Effect of severity of illness on cesarean delivery rates in Washington State

Interventions to decrease complications after shoulder dystocia: a systematic review and Bayesian meta-analysis

OBJECTIVE

This study aimed to evaluate the outcomes associated with the implementation of simulation exercises to reduce the sequela of shoulder dystocia.

DATA SOURCES

Electronic databases (Ovid MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature database, and Scopus) were initially queried in June 2020 and updated in November 2020. The following 3 concepts were introduced and refined using the controlled vocabulary of the database: vaginal birth, shoulder dystocia, and simulation training. There were no limitations to the year of publication as part of the search strategy.

STUDY ELIGIBILITY CRITERIA

We included all studies that reported on the frequency of shoulder dystocia and the associated complications before and after the implementation of interventional exercises to improve outcomes.

METHODS

Two authors independently assessed the abstracts and full-text articles of all studies for eligibility and evaluated the quality of the included studies using the Newcastle-Ottawa Scale. Any inconsistencies related to study evaluation or data extraction were resolved by a third author. The coprimary outcomes of this systematic review and meta-analysis were neonatal brachial plexus palsy diagnosed following deliveries complicated by shoulder dystocia and persistence of brachial palsy at 12 months or later. The secondary outcomes were the frequency of shoulder dystocia and cesarean delivery. Study effects were combined using a Bayesian meta-analysis and were reported as risk ratios and 95% credible intervals (Crs).

RESULTS

Of the 372 articles reviewed, 16 publications, which included 428,552 deliveries with 217,713 (50.8%) deliveries during the preintervention and 210,839 (49.2%) deliveries during the postinterventional period, were included in the meta-analysis. The incidence of neonatal brachial plexus palsy after shoulder dystocia decreased from 12.1% to 5.7% (risk ratio, 0.37; 95% Cr, 0.26-0.57; probability of reduction 100%). The overall proportion of neonatal brachial plexus palsy decreased, but with less precision, from 0.3% to 0.1% (risk ratio, 0.53; 95% Cr, 0.21-1.26; probability of reduction 94%). Two studies followed newborns with brachial plexus palsy for at least 12 months. One study that reported on persistent neonatal brachial plexus palsy at 12 months among 1148 shoulder dystocia cases noted a reduction in persistent neonatal brachial plexus palsy from 1.9% to 0.2% of shoulder dystocia cases (risk ratio, 0.13; 95% confidence interval, 0.04-0.49). In contrast, the study that reported on persistent neonatal brachial plexus palsy at 12 months for all deliveries noted that it did not change significantly, namely from 0.3 to 0.2 per 1000 births (risk ratio, 0.77; 95% confidence interval, 0.31-1.90). Following the implementation of shoulder dystocia interventional exercises, the diagnosis of shoulder dystocia increased significantly from 1.2% to 1.7% of vaginal deliveries (risk ratio, 1.39; 95% Cr, 1.19-1.65; probability of increase 100%). Compared with the preimplementation period, the cesarean delivery rate increased postimplementation from 21.2% to 25.9% (risk ratio, 1.22; 95% Cr, 0.93-1.59; probability of increase 93%). We created an online tool (https://ccrebm-bell.shinyapps.io/sdmeta/) that permits calculation of the absolute risk reduction and absolute risk increase attributable to the intervention vis-à-vis the incidence of shoulder dystocia, neonatal brachial plexus palsy, and cesarean deliveries.

CONCLUSION

Introduction of shoulder dystocia interventional exercises decreased the rate of neonatal brachial plexus palsy per shoulder dystocia case; the data on persistence of neonatal brachial plexus palsy beyond 12 months is limited and contradictory. Implementation of the interventions was associated with an increase in the diagnosis of shoulder dystocia and rate of cesarean deliveries.

Population risk factors for nulliparous, term, singleton, vertex caesarean birth: a national cross-sectional study

OBJECTIVE

To characterise medical, obstetric and demographic risk factors associated with nulliparous, term, singleton, vertex (NTSV) caesarean birth.

STUDY DESIGN

Cross-sectional study.

SETTING

United States delivery hospitalisations.

POPULATION

NTSV births in 2016-18 US natality data.

METHODS

This study analysed a national sample of natality data generated by the United States National Vital Statistics System. NTSV deliveries were identified. The primary outcome was caesarean birth. Risk factors including maternal age, body mass index (BMI) and pregestational diabetes were analysed. Multivariable log-linear regression models analysed factors associated with NTSV caesarean with adjusted risk ratios (aRR) as measures of effect.

RESULTS

Of 11 622 400 deliveries, 3 764 707 met NTSV criteria, and their caesarean section rate was 25.9%. Maternal age 35-39 years (aRR 1.51, 95% CI 1.50-1.52) and 40-54 years (aRR 2.03, 95% 2.00-2.05) compared with age 19-34 years; BMI 25 to <30 kg/m2 (aRR 1.32, 95% CI 1.31-1.33), 30 to <35 kg/m2 (aRR 1.57 95% CI 1.56-1.58), 35 to <40 kg/m2 (aRR 1.82, 95% CI 1.80-1.83) and ≥40 kg/m2 (aRR 2.17, 95% CI 2.15-2.19) compared with BMI 18.5-24.9 kg/m2; and pregestational diabetes (aRR 1.54, 95% CI 1.51-1.57) were all associated with increased risk. Risk factors allowed stratification of patients into high-risk versus low-risk groups. The NTSV caesarean rate was 37.9% in women who had one or more of the following characteristics: age ≥35 years, BMI ≥30 kg/m2 or pregestational diabetes. In comparison, the NTSV caesarean rate was 20.8% among women without any of these three risk factors (P < 0.01).

CONCLUSION

Among NTSV births, BMI, maternal age and medical conditions are important risk factors for caesarean delivery.