Routine revision of uterine scar after prior cesarean section

No. 155-Guidelines for Vaginal Birth After Previous Caesarean Birth

OBJECTIVE

To provide evidence-based guidelines for the provision of a trial of labour (TOL) after Caesarean section.

OUTCOME

Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean (VBAC) and repeat Caesarean section.

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to February 28, 2004, using the key words "vaginal birth after Caesarean (Cesarean) section." The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam.

RECOMMENDATIONS

VALIDATION: These guidelines were approved by the Clinical Practice Obstetrics and Executive Committees of the Society of Obstetricians and Gynaecologists of Canada.

Laparoscopic and vaginal repair of uterine scar dehiscence following cesarean section as detected by ultrasound

INTRODUCTION AND OBJECTIVE

Cesarean section (CS) is the most common operation in obstetrics, with rising incidence in most countries. As a result of this operation late scar dehiscence may occur, which may lead to uterine rupture in a subsequent pregnancy. In this case series we have described sonographic detection of scar dehiscence after CS and feasibility of vaginal or combined laparoscopic and vaginal scar excision and uterine repair.

METHODS

Five consecutive patients underwent vaginal or laparoscopic assisted vaginal approach for repair of suspected scar dehiscence following CS, during a 5 year period. In all cases, transvaginal sonography detected suspicious features of scar dehiscence over the anterior uterine wall. Except of one, all patients had reported recurrent pelvic pain and/or irregular menstrual bleedings. Furthermore all patients planned for a further pregnancy.

RESULTS

Resection of the uterine defect and re-constitution of the uterine wall was successfully achieved in all five patients. There were no intra-operative complications and none of the patients required blood transfusion. The mean operation time was 117 min (27-192). Presence of scar tissue was confirmed on histology in all specimens. Four patients remained free of symptoms with no evidence of recurrent scar dehiscence on sonography over a median follow up of 30 months (3-46). One patient had an uneventful pregnancy 24 months after scar removal and was delivered by repeat CS at 39 weeks' gestation.

CONCLUSION

Patients with a history of CS should undergo transvaginal sonography of the scar region in order to detect latent scar dehiscence in combination with uterine wall thinning prior to planning further pregnancy. In suspected cases, a combined laparoscopic - vaginal or vaginal approach can be employed to repair the defect.

Guidelines for Vaginal Birth After Previous Caesarean Birth

OBJECTIVE

To provide evidence-based guidelines for the provision of a trial of labour (TOL) after Caesarean section.

OUTCOME

Fetal and maternal morbidity and mortality associated with vaginal birth after Caesarean (VBAC) and repeat Caesarean section.

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to February 28, 2004, using the key words "vaginal birth after Caesarean (Cesarean) section". The quality of evidence is described using the Evaluation of Evidence criteria outlined in the Report of the Canadian Task Force on the Periodic Health Exam.

RECOMMENDATIONS

1. Provided there are no contraindications, a woman with 1 previous transverse low-segment Caesarean section should be offered a trial of labour (TOL) with appropriate discussion of perinatal risks and benefits. The process of informed consent with appropriate documentation should be an important part of the birth plan in a woman with a previous Caesarean section (II-2B). 2. The intention of a woman undergoing a TOL after Caesarean section should be clearly stated, and documentation of the previous uterine scar should be clearly marked on the prenatal record (II-2B). 3. For a safe labour after Caesarean section, a woman should deliver in a hospital where a timely Caesarean section is possible. The woman and her health care provider must be aware of the hospital resources and the availability of obstetric, anesthetic, pediatric, and operating-room staff (II-2A). 4. Each hospital should have a written policy in place regarding the notification and (or) consultation for the physicians responsible for a possible timely Caesarean section (III-B). 5. In the case of a TOL after Caesarean, an approximate time frame of 30 minutes should be considered adequate in the set-up of an urgent laparotomy (III-C). 6. Continuous electronic monitoring of women attempting a TOL after Caesarean section is recommended (II-2A). 7. Suspected uterine rupture requires urgent attention and expedited laparotomy to attempt to decrease maternal and perinatal morbidity and mortality (II-2A). 8. Oxytocin augmentation is not contraindicated in women undergoing a TOL after Caesarean section (11-2A). 9. Medical induction of labour with oxytocin may be associated with an increased risk of uterine rupture and should be used carefully after appropriate counselling (II-2B). 10. Medical induction of labour with prostaglandin E2 (dinoprostone) is associated with an increased risk of uterine rupture and should not be used except in rare circumstances and after appropriate counselling (II-2B). 11. Prostaglandin E1 (misoprostol) is associated with a high risk of uterine rupture and should not be used as part of a TOL after Caesarean section (II-2A). 12. A foley catheter may be safely used to ripen the cervix in a woman planning a TOL after Caesarean section (II-2A). 13. The available data suggest that a trial of labour in women with more than 1 previous Caesarean section is likely to be successful but is associated with a higher risk of uterine rupture (II-2B). 14. Multiple gestation is not a contraindication to TOL after Caesarean section (II-2B). 15. Diabetes mellitus is not a contraindication to TOL after Caesarean section (II-2B). 16. Suspected fetal macrosomia is not a contraindication to TOL after Caesarean section (II-2B). 17. Women delivering within 18 to 24 months of a Caesarean section should be counselled about an increased risk of uterine rupture in labour (II-2B). 18. Postdatism is not a contraindication to TOL after Caesarean section (II-2B). 19. Every effort should be made to obtain the previous Caesarean section operative report to determine the type of uterine incision used. In situations where the scar is unknown, information concerning the circumstances of the delivery is helpful in determining the likelihood of a low transverse incision. If the likelihood of a low transverse incision is high, a TOL after Caesarean section can be offered (II-2B).

VALIDATION

These guidelines were approved by the Clinical Practice Obstetrics and Executive Committees of the Society of Obstetricians and Gynaecologists of Canada.

Maternal and perinatal complications with uterine rupture in 142,075 patients who attempted vaginal birth after cesarean delivery: A review of the literature

OBJECTIVE

The purpose of this study was to determine the rate of uterine rupture and its complications as the result of trial of labor after previous cesarean delivery.

STUDY DESIGN

PubMed was searched from 1989 to 2001, with the terms "VBAC, uterine rupture," "trial of labor, uterine rupture," "cesarean delivery, uterine rupture," and "scarred uterus, rupture." For inclusion, reports had to contain data from at least 100 patients with trials of labor that included a description of adverse outcomes. Duplicate reporting from a single institution was excluded. Odds ratios and 95% CIs were calculated.

RESULTS

Seventy-two of the 361 articles (20%) that were identified met the inclusion criteria. A 6.2 per 1000 trial of labor rate of uterine rupture (total=880 uterine ruptures in 142,075 trials of labor) was determined. For every 1000 trials of labor the uterine rupture-related complication rate was 1.8 for packed red blood cell transfusion, 1.5 for pathologic fetal acidosis (cord pH<7.00), 0.9 for hysterectomy, 0.8 for genitourinary injury, 0.4 for perinatal death, and 0.02 for maternal death. The perinatal mortality rate was significantly lower among studies from the United States versus other countries (0.3 vs 0.6; odds ratio, 0.50; 95% CI, 0.26-0.94) and in series that exceeded 1000 patients (0.2 vs 1.7; odds ratio, 7.34; 95% CI, 3.94-13.69).

CONCLUSION

Although relatively uncommon, uterine rupture is associated with several adverse outcomes, depending on the time of the publication and the site and size of the population that was studied.

Estudo da involução uterina por meio da ultra-sonografia (modo-B) em cadelas submetidas a cesariana

Utilizaram-se 15 cadelas gestantes submetidas a cesariana e posteriormente a exames ultra-sonográficos seriados, em modo B (tempo real), para averiguação do diâmetro uterino nos dias 0, 3, 7, 14 e 21 pós-cesariana, com o objetivo de verificar a influência do ato cirúrgico na involução uterina. Os resultados (média e desvio-padrão, em centímetros) registrados para os dias estudados foram, respectivamente: 3,99+0,71; 3,27+0,51; 2,60+0,54; 2,01+0,34; 1,28+0,24. A involução uterina pós-cesariana seguiu o mesmo padrão do puerpério do parto normal, assim como as características das imagens ultra-sonográficas. O parto cesariana não influenciou no padrão de involução uterina.

Routine revision of uterine scar after cesarean section: has it ever been necessary?

Although a trial of labor after cesarean section (VBAC) is successful and relatively safe, few studies have directly addressed the necessity of routine transcervical revision of uterine scar after prior cesarean section. We performed a longitudinal study of 3469 women who had VBAC. In all patients, uterine scar integrity was examined immediately after placental expulsion. The detection rate of uterine scar dehiscence or rupture was 0.23% (8/3469). Only one woman with complete uterine rupture needed immediate laparotomy for severe hemorrhage. Out of seven patients (0.2%), who had evidence of uterine dehiscence, three underwent explorative laparotomy. In conclusion, the potential benefit of routine examination of uterine scar after VBAC is doubtful. Transcervical revision should be performed only in symptomatic patients.

Ultrasonographic evaluation of lower uterine segment to predict the integrity and quality of cesarean scar during pregnancy: a prospective study

A prospective randomized study was conducted to measure the serial thickness of the lower uterine segment (LUS) by transvaginal ultrasonography in a control group of 80 women having no history of uterine surgery and in a study group of 43 women having a history of previous cesarean section (C/S). In the study group, more than 2 mm of thickness of the LUS was considered as good healing and less than 2 mm of thickness as poor healing. After serial sonographic examination, the women with good healing were given trial for labor unless an obstetrical indication for C/S existed. The appearance of the LUS during surgery was compared with antenatal ultrasonographic assessment by direct inspection. Twenty two (79%) of 28 women with a well healed scar had trial labor with the result that 46% had a successful vaginal birth without any uterine rupture of dehiscence. Eight women with poor healing all had elective C/S. Seven women with a 2 mm LUS thickness were individually categorized for delivery mode. Two of those women delivered vaginally. The LUS was found to be thin to translucent in these later two groups. Two mm or less as a criterion for poor healing had the sensitivity and specificity of 86.7% and 100% respectively. The positive predictive value was 100% and the negative predictive value was 86.7%. Ultrasonographic evaluation is effective in predicting the quality of a uterine scar and in differentiating the risk group of probable uterine rupture from the non risk group.