Vaginal birth after Caesarean section: review of antenatal predictors of success

Epistemic Silences and Experiential Knowledge in Decisions After a First Cesarean: The case of a vaginal birth after cesarean calculator

Evidence-based obstetrics can employ statistical models to justify greater use of cesareans, sometimes excluding experiential elements from informed decision making. Over the past decade, prenatal providers adopted a vaginal birth after cesarean (VBAC) calculator designed to support patients in making informed decisions about their births by estimating their probability for a VBAC. Among other factors, the calculator used race and ethnicity to make its estimate, assigning lower probabilities for a successful VBAC to Black and Hispanic patients. I analyze how a diverse group of women and their providers engaged with the VBAC calculator. Some providers used low calculator scores to remove a shared decision-making model by prescriptively counseling Black and Hispanic women who desired a VBAC into undergoing repeat cesareans. Consequently, women racialized by the calculator as Black or Hispanic used experiential knowledge to challenge the calculator's assessment of their supposed lesser ability to give birth vaginally.

Patient-Led Approaches to a Vaginal Birth After Cesarean Delivery Calculator

OBJECTIVE

To describe patient approaches to navigating their probability of a vaginal birth after cesarean (VBAC) within the context of prediction scores generated from the original Maternal-Fetal Medicine Units' VBAC calculator, which incorporated race and ethnicity as one of six risk factors.

METHODS

We invited a diverse group of participants with a history of prior cesarean delivery to participate in interviews and have their prenatal visits recorded. Using an open-ended iterative interview guide, we queried and observed these individuals' mode-of-birth decisions in the context of their VBAC calculator scores. We used a critical and feminist approach to analyze thematic data gleaned from interview and visit transcripts.

RESULTS

Among the 31 participants who enrolled, their self-identified racial and ethnic categories included: Asian or South Asian (2); Black (4); Hispanic (12); Indigenous (1); White (8); and mixed-Black, -Hispanic, or -Asian background (4). Predicted VBAC success probabilities ranged from 12% to 95%. Participants completed 64 interviews, and 14 prenatal visits were recorded. We identified four themes that demonstrated a range of patient-led approaches to interpreting the probability generated by the VBAC calculator: 1) rejecting the role of race and ethnicity; 2) reframing failure, finding success; 3) factoring the physical experience of labor; and 4) modifying the probability for VBAC.

CONCLUSION

Our findings demonstrate that a numeric probability for VBAC may not be highly valued or important to all patients, especially those who have strong intentions for VBAC. Black and Hispanic participants challenged the VBAC calculator's incorporation of race and ethnicity as a risk factor and resisted the implication it produced, especially that their bodies were less capable of achieving a vaginal birth. Our findings suggest that patient-led approaches to assessing and interpreting VBAC probability may be an untapped resource for achieving a more person-centered, equitable approach to counseling.

A prospective study of a new prediction model of vaginal birth after cesarean section at a tertiary care centre

Objective:

To create a new and simple model for predicting the likelihood of vaginal birth after cesarean (VBAC) section using variables available at the time of admission.

Materials and Methods:

A prospective observational study was performed at a tertiary care centre in Haryana over a period of 12 months (January 2018 - December 2018) in pregnant women attending the labour room with one previous cesarean section fulfilling the criteria for undergoing trial of labour after cesarean (TOLAC). The sample size was 150. A VBAC score was calculated for each patient using a new prediction model that included variables available at the time of admission such as maternal age, gestational age, Bishop’s score, body mass index, indication for primary cesarean section, and clinically estimated fetal weight. The results of the VBAC scores were correlated with outcomes i.e. successful VBAC or failed VBAC. The chi-square test and Student’s t-test was used for comparison among the groups. Descriptive and regression analysis was performed for the study variables.

Results:

Out of 150 TOLAC cases, 78% had successful VBAC and the remainder (22%) had failed VBAC. The observed probability of having a successful VBAC for a VBAC score of 0-3 was 34%, 4-6 was 68%, 7-9 was 90%, and ≥10 was 97%. The prediction model performed well with an area under the curve of 0.77 (95% CI: 0.68 to 0.85) of the receiver operating characteristics receiver operating characteristic curve.

Conclusion:

The present study shows that the proposed VBAC prediction model is a good tool to predict the outcome of TOLAC and can be used to counsel women regarding the mode of delivery in the current and subsequent pregnancies. Further studies of this model and other such models with different permutations and combinations of variables are required.

Cesarean Delivery and Vaginal Birth After Cesarean Delivery Rates in a First Nations Community-Based Obstetrical Program in Northwestern Ontario

OBJECTIVE

To examine rates of cesarean delivery (CD) and vaginal birth after cesarean delivery (VBAC) and the patient profile in a community-based obstetrical practice.

METHODS

Retrospective data from 2012 to 2017 for the Sioux Lookout Meno Ya Win Health Centre (SLMHC) were compared to data from the 30 hospitals providing the same level of services (Maternity 1b: maternity care by family physicians/midwives with CD and VBAC capacity) and Ontario. SLMHC VBAC patients were then compared to the general SLMC obstetrical population. Data included maternal age, parity, comorbidities, CD, VBAC, neonatal birth weight, and Apgar scores.

RESULTS

The SLMHC obstetrical population differed from comparable obstetrical programs, with significantly higher rates of alcohol, tobacco, and opioid use and a higher prevalence of diabetes. CD rates were significantly lower (25% vs. 28%), and women delivering at SLMHC chose a trial of labour after CD almost twice as often (46% vs. 27%), resulting in a significantly higher VBAC rate (31% vs. 16%). Patients in the VBAC population differed from the general SLMHC obstetrical population, being older (7 years) and of greater parity. The neonates of VBAC patients had equivalent Apgar scores but lower rates of macrosomia and lower birth weights, although the average VBAC birth weight at 3346 g was equivalent to the provincial average.

CONCLUSION

The SLMHC obstetrical program has lower CD and higher VBAC rates than expected, despite prevalent risk factors typically associated with CD. Our study demonstrates that VBAC can be safely performed in well-screened and monitored patients in a rural setting with emergency CD capacity.

Can recurrent cesarean section due to arrest of descent be predicted by newborn weight difference?

OBJECTIVE

To evaluate if newborn weight difference is associated with the mode of delivery in women with a previous cesarean section due to arrest of descent.

STUDY DESIGN

This retrospective cohort analysis included all women admitted to the delivery room of Carmel Medical Center with a singleton fetus at vertex presentation and a prior cesarean section for arrest of descent. A comparison was made between women who had a subsequent successful vaginal birth after cesarean delivery vs. a repeat cesarean section for arrest of descent. The primary outcome was newborn weight difference between the previous cesarean section and the present delivery. Secondary outcomes were gestational age, gravidity, age, induction of labor, previous vaginal birth and epidural analgesia.

RESULTS

Of 179 women with a prior cesarean section due to arrest of descent, 55 women (30.7 %) underwent an elective repeat cesarean section. Of the remaining 124 women, 95 women (76.6 %) achieved a vaginal delivery. Out of the 29 cases who underwent a repeat cesarean section, 18 women had a cesarean section for arrest of descent. Women who achieved vaginal delivery were more likely to be with higher gravidity, a previous vaginal delivery and a lower rate of epidural anesthesia. Following multivariate logistic regression, the women who required a cesarean section due to arrest of descent, had significantly higher birth weight in the current than in the previous pregnancy, compared to women achieving vaginal delivery (Odds Ratio 4.7, CI 95 % 1.4-15.7, P = 0.012).

CONCLUSION

Current birth weight higher than the previous newborn weight in a cesarean section for arrest of descent is associated with lower likelihood of successful vaginal birth after cesarean delivery and therefore should be taken in consideration during fetal weight estimation and the decision on the mode of delivery. This issue should be explored in future prospective large-cohort studies.

VBAC: antenatal predictors of success

To determine antenatal factors that may predict successful vaginal birth after Caesarean section (VBAC), to develop a relevant antenatal scoring system and a nomogram for prediction of vaginal birth after caesarean delivery. A non recurring indication for previous Caesarean section (CS), such as breech presentation or foetal distress, is associated with a much higher successful VBAC rate than recurrent indications, such as cephalopelvic disproportion (CPD). Prior vaginal deliveries are excellent prognostic indicators of successful VBAC, especially if the vaginal delivery follows the prior CS. A low vertical uterine incision does not seem to adversely affect VBAC success rates as compared to a low transverse incision. Maternal obesity and diabetes mellitus adversely affect VBAC outcomes. Foetal macrosomia does not appear to be a contraindication to VBAC, as success rates exceeding 50% are achieved and uterine rupture rates are not increased. An inter-pregnancy interval of <24 months is not associated with a decreased success of VBAC. Success rates decrease when interval increases. Twin gestation does not preclude VBAC. Post-dates pregnancies may deliver successfully by VBAC in greater than two-thirds of cases. There are few absolute contraindications to attempted VBAC. Attempted VBAC will be successful in the majority of attempted cases.

Maternal and neonatal outcomes for women giving birth after previous cesarean

INTRODUCTION

Rising rates of caesarean section (CS) is an issue of particular concern. Recently, there has been research supporting Vaginal Births After Caesarean (VBAC), which is controversial. In Greece, over half of births in the country are by CS, placing Greece among countries with the highest CS rates. The aim of this study was to investigate the prevalence and the factors associated with VBACs and to compare the maternal/neonatal outcomes with a 'non-caesarean' control group.

METHODS

The data were evaluated and retrospectively gathered on archived singleton births, from medical records of a midwifery-led team, between May 2006 and May 2013. The target group of the study included mothers with a previous CS, who had a second birth. The sample consisted of 71 VBAC women and 583 who had normal spontaneous vaginal delivery (NSVD) as the 'non-caesarean' control group.

RESULTS

The duration of labour was longer for the VBACs compared with first-time mothers who gave birth naturally (for duration 481-720 min, 27% vs 10.3%, respectively), episiotomy was more common for VBAC (20.7% vs 7.9%), and epidural analgesia was more often for VBAC (68.4% vs 10%). The percentage of 1-min Apgar score in the range 0-7 in the VBAC group was 5%, and there was no significant difference in women who had NSVD (3.6%). The Apgar score in the 5th minute was always above 8 for both groups.

CONCLUSIONS

Severe maternal and neonatal complications are infrequent, and therefore the necessity arises for further continuous studies to ascertain the safety of VBAC.

Are There Differences between Women who Choose Elective Repeat Caesarean Versus Trial of Labour in St. John's, NL?

OBJECTIVES

To compare the demographic and clinical characteristics between women who chose elective repeat Caesarean section (ERCS) versus trial of labour after Caesarean section (TOLAC) in St. John's, Newfoundland and Labrador (NL).

METHODS

We conducted a retrospective case control study of women with live singleton gestations delivering at term in St. John's, NL between January 1, 2001 and December 31, 2014. Inclusion criteria were women who had a previous single lower segment Caesarean section (LSCS). TOLAC, successful TOLAC, and VBAC rates were calculated. Demographic and clinical characteristics were compared between women who chose ERCS versus TOLAC. Univariate analyses and multiple logistic regression analyses were performed, and adjusted odds ratios (aOR) and 95% CIs were calculated.

RESULTS

A total of 1579 women were included, of whom 160 (10.1%) chose TOLAC, with 107 resulting in successful VBAC (67% successful TOLAC rate). The overall VBAC rate was 6.8%. Women who chose ERCS compared with those who chose TOLAC were more likely to be obese (aOR 3.20, 95% CI 1.85-5.54, P < 0.001), less likely to have had GA at delivery greater than 40 weeks (aOR 0.13, 95% CI 0.08-0.21, P < 0.001), less likely to have had a previous vaginal delivery (aOR 0.40, 95% CI 0.20-0.80, P < 0.001), and less likely to have had the previous CS for breech presentation (aOR 0.51, 95% CI 0.33-0.80, P = 0.003).

CONCLUSIONS

The overall TOLAC and VBAC rates in St. John's are low when compared with reported national rates. The successful TOLAC rate is within the expected range reported in the literature. Differences exist between women who chose ERCS compared with TOLAC.

Antenatal scoring system in predicting the success of planned vaginal birth following one previous caesarean section

This was a prospective observational study to determine the predictive factors for a successful vaginal birth after caesarean section (VBAC) and to develop a relevant antenatal scoring system. Patients with one previous caesarean section were included in this study. All data including maternal demographics, obstetric history, pregnancy progress and outcomes were collected and analysed. A total of 142 out of the 186 women (76.3%) had successful VBAC. History of previous vaginal delivery and non-recurrent indications for previous caesarean section were the significant predictive factors for a successful VBAC. Five variables for our scoring tool were selected. By using a proposed mean score of 4 out of 7, the scoring system had a sensitivity of 81.0%, specificity of 52.3% and a positive predictive value of 84.6%. VBAC antenatal scoring system was potentially a useful predictive tool in antenatal counselling. Impact statement What is already known on this subject: Planned vaginal birth after caesarean section (VBAC) is an important strategy to limit the overall caesarean section rate, which is related to maternal morbidities. However, trial of vaginal delivery does involve potential complications including scar dehiscence, postpartum haemorrhage and emergency hysterectomy. What the results of this study add: Clinical predictors of a successful VBAC include non-recurrent indications for the previous caesarean section, previous vaginal delivery, spontaneous onset of labour and birthweight less than 4kg. There were multiple screening tools developed to predict the likelihood of successful VBAC. These scoring systems involved various variables such as age, ethnicity, Bishop's score and previous caesarean indication. We had prospectively developed an antenatal scoring system based on five variables. Our result showed that patient with a score of four and above will have around 85% chance of successful VBAC. What the implications are of these findings for clinical practice and/or further research: We have also found that, estimated foetal weight based on ultrasound scan is a potential predictor for successful VBAC. This simple scoring method will be useful in-patient counselling regarding mode of delivery after one previous caesarean section. A multicentre study involving large cohort of patients is ideal to validate our scoring system.

Induction of labor by Foley catheter compared with spontaneous onset of labor after previous cesarean section: a cohort study

OBJECTIVE

To evaluate the safety of induction of labor (IOL) with Foley catheter (FC) in women with a history of previous cesarean section (CS) and to assess risk factors for repeat CS and adverse maternal outcomes.

STUDY DESIGN

Cohort study of 1559 women with a history of previous CS in Helsinki University Hospital, Finland between 2013 and 2014.

RESULTS

Three hundred and sixty-one women (23.2%) underwent IOL by FC and 1198 (76.8%) had spontaneous onset of labor. The rate of repeat CS was higher in women undergoing IOL (38% vs 20.2%; P<0.001). The overall rate of uterine rupture was 0.3% in induced labor and 0.8% in spontaneous onset of labor (P=0.47). Adverse maternal outcomes were not significantly different. The intrapartum and postpartum infection rates were higher in women undergoing IOL compared with spontaneous onset of labor (6.1% vs 1.8%; P>0.001 and 5.3% vs 1.3%; P<0.001, respectively).

CONCLUSION

FC appears safe and effective method for IOL in women with a history of previous CS.

Characterization of the myometrial transcriptome in women with an arrest of dilatation during labor

OBJECTIVE

The molecular basis of failure to progress in labor is poorly understood. This study was undertaken to characterize the myometrial transcriptome of patients with an arrest of dilatation (AODIL).

STUDY DESIGN

Human myometrium was prospectively collected from women in the following groups: (1) spontaneous term labor (TL; n=29) and (2) arrest of dilatation (AODIL; n=14). Gene expression was characterized using Illumina® HumanHT-12 microarrays. A moderated Student's t-test and false discovery rate adjustment were used for analysis. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) of selected genes was performed in an independent sample set. Pathway analysis was performed on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database using Pathway Analysis with Down-weighting of Overlapping Genes (PADOG). The MetaCore knowledge base was also searched for pathway analysis.

RESULTS

(1) Forty-two differentially expressed genes were identified in women with an AODIL; (2) gene ontology analysis indicated enrichment of biological processes, which included regulation of angiogenesis, response to hypoxia, inflammatory response, and chemokine-mediated signaling pathway. Enriched molecular functions included transcription repressor activity, heat shock protein (Hsp) 90 binding, and nitric oxide synthase (NOS) activity; (3) MetaCore analysis identified immune response chemokine (C-C motif) ligand 2 (CCL2) signaling, muscle contraction regulation of endothelial nitric oxide synthase (eNOS) activity in endothelial cells, and triiodothyronine and thyroxine signaling as significantly overrepresented (false discovery rate <0.05); (4) qRT-PCR confirmed the overexpression of Nitric oxide synthase 3 (NOS3); hypoxic ischemic factor 1A (HIF1A); Chemokine (C-C motif) ligand 2 (CCL2); angiopoietin-like 4 (ANGPTL4); ADAM metallopeptidase with thrombospondin type 1, motif 9 (ADAMTS9); G protein-coupled receptor 4 (GPR4); metallothionein 1A (MT1A); MT2A; and selectin E (SELE) in an AODIL.

CONCLUSION

The myometrium of women with AODIL has a stereotypic transcriptome profile. This disorder has been associated with a pattern of gene expression involved in muscle contraction, an inflammatory response, and hypoxia. This is the first comprehensive and unbiased examination of the molecular basis of an AODIL.

Delivery after prior cesarean: success rate and factors

Cesarean delivery rates in the United States have reached an all-time high. The current rate of 31% is 6 times higher than the 1970s rate. Many factors including physician preference and hospital accessibility account for this trend. A decreased vaginal birth after cesarean (VBAC) rate and an increased repeat cesarean rate have important consequences for women in future pregnancies. Because of these considerations, VBAC has been an important issue within the obstetric community for over 3 decades. Identifying the best candidates for VBAC using factors available to the obstetrician can increase the VBAC success rate while minimizing maternal morbidity.

Predictors of successful vaginal delivery after previous caesarean section in a Nigerian tertiary hospital

Achieving a successful vaginal birth after a previous caesarean section (VBAC) is an important strategy in reducing the rising rate of caesarean section and its associated morbidities. Records of 188 women attempting trial of vaginal delivery after a previous lower segment caesarean section were reviewed to predict factors favouring successful vaginal delivery. Of the 188 women, 64 had recurrent indications for caesarean section, while 124 had non-recurrent indications. The group with recurrent indications for previous caesarean section had less vaginal delivery and more repeat caesarean sections as compared with the group with non-recurrent indications (21.9% and 78.1% vs 46.8% and 53.2%, respectively, p = 0.01). Cephalopelvic disproportion was more frequent in the group with recurrent indications (65.6% vs 27.4%, p < 0.0001). Significant predictors of successful VBAC in this cohort of women were non-recurrent indications for the previous caesarean section (p < 0.001, odds ratio (95% CI) 0.32 (0.2-0.6)) and a previous vaginal delivery (p < 0.0001, odds ratio (95% CI) 3.90 (2.1-7.4)). A previous vaginal delivery and a non-recurrent indication for the previous caesarean section are important predictors of VBAC in this cohort of women.

Single- versus double-layer uterine incision closure and uterine rupture

OBJECTIVE

To evaluate whether closure of the uterine incision with one or two layers changes uterine rupture or vaginal birth after cesarean section (VBAC) success rates.

METHODS

Subjects with one previous cesarean section by documented transverse uterine incision that attempted VBAC were identified. Exclusion criteria included lack of documentation of the type of closure of the previous uterine incision, multiple gestation, more than one previous cesarean section, and previous scar other than low transverse. Uterine rupture and VBAC success rates were compared between those with single-layer and double-layer uterine closure. Time interval between deliveries, birth weight, body mass index (BMI), and history of previous VBAC were evaluated as possible confounders.

RESULTS

Of 948 subjects identified, 913 had double-layer closure and 35 had single-layer closure. The uterine rupture rate was significantly higher in the single-layer closure group (8.6% vs. 1.3%, p = 0.015). This finding persisted when controlling for previous VBAC, induction, birth weight >4000 g, delivery interval >19 months, and BMI >29 (OR 8.01, 95% CI 1.96-32.79). There was no difference in VBAC success rate (74.3% vs. 77%, p = 0.685).

CONCLUSION

Single-layer uterine closure may be more likely to result in uterine rupture.

Trial of labor after one cesarean: role of the order and number of prior vaginal births on the risk of emergency cesarean delivery and neonatal admission

OBJECTIVE

To evaluate the influences of mode of immediate preceding delivery and number of prior vaginal births on the risk of repeat cesarean and neonatal admission at attempted vaginal birth after cesarean.

MATERIALS AND METHODS

We performed a retrospective study of the risk factors for emergency repeat cesarean delivery and neonatal admission in a trial of labor after prior cesarean section. The study comprised 342 women at term with at least one prior vaginal delivery in addition to one previous lower transverse cesarean. Clinical variables with crude p < 0.2 on Fisher's exact test for the defined primary outcomes of repeat cesarean and neonatal admission were included in the model for multivariable logistic regression analysis.

RESULTS

Cesarean as the immediate preceding mode of delivery (adjusted odds ratio, 5.3; 95% confidence interval, 2.5-10.8) was an independent predictor of emergency repeat cesarean delivery but not of neonatal admission. Higher parity of two or more previous vaginal deliveries compared with only one prior vaginal delivery was not associated with repeat cesarean or neonatal admission.

CONCLUSION

In women who have had prior vaginal birth attempting a trial of labor after cesarean, a vaginal delivery before cesarean delivery is an independent risk factor for repeat cesarean. Women with two or more prior vaginal births have a similar risk for repeat cesarean and neonatal admission to women with only one prior vaginal birth.

Obesity in pregnancy: pre-conceptional to postpartum consequences

OBJECTIVE

To review the effects of obesity on reproduction and pregnancy outcome.

METHODS

A search of the literature was performed using key word searching and citation snowballing to identify English language articles published between January 1, 2000, and December 31, 2006, on the subject of obesity and its effects on pregnancy. Once the articles were identified, a thorough review of all results was conducted. Results and conclusions were compiled and summarized.

RESULTS

Obesity during pregnancy was linked with maternal complications ranging from effects on fertility to effects on delivery and in the postpartum period, as well as many complications affecting the fetus and newborn. The maternal complications associated with obesity included increased risks of infertility, hypertensive disorders, gestational diabetes mellitus, and delivery by Caesarean section. Fetal complications included increased risks of macrosomia, intrauterine fetal death and stillbirth, and admission to the neonatal intensive care unit.

CONCLUSION

Obesity causes significant complications for the mother and fetus. Interventions directed towards weight loss and prevention of excessive weight gain must begin in the pre-conception period. Obstetrical care providers must counsel their obese patients regarding the risks and complications conferred by obesity and the importance of weight loss. Maternal and fetal surveillance may need to be heightened during pregnancy; a multidisciplinary approach is useful. Women need to be informed about both maternal and fetal complications and about the measures that are necessary to optimize outcome, but the most important measure is to address the issue of weight prior to pregnancy.

Predicting Failure of a Vaginal Birth Attempt After Cesarean Delivery

OBJECTIVE

To identify a group of clinical factors that could be used to accurately predict failure in women attempting vaginal birth after cesarean (VBAC).

METHODS

We conducted a planned secondary analysis of a retrospective cohort study of women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. We collected information about maternal history and outcomes of the index pregnancy. We used univariable and multivariable statistical methods to develop a multivariable prediction model for the outcome of VBAC failure.

RESULTS

A total of 13,706 patients attempted VBAC, with a failure rate of 24.5%. Six variables were significantly associated with VBAC failure in our final logistic regression model: gestational age at delivery, maternal age, maternal race, labor type (spontaneous, augmented, or induced), history of vaginal delivery, and cephalopelvic disproportion or failed induction (combined variable) as prior cesarean indication. The area under the receiver operating characteristics curve is 0.717. To achieve a sensitivity of approximately 75%, a false-positive rate of approximately 40% would result.

CONCLUSION

Our results indicate that significant clinical variables (prelabor and labor) cannot reliably predict VBAC failure.

LEVEL OF EVIDENCE

II.

Vaginal birth after caesarean delivery: does maternal age affect safety and success?

To estimate maternal age effects on the rates of vaginal birth after caesarean delivery (VBAC), the related maternal complications and patient election to attempt VBAC, we conducted a secondary analysis of a retrospective cohort study of women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. We used bivariable and multivariable analyses to assess the association between maternal age and the study outcomes. A total of 25 005 patients were included, of whom 13 706 (54.81%) elected to attempt VBAC. After controlling for several confounding variables, using ages 21-34 years as the referent group, women aged 15-20 years were 27% less likely to have a failed VBAC attempt (OR = 0.73 [0.62, 0.87], P < 0.001). Analysing maternal age as a dichotomous variable, women who were of advanced maternal age (>or=35 years) were more likely to experience an unsuccessful trial of labour (OR = 1.14 [1.03, 1.25], P = 0.009). In addition, women >or=35 years of age had 39% more risk of experiencing one of the VBAC-related operative complications (OR = 1.39 [1.02, 1.89], P = 0.039). As women increase in age, they are less likely to attempt VBAC and more likely to have an unsuccessful labour trial. While teenage patients do not appear to be at increased risk for VBAC-related complications, patients of advanced maternal age do show an increase in composite VBAC-related operative complication rates.

Temporal trends in the rates of trial of labor in low-risk pregnancies and their impact on the rates and success of vaginal birth after cesarean delivery

OBJECTIVE

The national rate of vaginal birth after cesarean delivery decreased by 55% between 1996 and 2002. The objective of this investigation was to determine, in our population in upstate New York, whether this decline in the vaginal birth after cesarean delivery rate was due to temporal changes in the trial of labor rates or in the vaginal birth after cesarean delivery success rates.

STUDY DESIGN

Regional perinatal databases were used to obtain birth certificate data from a total of 135,833 live births in upstate New York from 1998 to 2002. Trial of labor, vaginal birth after cesarean delivery, and vaginal birth after cesarean delivery success rates were calculated for the 11,446 women who had had a previous cesarean delivery and a singleton, low-risk pregnancy at > or = 37 weeks of gestation. Additional factors that were analyzed included age, race, education, insurance, body mass index, parity, gestation, area of residence, prenatal care provider, size of hospital, and level of newborn nursery specialization. Tests for trends were conducted by year for each of the variables.

RESULTS

The trial of labor rate declined 39% from 58.7 in 1998 to 35.7 per 100 eligible women in 2002 (P < .01). The decline in trial of labor rates persisted after stratification within almost all groups (P < .01). The overall vaginal birth after cesarean delivery rate decreased 44%, from 42.7 in 1998 to 24.1 per 100 eligible women in 2002 (P < .01). The decline in vaginal birth after cesarean delivery rates persisted after stratification within almost all groups (P < .01). The rate of vaginal birth after cesarean delivery success was unchanged from 1998 to 2002 (P = not significant).

CONCLUSION

We found a major decline in trial of labor and vaginal birth after cesarean delivery rates in low-risk women from 1998 to 2002. There was no change in vaginal birth after cesarean delivery success in those patients who attempted trial of labor. This suggests that the decline in the vaginal birth after cesarean delivery rates that have been observed nationally may be due to a decline in trial of labor attempts and not to a change in vaginal birth after cesarean delivery success rates. The steep declines in trial of labor attempts and vaginal birth after cesarean deliveries suggest that there was a rapid change in the perception of optimal treatment practices for these patients by obstetricians.

How to promote, improve and test adherence to scientific evidence in clinical practice

BACKGROUND

Negative variation in the management of patients with the same clinical condition is frequent, and affects quality of care. Recent studies indicate that single interventions are not an effective solution. We aim to demonstrate that a multifaceted strategy can favor the introduction of research into practice, and to assess its long-term effects on a set of common medical conditions exhibiting significant negative variation at our institution.

METHODS

The strategy, devised and agreed upon by a multidisciplinary group, was first applied to one relevant medical condition--cerebral ischemic stroke. To test its effectiveness a quasi-experimental study was conducted, comparing an intervention group with historical controls. After validation the strategy was extended to other pathologies, and its long-term effect measured using evidence-based quality indicators. Adherence to each indicator was determined prospectively on a six-month basis for a period of at least two consecutive years. Measures are expressed as proportions with 95% confidence intervals.

RESULTS

Validation findings demonstrated that the strategy improved compliance with scientific evidence: the percentage of patients who received a CT scan within 24 hours of hospital presentation rose from 56% to 75%, (chi2 = 7.43 p < 0.01); admissions to selected wards increased from 45% to 64%, (chi2 = 7.81 p < 0.01); the number of physical medicine visits within 24 hours of the request grew from 59% to 91% (chi2 = 14,40 p < 0.001). Over a four-year period the program was gradually applied to 14 medical conditions. Except for 3 cases, compliance with the pathway, i.e. number of eligible patients for whom data on the care process is collected, was above the minimum requirement of 75%. Indicator adherence generally exhibited a positive trend, though variability was observed both among different conditions and between different semesters for the same pathology.

CONCLUSION

According to our experience, incorporation of research into practice can be favored by systematically applying a shared, multifaceted strategy, involving multidisciplinary teams supported by central coordination. Institutions should device a tailor-made approach, should train personnel on implementation strategies, and create cultural acceptance of change. Just like for experimental trials, human and economic resources should be allocated within health care services to allow the achievement of this objective.

Body mass index has a greater impact on pregnancy outcomes than gestational hyperglycaemia

AIMS/HYPOTHESIS

We evaluated diabetes-related pregnancy outcomes in a cohort of Spanish women in relation to their glucose tolerance status, prepregnancy BMI and other predictive variables.

METHODS

The present paper is part of a prospective study to evaluate the impact of American Diabetes Association (2000) criteria in the Spanish population. A total of 9,270 pregnant women were studied and categorised as follows according to prepregnancy BMI quartiles and glucose tolerance status: (1) negative screenees; (2) false-positive screenees; (3) gestational diabetes mellitus (GDM) according to American Diabetes Association criteria only; and (4) GDM according to National Diabetes Data Group criteria (NDDG). We evaluated fetal macrosomia, Caesarean section and seven secondary outcomes as diabetes-related pregnancy outcomes. The population-attributable and population-prevented fractions of predictor variables were calculated after binary logistic regression analysis with multiple predictors.

RESULTS

Both prepregnancy BMI and abnormal glucose tolerance categories were independent predictors of pregnancy outcomes. The upper quartile of BMI accounted for 23% of macrosomia, 9.4% of Caesarean section, 50% of pregnancy-induced hypertension and 17.6% of large-for-gestational-age newborns. In contrast, NDDG GDM accounted for 3.8% of macrosomia, 9.1% of pregnancy-induced hypertension and 3.4% of preterm births.

CONCLUSIONS/INTERPRETATION

In terms of population impact, prepregnancy maternal BMI exhibits a much stronger influence than abnormal blood glucose tolerance on macrosomia, Caesarean section, pregnancy-induced hypertension and large-for-gestational-age newborns.

Abnormalities of the First and Second Stages of Labor

Abnormalities of the first and second stages of labor refer for the most part to abnormal progression of labor. This article discusses the risk factors, diagnoses, management options, and outcomes of the various categories of labor abnormalities, and provides an evidence-based approach where one exists. The article concentrates on the term, healthy woman carrying a singleton, vertex, normally grown fetus with no anomalies.

Uterine rupture after induction of labour in women with previous caesarean section

BACKGROUND

The issues related to safety of induction of labour in women with previous caesarean section remain controversial. The main adverse outcome fuelling this debate is a "small" risk of uterine rupture that is potentially devastating for both the mother and the fetus.

OBJECTIVE

To estimate the risk of uterine rupture or dehiscence in women who require induction of labour with previous caesarean sections.

DESIGN

Five year retrospective review of computerised hospital records and case note review of index cases.

SETTING

Large inner city teaching hospital.

POPULATION

Two hundred and five women who had their labour induced with history of one lower segment caesarean section.

METHODS

This study was conducted at Liverpool Women's Hospital, a tertiary referral centre, with approximately 6000 births per annum. We searched the hospital's computerised records of deliveries from June 1997 to June 2002 and reviewed all indications and outcomes of induction of labour in women with one previous caesarean section. Women with singleton pregnancy and cephalic presentation were then divided into three groups: those with one previous caesarean section and no previous vaginal deliveries, those whose last delivery was a caesarean section but had delivered vaginally before and those whose last delivery was by vaginal route, but had had one caesarean section in the past.

MAIN OUTCOME MEASURES

Uterine rupture or dehiscence, adverse neonatal outcome.

RESULTS

Two hundred and five women were included. There were four cases of uterine rupture and one dehiscence (2.4%, 95% CI 0.8-5.6%). Two babies were profoundly acidotic at birth, but all five neonates were healthy when discharged from hospital with no long term morbidity. All five cases occurred in the group of women with no previous vaginal deliveries. The intrauterine pressure catheter recordings had contributed to the diagnosis of uterine rupture/dehiscence in three out of five cases.

CONCLUSION

In women with previous caesarean section and no vaginal deliveries, induction of labour carries a relatively high risk of uterine rupture/dehiscence despite all precautions, including intrauterine pressure monitoring.

The influence of obesity and diabetes on the risk of cesarean delivery

OBJECTIVE

To determine the influence of pregravid obesity and diabetes on cesarean delivery (CD) risk.

STUDY DESIGN

Women with singleton pregnancies of 23 weeks or more estimated gestational age who were undergoing a trial of labor January 1997 through June 2001 were categorized by pregravid body mass index (underweight [<19.8 kg/m 2 ], normal [19.8-25 kg/m 2 ], overweight [25.1-30 kg/m2], obese [>30 kg/m2]). Diabetes (DM) was divided into categories of gestational, treated with diet modification (A1GDM) or insulin (A2GDM), and pregestational (PDM). Prior CDs were excluded. CD rates for each group were compared in univariate analyses stratified by estimated gestational age (term, preterm, total). Other variables examined included DM, macrosomia (birth weight 4500 g or more), induction, and parity. Multiple regression included significant variables to predict the influence of diabetes and obesity on CD risk.

RESULTS

Records for 12,303 deliveries were evaluated (obese: 2828 [22.9%]; overweight: 2605 [21.2%]; A1GDM: 270 [2.2%]; A2GDM: 93 [0.8%]; PDM: 126 [1%]). Obese and overweight subjects had a higher risk for CD, compared with normal subjects (13.8% and 10.4% versus 7.7%, P < .0001 for each). Other CD risk factors were macrosomia (25% versus 9.4%), nulliparity (16.5% versus 4.7%), induction (17.4% versus 8.3%), diabetes (A1GDM: 16.7% versus 9.4%; A2GDM: 24.7% versus 9.5%; PDM: 34.9% versus 9.3%) and black race (10.7% versus 8.8%) ( P < .0001 for each). In multiple regression models including term deliveries, obesity and PDM were independent CD risk factors ([adjusted OR overweight: 1.5, P < .0001; adjusted OR PDM: 2.9, P = .01]; [adjusted OR obese: 2.4, P < .0001, PDM: 2.9, P = .0002]).

CONCLUSION

Pregravid obesity and diabetes independently increase the risk for CD. Given the disparate prevalence of obesity and diabetes in the United States, body habitus has a significantly larger impact on CD risk.

Effect of Prior Vaginal Delivery or Prior Vaginal Birth After Cesarean Delivery on Obstetric Outcomes in Women Undergoing Trial of Labor

OBJECTIVE

We sought to study the effects of prior vaginal delivery or prior vaginal birth after cesarean delivery (VBAC) on the success of a trial of labor after a cesarean delivery.

METHODS

An observational study of patients who underwent a trial of labor after a single low-transverse cesarean delivery. Patients with a previous cesarean delivery and no vaginal birth were compared with patients with a single vaginal delivery before or after the previous cesarean delivery. The rates of successful VBAC, uterine rupture, and scar dehiscence were analyzed. Multivariable regression was performed to adjust for confounding variables.

RESULTS

Of 2,204 patients, 1,685 (76.4%) had a previous cesarean delivery and no vaginal delivery, 198 (9.0%) had a vaginal delivery before the cesarean delivery, and 321 (14.6%) had a prior VBAC. The rate of successful trial of labor was 70.1%, 81.8%, and 93.1%, respectively (P <.001). A prior VBAC was associated with fewer third- and fourth-degree lacerations (8.5% versus 2.5% versus 3.7%, P <.001) and fewer operative vaginal deliveries (14.7% versus 5.6% versus 1.9%, P <.001) but not with uterine rupture (1.5% versus 0.5% versus 0.3%, P =.12). Patients with a prior VBAC had, in addition, a higher rate of uterine scar dehiscence (21.8%) compared with patients with a previous cesarean delivery and no vaginal delivery (5.3%; P =.001).

CONCLUSION

A prior vaginal delivery and, particularly, a prior VBAC are associated with a higher rate of successful trial of labor compared with patients with no prior vaginal delivery. In addition, prior VBAC is associated with an increased rate of uterine scar dehiscence.

Vaginal birth after caesarean section: clinical and legal perspectives

Vaginal birth after Caesarean section (VBAC) is currently the preferred method of delivery for pregnant women who have undergone 1 previous low transverse Caesarean section. This common practice warrants some reconsideration in light of recent clinical data on the risks associated with VBAC, and it is incumbent upon clinicians to ensure that women under their care are fully aware of these risks. Indeed, in some circumstances, an attempt at VBAC may be perceived by the courts to represent a negligent standard of care.