Association of Driving Distance to Maternity Hospitals and Maternal and Perinatal Outcomes.

OBJECTIVE

To assess whether there are associations between driving distance from the patient residence to the delivery hospital and adverse maternal and perinatal health outcomes.

METHODS

We performed a retrospective cohort study using 2011-2015 Pennsylvania birth records of live births at 20 weeks of gestation or more, excluding inpatient hospital transfers or implausible distances. The shortest driving distance from patient residence to the delivery hospital was calculated in ArcGIS and was evaluated in association with a composite of adverse maternal outcomes (blood transfusion, unplanned operation, ruptured uterus, unplanned hysterectomy, or intensive care unit admission) and neonatal intensive care unit (NICU) admission. Multivariable-adjusted Poisson models were used to estimate relative risks with 95% CIs with a referent difference of 1 km distance to the delivery hospital.

RESULTS

A total 662,245 birth records were included, and the median driving distance to the hospital was 11.3 km (interquartile range 5.4-21.6 km). The overall rate of the composite maternal outcome was 0.6% and of NICU admission was 8.4%. Compared with the referent distance, increasing driving distance was significantly associated with increased adjusted risks of the maternal composite outcome (adjusted relative risk [aRR] 1.22, 95% CI 1.07-1.36 for 60 km; aRR 1.36, 95% CI 1.19-1.53 for 70 km; and 1.53, 95% CI 1.31-1.75 for 80 km) and NICU admission (aRR 1.70, 95% CI 1.65-1.76 for 60 km; aRR 1.96, 95% CI 1.90-2.02 for 70 km; and aRR 2.25, 95% CI 2.18-2.33 for 80 km).

CONCLUSION

Longer distances to the delivery hospital were associated with greater risk of adverse maternal outcomes and NICU admission. Whether these findings reflect health care delivery deficits or simply serve as a marker of social deprivation requires further study.