Intrapartum predictors of uterine rupture

No. 382-Trial of Labour After Caesarean

OBJECTIVE

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

OUTCOMES

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

EVIDENCE

MEDLINE database was searched for articles published from January 1, 1995, to October 31, 2017 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.

VALIDATION

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

RECOMMENDATIONS

Interobserver agreement in analysis of cardiotocograms recorded during trial of labor after cesarean

Introduction: To examine interobserver agreement in intrapartum cardiotocography (CTG) classification in women undergoing trial of labor after a cesarean section (TOLAC) at term with or without complete uterine rupture. Materials and methods: Nineteen blinded and independent Danish obstetricians assessed CTG tracings from 47 women (174 individual pages) with a complete uterine rupture during TOLAC and 37 women (133 individual pages) with no uterine rupture during TOLAC. Individual pages with CTG tracings lasting at least 20 min were evaluated by three different assessors and counted as an individual case. The tracings were analyzed according to the modified version of the Federation of Gynaecology and Obstetrics (FIGO) guidelines elaborated for the use of STAN (ST-analysis). Occurrence of defined abnormalities was recorded and the tracings were classified as normal, suspicious, pathological, or preterminal. The interobserver agreement was evaluated using Fleiss' kappa. Results: Agreement on classification of a preterminal CTG was almost perfect. The interobserver agreement on normal, suspicious or pathological CTG was moderate to substantial. Regarding the presence of severe variable decelerations, the agreement was moderate. No statistical difference was found in the interobserver agreement between classification of tracings from women undergoing TOLAC with and without complete uterine rupture. Conclusions: The interobserver agreement on classification of CTG tracings from high-risk deliveries during TOLAC is best for assessment of a preterminal CTG and the poorest for the identification of severe variable decelerations.

Tocogram characteristics of uterine rupture: a systematic review

PURPOSE

Timely diagnosing a uterine rupture is challenging. Based on the pathophysiology of complete uterine wall separation, changes in uterine activity are expected. The primary objective is to identify tocogram characteristics associated with uterine rupture during trial of labor after cesarean section. The secondary objective is to compare the external tocodynamometer with intrauterine pressure catheters.

METHODS

MEDLINE, EMBASE, and the Cochrane library were systematically searched for eligible records. Moreover, clinical guidelines were screened. Studies analyzing tocogram characteristics of uterine rupture during trial of labor after cesarean section were appraised and included by two independent reviewers. Due to heterogeneity, a meta-analysis was only feasible for uterine hyperstimulation.

RESULTS

Thirteen studies were included. Three tocogram characteristics were associated with uterine rupture. (1) Hyperstimulation was more frequently observed compared with controls during the delivery (38 versus 21 % and 58 versus 53 %), and in the last 2 h prior to birth (19 versus 4 %). Results of meta-analysis: OR 1.68 (95 % CI 0.97-2.89), p = 0.06. (2) Decrease of uterine activity was observed in 14-40 % and (3) an increasing baseline in 10-20 %. Five studies documented no changes in uterine activity or Montevideo units. A direct comparison between external tocodynamometer and intrauterine pressure catheters was not feasible.

CONCLUSIONS

Uterine rupture can be preceded or accompanied by several types of changes in uterine contractility, including hyperstimulation, reduced number of contractions, and increased or reduced baseline of the uterine tonus. While no typical pattern has been repeatedly reported, close follow-up of uterine contractility is advised and hyperstimulation should be prevented.

Can Intrapartum Cardiotocography Predict Uterine Rupture among Women with Prior Caesarean Delivery?: A Population Based Case-Control Study

OBJECTIVE

To compare cardiotocographic abnormalities recorded during labour in women with prior caesarean delivery (CD) and complete uterine rupture with those recorded in controls with prior CD without uterine rupture.

STUDY DESIGN

Women with complete uterine rupture during labour between 1997 and 2008 were identified in the Danish Medical Birth Registry (n = 181). Cases were validated by review of medical records and 53 cases with prior CD, trial of labour, available cardiotocogram (CTG) and complete uterine rupture were included and compared with 43 controls with prior CD, trial of labour and available CTG. The CTG tracings were assessed by 19 independent experts divided into groups of three different experts for each tracing. The assessors were blinded to group, outcome and clinical data. They analyzed occurrence of defined abnormalities and classified the traces as normal, suspicious, pathological or pre-terminal according to international guidelines (FIGO).

RESULTS

A pathological CTG during the first stage of labour was present in 77% of cases and in 53% of the controls (OR 2.58 [CI: 0.96-6.94] P = 0.066). Fetal tachycardia was more frequent in cases with uterine rupture (OR 2.50 [CI: 1.0-6.26] P = 0.053). Significantly more cases showed more than 10 severe variable decelerations compared with controls (OR 22 [CI: 1.54-314.2] P = 0.022). Uterine tachysystole was not correlated with the presence of uterine rupture.

CONCLUSION

A pathological cardiotocogram should lead to particular attention on threatening uterine rupture but cannot be considered a strong predictor as it is common in all women with trial of labour after caesarean delivery.

A randomised controlled trial comparing 30 mL and 80 mL in Foley catheter for induction of labour after previous Caesarean section

Inducing labour with a Foley balloon catheter rather than using oxytocin or prostaglandins is considered to be less risky if the uterus is scarred.¹ It is not known if more fluid in the balloon is more effective without being more dangerous. Volumes of 80 mL and 30 mL were compared in 154 eligible women. Mode of delivery, duration of labour and delivery within 24 h were similar in both groups. However, the second group required oxytocin more frequently. Though more scar dehiscences occurred in the first group, the difference was not significant.

Variables influencing the integrity of lower uterine segment in post-cesarean pregnancy

BACKGROUND

There is significant increase in proportion of cases with previous cesarean delivery requiring obstetric care. The available literature fails to provide uniform opinion on each woman's characteristics to identify risk of uterine rupture while planning trial of labor after cesarean.

OBJECTIVE

To study the association of abnormal lower uterine segment with some of the present and previous obstetric variables including patient characteristics and surgical techniques at previous cesarean operation.

MATERIALS AND METHODS

Consenting consecutive 96 post-cesarean singleton pregnancies admitting after 36 weeks gestation at the same facility from July 2011 to December 2012 for repeat cesarean, were studied. Only the cases with cephalic presentation and vertex as presenting part, having no placenta previa, polyhydramnios, uterine anomaly or fibroid and those who had previous one lower segment cesarean were recruited. Based on the intra-operative finding the lower uterine segment (LUS) was categorized into those having a normal and abnormal (grades 2-4) LUS. Sonographic assessment of LUS thickness and any abnormalities if any were noted. The findings of abnormal LUS (direct observation at surgery and sonographic impression within a week before surgery) were looked for association with some of the present and previous obstetric variables including patient characteristics and surgical techniques at previous cesarean operation using Student t, Chi square or Fisher's exact test for analysis as appropriate. Receiver operating curve analysis was used to determine the optimal cut off value for prediction of LUS integrity by ultrasound.

RESULTS

Of the women recruited for the study, 36 were admitted in early labor and ultrasound evaluation of LUS was performed in 48 of the remaining 60 women admitted antenatal for elective cesarean delivery. There were 38 abnormal LUS (39.6%) with 22 of them (57.9%) graded as 'thinned out LUS'. The incidence of scar dehiscence (grade 3, cases 5) was 5.2% of 96 cases and there were no cases of scar rupture. Proportion of cases with abnormal LUS was significantly high when primary cesarean was done in preterm (p = 0.02); it was a single layer uterine closure (p = 0.02), and inter-cesarean interval was 54 months (p = 0.01). Abnormal LUS was also seen to be associated with maternal age beyond 35 years (p = 0.2), when cesarean was performed in labor (p = 0.5), following 18 h of rupture of membranes (p = 0.75), for a baby weight more than 3 kg (p = 0.4), and different suture materials (polyglactin 910 and chromic catgut) were used to close uterus at primary cesarean delivery (p = 0.1), and also if they had post-partum fever (p = 0.3). Ultrasound measurement of LUS by abdominal scan correlated with the intra-operative LUS grading and a thickness of more than 3.2 mm within a week before delivery and was seen to be the safe cut off above which most of the women had a normal LUS (sensitivity 92.3%, specificity 81.1%).

CONCLUSION

Factors at primary cesarean operation significantly influence the state of LUS at term in subsequent pregnancy .

Persistent abdominal pain over uterine scar during labor as a predictor of delivery complications

OBJECTIVE

To evaluate the significance of persistent lower abdominal pain in women with previous cesarean delivery.

METHODS

Various maternal outcomes were compared between women who underwent repeated cesareans owing to persistent lower abdominal pain (study group) and women who underwent repeated cesareans without persistent abdominal pain (control group).

RESULTS

The incidence of uterine rupture was significantly higher in the study group than in the control group (8/81 [9.9%] vs 0/119 [0.0%]; P<0.001). While all women with persistent lower abdominal pain and uterine rupture had an additional sign or symptom, only 6/73 (8.2%) women with persistent abdominal pain without uterine rupture had any additional symptoms (P<0.001). There was no difference in incidence of uterine scar dehiscence between the groups. However, the hospitalization period was significantly longer in the study group (4 vs 3.7days; P<0.05). Trial of labor was a contributing factor to uterine rupture.

CONCLUSION

Isolated persistent lower abdominal pain in women with previous cesarean is a poor indicator of uterine rupture. However, the positive predictive value for uterine rupture is 57% when an additional sign or symptom is present. Dehiscence of the uterine scar is relatively common and it is not associated with persistent abdominal pain.

Uterine rupture associated with VBAC

Uterine rupture during attempted vaginal birth after cesarean is a rare, but serious complication and can result in death or long-term disability. Several factors can increase the risk of uterine rupture during vaginal birth after cesarean and adequate counseling is necessary. Current literature suggests that timely diagnosis and delivery of the fetus is necessary for optimal outcome.

Injections during labor and intrapartum-related hypoxic injury and mortality in rural southern Nepal

OBJECTIVE

To estimate the association between unmonitored use of injections during labor and intrapartum-related neonatal mortality and morbidity among home births.

METHODS

Recently delivered women in Sarlahi, Nepal, reported whether they had received injections during labor. Data on breathing and crying status at birth, time to first breath, respiratory rate, sucking ability, and lethargy were gathered. Neonatal respiratory depression (NRD) and encephalopathy (NE) were compared by injection receipt status using multivariate regression models.

RESULTS

Injections during labor were frequently reported (7108 of 22352 [31.8%]) and were predominantly given by unqualified village "doctors." Multivariate analysis (excluding facility births and complicated deliveries) revealed associations with intrapartum-related NRD (relative risk [RR] 2.52; 95% CI, 2.29-2.78) and NE (RR 3.48; 95% CI, 2.46-4.93). The risks of neonatal death associated with intrapartum-related NRD (RR 3.78; 95% CI, 2.53-5.66) or NE (RR 4.47; 95% CI, 2.78-7.19) were also elevated.

CONCLUSION

Injection during labor was widespread at the community level. This practice was associated with poor outcomes and possibly related to the inappropriate use of uterotonics by unqualified providers. Interventions are required to increase the safety of childbirth in the community and in peripheral health facilities. Parent trial registered at clinicaltrials.gov (NCT00 109616).

Vaginal birth after cesarean and trial of labor after cesarean: what should we be recommending relative to maternal risk:benefit?

Trial of labor after cesarean (TOLAC) delivery is currently a hot obstetrical topic owing to the acute rise in the rate of cesarean deliveries, both primary and repeat. When the physician and patient are considering TOLAC, several factors should be considered: risk of uterine rupture, contraindications, minimizing risk and morbidity, choosing the appropriate candidate and whether or not to induce. Each patient has her own set of individual risk factors that may decrease her chance of successful vaginal birth after cesarean delivery or increase her risks with TOLAC. Once all things are considered, the risk:benefit of TOLAC should be weighed up before a decision is reached. Each of these factors is discussed in respect to maternal risk:benefit, with the focus on evidence presented in the current literature.

The influence of intrapartum factors on risk of uterine rupture and successful vaginal birth after cesarean delivery

Cesarean delivery is common and increasing over time. A prior cesarean birth increases the risk of both elective and emergency cesarean births and uterine rupture in a subsequent pregnancy. A range of factors, including labor characteristics, may influence the risk of these outcomes in the next pregnancy. Intrapartum factors associated with successful vaginal birth and lower risk of uterine rupture include the spontaneous onset of labor and advanced cervical dilatation. In contrast, need for induction and augmentation of labor are both factors associated with an increased likelihood of unsuccessful vaginal birth and risk of uterine rupture.

Identifying risk factors for uterine rupture

Uterine rupture, whether in the setting of a prior uterine incision or in an unscarred uterus, is an obstetric emergency with potentially catastrophic consequences for both mother and child. Numerous studies have been published regarding various risk factors associated with uterine rupture. Despite the mounting data regarding both antepartum and intrapartum factors, it currently is impossible to predict in whom a uterine rupture will occur. This article reviews the data regarding these antepartum and intrapartum predictors for uterine rupture. The author hopes that the information presented in this article will help clinicians assess an individual's risk for uterine rupture.