cesarean Study Group. Randomized controlled trial of a prenatal vaginal birth after cesarean section education and support program. Am J Obstet Gynecol 1997;176(2):419-25. [RCT; n=1,275]
  6. 6. Flamm BL, Freid MW, Lonky NM, Giles WS, External cephalic version after previous cesarean section. Am J Obstet Gynecol.1991;165:370-2 [II-2]
  7. 7. de Meeus JB, Ellia F, Magnin G. External cephalic version after previous cesarean section: a series of 38 cases. Eur J Obstet Gynecol Reprod Biol. 1998 Oct;81(1):65-8. [II-2]
  8. 8. Rozenberg P, Goffinet F, Philippe HJ, Nisand I. Ultrasonographic measurement of lower uterine segment to assess risk of defects of scarred uterus. Lancet 1996;347:281-84 [II-2, n=642 women with prior CD with ultrasound of lower uterine segment]
  9. 9. ACOG practice bulletin. Vaginal birth after previous cesarean delivery. Number 54, July 2004. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists. [review]
  10. 10. Wen SW, Rusen ID, Walker M, Liston R, Kramer MS, Basket T, Heaman M, et al. Comparison of maternal mortality and morbidity between trial of labor and elective cesarean section among women with previous cesarean delivery. AJOG 2004;191:1263-9 [II-2; n=308,755]

Delivery

Detecting Rupture • Fetal heart rate (FHR) disturbances are the most common (but not universal) sign of uterine rupture (55–85%). The most commonly reported FHR disturbance is repetitive progressively severe variable decelerations and prolonged bradycardia, although in most cases they are not caused by rupture. Nevertheless, in women with a prior cesarean delivery, in the presence of such FHR disturbances, uterine rupture must be considered. • Abdominal pain over the area of the prior uterine scar is a poor predictor of uterine rupture. Epidural usually does not mask rupture. Epidural should not be withheld in women attempting TOLAC. • Intrauterine pressure catheter (IUPC) monitoring has not been shown to be helpful. • Significant loss of fetal station especially in the second stage may occur with rupture, but is of limited predictive value. • There is insufficient data to assess the utility of explore the uterus after VBAC. Cost-effectiveness: Cost savings with TOLAC may occur only if success rate ≥70%.

Historic notes

Until the late 1970’s “Once a cesarean always a cesarean” was the general clinical management followed by most obstetricians. A classical uterine incision was used until the 1920’s, when the low transverse (LT) incision was introduced. The LT incision was associated with a ten times lower incidence of uterine rupture in labor than the classical incision. Based on studies in the 1970’s, when the TOLAC rate was very low, the National Institute of Health (NIH; 1980) and the American College of Obstetricians and Gynecologists (ACOG; 1988) suggested that a TOL after low transverse cesarean delivery is a reasonable option.1 In response to these recommendations, the TOLAC rate in the US increased from 3.5% in 1980 to 28.3% in 1996. As more TOLAC were attempted, more ruptures were seen and related litigation also increased. As a result, incidence of TOLAC has decreased to 8.5% in the USA in 2007 (figure 1). After declining until about 1997, overall incidence of CD have increased to 32% in the USA in 2007. 2

  1. 1. ACOG practice bulletin. Vaginal birth after previous cesarean delivery. Number 54, July 2004. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists. [review; new Bulletin due in 2010]
  2. 2. http://www.cdc.gov/nchs/fastats/births.htm

Tables

Figures

Rates of total and primary cesarean delivery and of VBAC from 1989-2003

Rates of total and primary cesarean delivery and of VBAC from 1989-2003