Midwife annual delivery workload and maternal and neonatal adverse
outcomes, is there an association?
Objective: To evaluate the association between certified nurse midwife
(CNM) annual delivery workload and short-term, adverse maternal and
neonatal outcomes occurring in vaginal deliveries. Design: A
retrospective cohort study Setting: A single tertiary academic center.
Population: All single, live vertex term vaginal deliveries between 2006
and 2018 were included Methods: deliveries were categorized into two
groups based on the CNM median annual volume of deliveries during the
study duration. The “high-volume” and “low-volume” groups included
deliveries above and below the median annual delivery volume,
respectively as a dichotomous variable. Further analyses were performed
for the annual volume by deciles. Main outcomes measures: Short term
maternal and neonatal outcomes were compared between “high-volume” and
“low-volume” groups and between deciles. Results: During the study
period 140,856 deliveries met the study criteria. The median annual
deliveries of a single CNM was 152 [114-195]. Maternal and labor
characteristics were comparable between the groups. Maternal outcomes
were not significantly associated with the CNM’s annual workload.
However, neonates delivered by CNMs with “low” annual volume had
higher a higher rate of neonatal jaundice (aOR 1.07, 95% CI
[1.00-1.14]) and mechanical ventilation (aOR 1.32, 95% CI
[1.05-1.66). Conclusion: Adverse perinatal outcomes are only mildly
affected by CNM’s annual volume after controlling for the CNM,
parturient and neonate’s characteristics. Funding: This study was not
funded by any organization.