Effect of Uterine Rupture on a Hospital's Future Rate of Vaginal Birth After Cesarean Delivery

Effects of maternal exposure to acute stress on birth outcomes: a quasi-experiment study

Numerous studies have shown associations between maternal stress and poor birth outcomes, but evidence is unclear for causal inference. Natural disasters provide an opportunity to study effects of quasi-randomized hardship with an accurate measure of onset and duration. In a population-based quasi-experimental study, we examined the effect of maternal exposure to the January 1998 Québec ice storm on birth outcomes by comparing pregnant mothers who lived in an area hard hit by the ice storm with those in two unaffected regions. In a total of 147,349 singleton births between 1995 and 2001, we used a difference-in-differences method to estimate the effects of the ice storm on gestational age at delivery (GA), preterm birth (PTB), weight-for-gestational-age z-scores (BWZ), large for gestational age (LGA), and small for gestational age (SGA). After adjusting for maternal and sociodemographic characteristics, there were no differences between the exposed and the unexposed mothers for birth outcomes. The estimated differences (exposed vs. unexposed) were 0.01 SDs (95% CI: -0.02, 0.05) for BWZ; 0.10% point (95% CI: -0.95%, 1.16%) for SGA; 0.25% point (95% CI: -0.78%, 1.28%) for LGA; -0.01 week (95% CI: -0.07, 0.05) for GA; and 0.16% point (95% CI: -0.66%, 0.97%) for PTB. Neither trimester-specific nor dose-response associations were observed. Overall, exposure to the 1998 Québec ice storm as a proxy for acute maternal stress in pregnancy was not associated with poor birth outcomes. Our results suggest that acute maternal hardship may not have a substantial effect on adverse birth outcomes.

Immunising' physicians against availability bias in diagnostic reasoning: a randomised controlled experiment

Background

Diagnostic errors have often been attributed to biases in physicians’ reasoning. Interventions to ‘immunise’ physicians against bias have focused on improving reasoning processes and have largely failed.

Objective

To investigate the effect of increasing physicians’ relevant knowledge on their susceptibility to availability bias.

Design, settings and participants

Three-phase multicentre randomised experiment with second-year internal medicine residents from eight teaching hospitals in Brazil.

Interventions

Immunisation: Physicians diagnosed one of two sets of vignettes (either diseases associated with chronic diarrhoea or with jaundice) and compared/contrasted alternative diagnoses with feedback. Biasing phase (1 week later): Physicians were biased towards either inflammatory bowel disease or viral hepatitis. Diagnostic performance test: All physicians diagnosed three vignettes resembling inflammatory bowel disease, three resembling hepatitis (however, all with different diagnoses). Physicians who increased their knowledge of either chronic diarrhoea or jaundice 1 week earlier were expected to resist the bias attempt.

Main outcome measurements

Diagnostic accuracy, measured by test score (range 0–1), computed for subjected-to-bias and not-subjected-to-bias vignettes diagnosed by immunised and not-immunised physicians.

Results

Ninety-one residents participated in the experiment. Diagnostic accuracy differed on subjected-to-bias vignettes, with immunised physicians performing better than non-immunised physicians (0.40 vs 0.24; difference in accuracy 0.16 (95% CI 0.05 to 0.27); p=0.004), but not on not-subjected-to-bias vignettes (0.36 vs 0.41; difference −0.05 (95% CI −0.17 to 0.08); p=0.45). Bias only hampered non-immunised physicians, who performed worse on subjected-to-bias than not-subjected-to-bias vignettes (difference −0.17 (95% CI −0.28 to −0.05); p=0.005); immunised physicians’ accuracy did not differ (p=0.56).

Conclusions

An intervention directed at increasing knowledge of clinical findings that discriminate between similar-looking diseases decreased physicians’ susceptibility to availability bias, reducing diagnostic errors, in a simulated setting. Future research needs to examine the degree to which the intervention benefits other disease clusters and performance in clinical practice.

Trial registration number

68745917.1.1001.0068.

Epidemiology of mental disorders during pregnancy and link to birth outcome: a large-scale retrospective observational database study including 38,000 pregnancies

PURPOSE

To investigate the real-life epidemiology of mental disorders during pregnancy and their impact on birth outcome in an unselected low-risk population in Germany.

METHODS

Claims data of the Techniker Krankenkasse (TK) were analyzed as part of a retrospective observational study over a one-year period from 01/2008 to 12/2008 including 38,174 pregnant women. ICD-10 codes were clustered into four diagnostic groups: depression, anxiety disorders, somatoform/dissociative disorders and acute stress reactions. The relationship between mental disorders, birth mode and infant weight was tested using chi-squared tests and multivariate logistic regression. Main outcome measures included the prevalence of mental disorders during pregnancy, performed cesarean sections and infants born underweight.

RESULTS

N = 16,639 cases with at least one diagnosis from the four mental disorder diagnostic groups were identified: 9.3% cases of depression, 16.9% cases with an anxiety disorder, 24.2% cases with a somatoform/dissociative disorder, and 11.7% cases of acute stress reactions. Women diagnosed with a mental disorder were more likely to deliver their child by cesarean section ([depression: OR =1.26 (95% CI 1.14-1.39); anxiety: OR 1.11 (95% CI 1.02-1.19); somatoform disorders: OR 1.12 (95% CI 1.05-1.20); acute stress reactions: OR 1.17 (95% CI 1.07-1.28)]. Furthermore, infants of women diagnosed with an ICD-10 code for depression during pregnancy were more likely to be underweight and/or delivered preterm [OR =1.34 (95% CI 1.06-1.69)].

CONCLUSIONS

We observed substantially high prevalence rates of mental disorders during pregnancy which urgently warrant more awareness for validated screening and adequate treatment options.

Teaching Critical Thinking: A Case for Instruction in Cognitive Biases to Reduce Diagnostic Errors and Improve Patient Safety

Diagnostic errors contribute to as many as 70% of medical errors. Prevention of diagnostic errors is more complex than building safety checks into health care systems; it requires an understanding of critical thinking, of clinical reasoning, and of the cognitive processes through which diagnoses are made. When a diagnostic error is recognized, it is imperative to identify where and how the mistake in clinical reasoning occurred. Cognitive biases may contribute to errors in clinical reasoning. By understanding how physicians make clinical decisions, and examining how errors due to cognitive biases occur, cognitive bias awareness training and debiasing strategies may be developed to decrease diagnostic errors and patient harm. Studies of the impact of teaching critical thinking skills have mixed results but are limited by methodological problems.This Perspective explores the role of clinical reasoning and cognitive bias in diagnostic error, as well as the effect of instruction in metacognitive skills on improvement of diagnostic accuracy for both learners and practitioners. Recent literature questioning whether teaching critical thinking skills increases diagnostic accuracy is critically examined, as are studies suggesting that metacognitive practices result in better patient care and outcomes. Instruction in metacognition, reflective practice, and cognitive bias awareness may help learners move toward adaptive expertise and help clinicians improve diagnostic accuracy. The authors argue that explicit instruction in metacognition in medical education, including awareness of cognitive biases, has the potential to reduce diagnostic errors and thus improve patient safety.

A conceptual framework for the impact of obesity on risk of cesarean delivery

Cesarean deliveries accounted for 32.2% of nearly 4 million births in the United States in 2014. Obesity affects a third of reproductive-age women and is associated with worse cesarean delivery outcomes. Studies have shown that increasing maternal body mass index correlates linearly with cesarean delivery rates, but little is known about the potential mediating and moderating mechanisms. Thus, a conceptual framework for understanding how obesity correlates with risk of cesarean delivery is crucial to determining safe ways to reduce the cesarean delivery rate among obese gravidas. Based on an extensive review and synthesis of the literature, we present a conceptual framework that posits how obesity may operate through several pathways to lead to a cesarean delivery. Our framework explores the complexity of obesity as an exposure that operates through potential mediating pathways, a moderator of cesarean delivery risk, and a covariate with other cesarean delivery risk factors. Among nulliparas, obesity appears to operate through 3 main proximal mediating mechanisms to increase risk of cesarean delivery including: (1) preexisting comorbidities and obstetric complications; (2) a slower progression of first-stage labor, potentially increasing the risk of cesarean delivery secondary to failure to progress; and (3) a prolongation of pregnancy, which is associated with risk of maternal postdates. For multiparas, a fourth proximal mediator of prior uterine scar may also increase cesarean delivery risk. Distal mediating mechanisms, which operate through one of the proximal mechanisms, may include an induction of labor or planned prelabor cesarean delivery. Obesity may also moderate the likelihood of cesarean delivery by interacting with clinician-level or hospital-level factors. Future research should assess the validity of this framework and seek to understand the relative contributions of each potential pathway between obesity and cesarean delivery. This will allow for evidence-based recommendations to reduce preventable cesareans among obese women by targeting modifiable mediators and moderators of the relationship between obesity and increased risk of cesarean delivery.

Risk factors and symptoms associated with maternal and neonatal complications in women with uterine rupture. A 16 years multicentric experience

OBJECTIVE

high maternal and fetal morbidity and mortality levels have been associated with uterine ruptures. The aims of our study were to determine risk factors and signs for maternal and fetal complications in patients with uterine rupture.

STUDY DESIGN

retrospective, population-based study, in all Val d'Oise public obstetrics departments, France, between 2000 and 2015. All patients with uterine rupture were analyzed using medical records. To identify risk factors and signs for maternal and fetal complications, patients were divided into two groups according to adverse maternal and fetal outcomes or not, and compared.

RESULTS

During the study period, 126 patients with complete uterine rupture were identified. In all, 74 (58.7%) had maternal and fetal complications, and these were more frequently observed in patients with unscarred uterus (N=18; p<0.001 and OR 5.52, 95% CI 2.09-14.55), lateral injured uterus (N=21; p<0.001), after labour induction (N=21, p=0.01 and OR 3.69, 95% CI 1.22-13.53), and when a sudden onset of abdominal pain, in patients with previous successful epidural analgesia, occurred (75.9% vs 39.2%, p<0.001 and OR 4.88, 95% CI 1.9-12.13).

CONCLUSION

Unscarred and lateral ruptures of uterus were associated with maternal vascular injuries, and higher maternal and fetal complications. Sudden onset of abdominal pain in woman with previous successful epidural analgesia might be predictive of complicated uterine rupture.

Utilizing Datasets to Advance Perinatal Research

Many organizations collect and make available perinatal data for research and quality improvement initiatives. Analysis of existing data and use of retrospective study design has many advantages for perinatal researchers. These advantages include large samples, inclusion of women from diverse groups, data reflective of actual clinical processes and outcomes, and decreased risk of direct maternal and fetal harm. We review 11 publicly available datasets relevant to perinatal research and quality improvement, detail the availability of interactive websites, and discuss strategies to locate additional datasets. While analysis of existing data has limitations, it may provide statistical power to study rare perinatal outcomes, support research applicable to diverse populations, and facilitate timely and ethical well-woman research immediately relevant to clinical care.

Association of Catastrophic Neonatal Outcomes With Increased Rate of Subsequent Cesarean Deliveries

OBJECTIVE

To evaluate whether full-term deliveries resulting in neonates diagnosed with hypoxic-ischemic encephalopathy are associated with a significant increase in the rate of subsequent unscheduled cesarean deliveries.

METHODS

We conducted a retrospective chart review study and examined all deliveries in the Department of Obstetrics and Gynecology at Hadassah University Hospital, Mt. Scopus campus, Jerusalem, Israel, during 2009-2014. We reviewed all cases of hypoxic-ischemic encephalopathy in singleton, term, liveborn neonates and identified seven such cases, three of which were attributed to obstetric mismanagement and four that were not. We measured the rate of unscheduled cesarean deliveries before and after the events and their respective hazard ratio.

RESULTS

Before a mismanaged delivery resulting in hypoxic-ischemic encephalopathy, the baseline rate of unscheduled cesarean deliveries was approximately 80 unscheduled cesarean deliveries for every 1,000 deliveries. In the first 4 weeks immediately after each of the three identified cases, there was a significant increase in the rate of unscheduled cesarean deliveries by an additional 48 unscheduled cesarean deliveries per 1,000 deliveries (95% confidence interval [CI] 27-70/1,000). This increase was transient and lasted approximately 4 weeks. We estimated that each case was associated with approximately 17 additional unscheduled cesarean deliveries (95% CI 8-27). There was no increase in the rate of unscheduled cesarean deliveries in cases of hypoxic-ischemic encephalopathy that were not associated with mismanagement.

CONCLUSION

The increase in the rate of unscheduled cesarean deliveries after a catastrophic neonatal outcome may result in short-term changes in obstetricians' risk evaluation.

Economic Evaluations Comparing a Trial of Labor with an Elective Repeat Cesarean Delivery: A Systematic Review

BACKGROUND

For women who have had a previous low transverse cesarean delivery, the decision to undergo a trial of labor after cesarean (TOLAC) or an elective repeat cesarean delivery (ERCD) has important clinical and economic ramifications.

OBJECTIVES

To evaluate the cost-effectiveness of the alternative choices of a TOLAC and an ERCD for women with low-risk, singleton gestation pregnancies.

METHODS

We searched EMBASE, MEDLINE, CINAHL, Cochrane Library, EconLit, and the Cost-Effectiveness Analysis Registry with no language, publication, or date restrictions up until October 2015. Studies were included if they were primary research, compared a TOLAC with an ERCD, and provided information on the relative cost of the alternatives. Abstracts and partial economic evaluations were excluded.

RESULTS

Of 310 studies initially reviewed, 7 studies were included in the systematic review. In the base-case analyses, 4 studies concluded that TOLAC was dominant over ERCD, 1 study found ERCD to be dominant, and 2 studies found that although TOLAC was more costly, it offered more benefits and was thus cost-effective from a population perspective when considering societal willingness to pay for better outcomes. In sensitivity analyses, cost-effectiveness was found to be dependent on a high likelihood of TOLAC success, low risk of uterine rupture, and low relative cost of TOLAC compared with ERCD.

CONCLUSIONS

For women who are likely to have a successful vaginal delivery, routine ERCD may result in excess morbidity and cost from a population perspective.

Trial of labor after cesarean in the low-risk obstetric population: a retrospective nationwide cohort study

OBJECTIVE

The purpose of this study was to evaluate the risk of adverse maternal outcomes associated with trial of labor (TOL) after cesarean during subsequent pregnancies in the low-risk population.

STUDY DESIGN

We conducted a retrospective cohort study using the Nationwide Inpatient Sample and ICD-9 diagnostic and procedure codes from the years 2003 to 2011. A cohort of low-risk pregnant women with a history of previous cesarean delivery were identified and separated into two groups: TOL and no TOL. Logistic regression analysis was used to calculate odds ratios (ORs) comparing adverse maternal outcomes between these two groups.

RESULTS

Out of 7 290 474 registered deliveries, there were 685 137 low-risk women who met inclusion criteria. Of these women, 144 066 (21.0%) underwent a TOL, with rates remaining steady over the course of our study. The TOL group was at increased risk of overall morbidity (OR 1.74, 95% confidence interval (CI), 1.66-1.79), most notably uterine rupture (OR 22.52, 95% CI, 19.35-26.20, P<0.01). A secondary analysis showed no apparent correlation between TOL and concomitant adverse maternal outcomes in cases of uterine rupture.

CONCLUSION

Although these outcomes remain rare, low-risk women undergoing a TOL remain at increased risk of adverse maternal events as compared with those who chose elective repeat cesarean delivery.