Objective

To evaluate whether a standardized approach to identify pregnant women at risk for shoulder dystocia (SD) is associated with reduced incidence of SD and brachial plexus injury (BPI).

Methods

Between 2011 and 2015, prospective data were collected from 29 community-based hospitals in the USA during implementation of an evidence-based practice bundle, including an admission risk assessment, required "timeout" before operative vaginal delivery (OVD), and low-fidelity SD drills. All women with singleton vertex pregnancies admitted for vaginal delivery were included. Rates of SD, BPI, OVD, and cesarean delivery were compared between a baseline period (January 2011-September 2013) and an intervention period (October 2013-June 2015), during which there was a system-wide average bundle compliance of 90%.

Results

There was a significant reduction in the incidence of SD (17.6%; P=0.028), BPI (28.6%; P=0.018), and OVD (18.0%; P<0.001) after implementation of the evidence-based practice bundle. There was a nonsignificant reduction in primary (P=0.823) and total (P=0.396) cesarean rates, but no association between SD drills and incidence of BPI.

Conclusion

Implementation of a standard evidence-based practice bundle was found to be associated with a significant reduction in the incidence of SD and BPI. Utilization of low-fidelity drills was not associated with a reduction in BPI.

Objective

This study aimed to evaluate the incidence of brachial plexus birth injury (BPBI) and its associations with maternal demographic factors. Additionally, we sought to determine whether longitudinal changes in BPBI incidence differed by maternal demographics.

Study design

We conducted a retrospective cohort study of over 8 million maternal-infant pairs using California's Office of Statewide Health Planning and Development Linked Birth Files from 1991 to 2012. Descriptive statistics were used to determine BPBI incidence and the prevalence of maternal demographic factors (race, ethnicity, age). Multivariable logistic regression was used to determine associations of year, maternal race, ethnicity, and age with BPBI. Excess population-level risk associated with these characteristics was determined by calculating population attributable fractions.

Results

The incidence of BPBI between 1991 and 2012 was 1.28 per 1,000 live births, with peak incidence of 1.84 per 1,000 in 1998 and low of 0.9 per 1,000 in 2008. Incidence varied by demographic group, with infants of Black (1.78 per 1,000) and Hispanic (1.34 per 1,000) mothers having higher incidences compared with White (1.25 per 1,000), Asian (0.8 per 1,000), Native American (1.29 per 1,000), other race (1.35 per 1,000), and non-Hispanic (1.15 per 1,000) mothers. After controlling for delivery method, macrosomia, shoulder dystocia, and year, infants of Black (adjusted odds ratio [AOR] = 1.88, 95% confidence interval [CI] = 1.70, 2.08), Hispanic (AOR = 1.25, 95% CI = 1.18, 1.32), and advanced-age mothers (AOR = 1.16, 95% CI = 1.09, 1.25) were at increased risk. Disparities in risk experienced by Black, Hispanic, and advanced-age mothers contributed to a 5, 10, and 2% excess risk at the population level, respectively. Longitudinal trends in incidence did not vary among demographic groups. Population-level changes in maternal demographics did not explain changes in incidence over time.

Conclusion

Although BPBI incidence has decreased in California, demographic disparities exist. Infants of Black, Hispanic, and advanced-age mothers are at increased BPBI risk compared with White, non-Hispanic, and younger mothers.

Key points

· The incidence of BPBI has decreased over time.. · Demographic disparities in BPBI incidence and risk exist.. · Infants of Black, Hispanic, and advanced age mothers are at greatest risk of BPBI..

Objective

To evaluate the association of maternal delivery history with a brachial plexus birth injury risk in subsequent deliveries and to estimate the effect of subsequent delivery method on brachial plexus birth injury risk.

Methods

We conducted a retrospective cohort study of all live-birth deliveries occurring in California-licensed hospitals from 1996 to 2012. The primary outcome was recurrent brachial plexus birth injury in a subsequent pregnancy. The exposure was delivery history (parity, shoulder dystocia in a previous delivery, or previously delivering a neonate with brachial plexus birth injury). Multiple logistic regression was used to model adjusted associations of delivery history with brachial plexus birth injury in a subsequent pregnancy. The adjusted risk and adjusted risk difference for brachial plexus birth injury between vaginal and cesarean deliveries in subsequent pregnancies were determined, stratified by delivery history, and the number of cesarean deliveries needed to prevent one brachial plexus birth injury was determined.

Results

Of 6,286,324 neonates delivered by 4,104,825 individuals, 7,762 (0.12%) were diagnosed with a brachial plexus birth injury. Higher parity was associated with a 5.7% decrease in brachial plexus birth injury risk with each subsequent delivery (adjusted odds ratio [aOR] 0.94, 95% CI 0.92-0.97). Shoulder dystocia or brachial plexus birth injury in a previous delivery was associated with fivefold (0.58% vs 0.11%, aOR 5.39, 95% CI 4.10-7.08) and 17-fold (1.58% vs 0.11%, aOR 17.22, 95% CI 13.31-22.27) increases in brachial plexus birth injury risk, respectively. Among individuals with a history of delivering a neonate with a brachial plexus birth injury, cesarean delivery was associated with a 73.0% decrease in brachial plexus birth injury risk (0.60% vs 2.21%, aOR 0.27, 95% CI 0.13-0.55) compared with an 87.9% decrease in brachial plexus birth injury risk (0.02% vs 0.15%, aOR 0.12, 95% CI 0.10-0.15) in individuals without this history. Among individuals with a history of brachial plexus birth injury, 48.1 cesarean deliveries are needed to prevent one brachial plexus birth injury.

Conclusions

Parity, previous shoulder dystocia, and previously delivering a neonate with brachial plexus birth injury are associated with future brachial plexus birth injury risk. These factors are identifiable prenatally and can inform discussions with pregnant individuals regarding brachial plexus birth injury risk and planned mode of delivery.

Objective

Twins account for approximately 1 in 30 live births in the United States. However, there are limited clinical experience studies published in noninvasive prenatal testing (NIPT) for detecting aneuploidies in twins. This study reports the performance of an SNP-based NIPT in the largest cohort with known outcomes for high-risk aneuploidy results.

Method

This is a retrospective analysis of 18,984 results from commercial single-nucleotide polymorphism (SNP)-based NIPT tests performed in twins between October 2, 2017 and December 31, 2019. Follow-up for all 211 high-risk cases was solicited.

Results

Follow-up outcomes were obtained in 105 cases. Positive predictive values (PPVs) for high-risk results were 88.7% (63/71, 95% Confidence Interval [CI]: 79.0%-95.0%) for trisomy 21% and 72.7% (8/11, 95% CI: 39.0%-94.0%) for trisomy 18. The results were stratified into monozygotic (MZ) and dizygotic (DZ). The PPVs in MZ were 100% for both trisomy 21 (4/4, 95% CI: 40%-100%) and trisomy 18 (1/1, 95% CI: 2.5%-100%). No trisomy 13 cases were detected in the MZ group. The PPVs in DZ were 88.1% (59/67, 95% CI: 77.8%-94.7%), 70.0% (7/10, 95% CI: 34.8%-93.3%), and 66.7% (2/3, 95% CI: 9.4%-99.2%) for trisomy 21, trisomy 18, and trisomy 13, respectively.

Conclusion

The performance of SNP-based NIPT in this large twin cohort was comparable to previously reported twin NIPT studies. SNP-based NIPT allows for zygosity-based PPV assessment.

We analyzed maternal plasma cell-free DNA samples from twin pregnancies in a prospective blinded study to validate a single-nucleotide polymorphism (SNP)-based non-invasive prenatal test (NIPT) for zygosity, fetal sex, and aneuploidy. Zygosity was evaluated by looking for either one or two fetal genome complements, fetal sex was evaluated by evaluating Y-chromosome loci, and aneuploidy was assessed through SNP ratios. Zygosity was correctly predicted in 100% of cases (93/93; 95% confidence interval (CI) 96.1%-100%). Individual fetal sex for both twins was also called with 100% accuracy (102/102; 95% weighted CI 95.2%-100%). All cases with copy number truth were also correctly identified. The dizygotic aneuploidy sensitivity was 100% (10/10; 95% CI 69.2%-100%), and overall specificity was 100% (96/96; 95% weighted CI, 94.8%-100%). The mean fetal fraction (FF) of monozygotic twins (n = 43) was 13.0% (standard deviation (SD), 4.5%); for dizygotic twins (n = 79), the mean lower FF was 6.5% (SD, 3.1%) and the mean higher FF was 8.1% (SD, 3.5%). We conclude SNP-based NIPT for zygosity is of value when chorionicity is uncertain or anomalies are identified. Zygosity, fetal sex, and aneuploidy are complementary evaluations that can be carried out on the same specimen as early as 9 weeks' gestation.