Association between morbidity among term newborns and low-risk caesarean delivery rates.

OBJECTIVE: To examine the association between county-level caesarean delivery (CD) rates among women at low risk and morbidity among term newborns. DESIGN: Cross-sectional study. SETTING: Population-based study of US county-level birth data from 2015 to 2017. POPULATION: Nulliparous women with term, singleton, vertex-presenting infants (NTSV) at low risk for morbidity. METHODS: The primary exposure was county-level CD rates. MAIN OUTCOME MEASURES: The outcome was morbidity among the low-risk NTSV cohort, categorised as severe (5-minute Apgar score of ≤3, assisted ventilation for ≥6 hours, severe neurologic injury or seizure, transfer or death) or moderate (5-minute Apgar score of <7 but >3, administration of antibiotics or assisted ventilation at delivery). We used linear regression models to determine the association between county NTSV CD and neonatal morbidity rates with cluster robust standard errors. RESULTS: The analysis included data from 2 753 522 births in 952 counties from all 48 states. The mean NTSV CD rate was 23.6% (standard deviation 4.8%). The median severe and moderate neonatal morbidity rates were 15.2 (interquartile range, IQR 9.4-23.6) and 52.5 (IQR 33.4-75.7) per 1000 births, respectively. In the unadjusted analysis using the risk-adjusted exposure and outcome, every percentage point increase in the CD rate of a county was associated with 0.6 (95% CI -0.9, -0.3) and 2.3 fewer (95% CI -3.4, -1.1) cases of severe and moderate neonatal morbidity per 1000 live births. After adjustment for other county factors, the relationships remained significant. These findings were tested in multiple sensitivity analyses. CONCLUSIONS: Lower county-level NTSV CD rates were associated with a small increase in morbidity among term newborns in the USA. TWEETABLE ABSTRACT: Lower county-level caesarean delivery rates were associated with an increase in morbidity among term newborns in the USA.

Hospital volume and cesarean delivery among low-risk women in a nationwide sample.

OBJECTIVE: We sought to determine if hospital delivery volume was associated with a patient's risk for cesarean delivery in low-risk women. STUDY DESIGN: This study retrospectively examines a cohort of 1 657 495 deliveries identified in the 2013 Nationwide Readmissions Database. Hospitals were stratified by delivery volume quartiles. Low-risk patients were identified using the Society for Maternal-Fetal Medicine definition (n=845 056). A multivariable logistic regression accounting for hospital-level clustering was constructed to assess the factors affecting a patient's odds for cesarean delivery. RESULTS: The range of cesarean delivery rates was 2.4-51.2% among low-risk patients, and the median was 16.5% (IQR 12.8-20.5%). The cesarean delivery rate was higher in the top two-volume-quartile hospitals (17.4 and 18.2%) compared to the bottom quartiles (16.4 and 16.3%) (P<0.001). Hospital volume was not associated with a patient's odds for cesarean delivery after adjusting for patient and other hospital characteristics (P=0.188). CONCLUSION: Hospital delivery volume is not an independent predictor of cesarean delivery in this population.

The relationship between the rising cesarean delivery and postpartum readmission rates.

OBJECTIVE: This study seeks to determine if the increasing rate of postpartum readmissions is related to the increasing rate of cesarean delivery. STUDY DESIGN: Readmitted patients were identified in the State Inpatient Databases of California, Florida and New York from 2004 to 2011. Relevant maternal comorbidities, pregnancy complications and intrapartum events were collected using ICD-9 diagnosis and procedure codes. The effects of cesarean delivery were first examined via univariate logistic regression to calculate the odds of readmission by year for patients who had delivered via cesarean section. Then, we used multivariate logistic regression models to isolate the effect of mode of delivery on the odds of readmission by adjusting for the effects of patient demographics, hospital characteristics and maternal comorbidities. RESULTS: Nearly one million deliveries were identified each year, and ~600 000 deliveries per year met inclusion criteria. During this time, the readmission rate increased from 1.72 to 2.16%, and the cesarean delivery rate increased from 30.4 to 33.9%. The odds of readmission for patients delivered via cesarean section decreased yearly, from 1.343 (95% CI: 1.295 to 1.392) in 2004 to 1.046 (95% CI: 1.012 to 1.108) in 2011. In a multivariate model, the odds based on year were 1.032 (95% CI: 1.030 to 1.035), demonstrating an increased odds of readmission over time. When cesarean delivery was added to the model, this odds estimate did not change (OR: 1.031, 95% CI: 1.028 to 1.035), suggesting it did not account for the increased odds of readmission over time, even though cesarean delivery rates increased. However, when maternal comorbidities were added to the model, the odds ratio for year became insignificant (OR: 1.001, 95% CI: 0.998 to 1.005), suggesting that they accounted for the increasing rate of readmissions. CONCLUSIONS: The increasing cesarean delivery rate does not explain the increasing rate of postpartum readmissions. Rather, the increasing postpartum readmission rate appears to be related to maternal comorbidities.

Relationship between parity and brachial plexus injuries.

OBJECTIVE: Few characteristics have been identified as risk factors for brachial plexus injuries. We sought to investigate a potential relationship with multiparity based on clinical observation at our institution. STUDY DESIGN: In this retrospective case series, we analyzed all brachial plexus injuries recognized at or after delivery between October 2003 and March 2013 (n=78) at a single academic medical institution. Patient, infant, labor and delivery characteristics were compared for women with and without prior vaginal deliveries. RESULT: Of the 78 injuries, 71 (91%) occurred after a vaginal delivery and 7 (9%) after a cesarean delivery. Of the 71 injuries after a vaginal delivery, 58% occurred in women with a prior vaginal delivery (n=41, 5.7 per 10 000 live births) compared with 42% without a prior vaginal delivery (n=30, 4.0 per 10 000 live births). Multiparous patients had shorter labor courses and fewer labor interventions than nulliparous patients. Providers clinically underestimated the birth weights to a greater extent in multiparas than in nulliparas (median underestimation 590 vs 139 g, P=0.0016). The median birth weight was 4060 g in the multiparous group, which was significantly larger than affected infants born to the nulliparous group (3591 g, P=0.006). The affected infants of the multiparous group were, as expected, significantly larger than their previously born siblings (median 567 g larger, P<0.001). CONCLUSION: Brachial plexus injuries occurred as frequently in multiparous patients as in nulliparous patients. In general, multiparous patients are more likely to have larger infants; however, providers significantly underestimate the birth weight of their infants. The findings of this study should deter providers from assuming that a prior vaginal delivery is protective against brachial plexus injuries.