Influence of time of delivery on risk of adverse neonatal outcome in different size of delivery units: a retrospective cohort study in Finland

Busy day effect on adverse obstetric outcomes using a nationwide ecosystem approach: Cross-sectional register study of 601 247 hospital deliveries

OBJECTIVE

To study the busy day effect on selected neonatal adverse outcomes in different sized delivery hospitals and in the entire nationwide obstetric ecosystem.

DESIGN

A cross-sectional register study.

SETTING

The lowest and highest 10% of the daily delivery volume distribution were defined as quiet and busy days, respectively. The days between (80%) were defined as optimal delivery volume days. The differences in the incidence of selected adverse neonatal outcome measures were analysed between busy versus optimal days and quiet versus optimal days at the hospital category and for the entire obstetric ecosystem level.

POPULATION

A total of 601 247 singleton hospital deliveries between 2006 and 2016, occurred in non-tertiary (C1-C4, stratified by size) and tertiary level (C5) delivery hospitals.

METHODS

Analyses were performed by the methods of the regression analyses with crude and adjusted odds ratios including 99% CI.

MAIN OUTCOME MEASURES

Birth asphyxia.

RESULTS

At the ecosystem level, adjusted odds ratio for birth asphyxia was 0.81 (99% CI 0.76-0.87) on busy versus optimal days. Breakdown to hospital categories show that adjusted odds ratios for asphyxia on busy versus optimal days in non-tertiary hospitals (C3, C4) were 0.25 (99% CI 0.16-0.41) and 0.17 (99% CI 0.13-0.22), respectively, and in tertiary hospitals was 1.20 (99% CI 1.10-1.32).

CONCLUSIONS

Busy day effect as a stress test caused no extra cases of neonatal adverse outcomes at the ecosystem level. However, in non-tertiary hospitals busy days were associated with a lower and in tertiary hospitals a higher incidence of neonatal adverse outcomes.

Are birth outcomes in low risk birth cohorts related to hospital birth volumes? A systematic review

Background

There is convincing evidence that birth in hospitals with high birth volumes increases the chance of healthy survival in high-risk infants. However, it is unclear whether this is true also for low risk infants. The aim of this systematic review was to analyze effects of hospital’s birth volume on mortality, mode of delivery, readmissions, complications and subsequent developmental delays in all births or predefined low risk birth cohorts. The search strategy included EMBASE and Medline supplemented by citing and cited literature of included studies and expert panel highlighting additional literature, published between January/2000 and February/2020. We included studies which were published in English or German language reporting effects of birth volumes on mortality in term or all births in countries with neonatal mortality < 5/1000. We undertook a double-independent title-abstract- and full-text screening and extraction of study characteristics, critical appraisal and outcomes in a qualitative evidence synthesis.

Results

13 retrospective studies with mostly acceptable quality were included. Heterogeneous volume-thresholds, risk adjustments, outcomes and populations hindered a meta-analysis. Qualitatively, four of six studies reported significantly higher perinatal mortality in lower birth volume hospitals. Volume-outcome effects on neonatal mortality (n = 7), stillbirths (n = 3), maternal mortality (n = 1), caesarean sections (n = 2), maternal (n = 1) and neonatal complications (n = 1) were inconclusive.

Conclusion

Analyzed studies indicate higher rates of perinatal mortality for low risk birth in hospitals with low birth volumes. Due to heterogeneity of studies, data synthesis was complicated and a meta-analysis was not possible. Therefore international core outcome sets should be defined and implemented in perinatal registries.

Systematic review registration

PROSPERO: CRD42018095289

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03988-y.