Inter-facility travel time and referral for emergency obstetric care in the 15 most populated cities of Nigeria: a spatial analysis

Abstract

BACKGROUND: Timely access to comprehensive emergency obstetric care (CEmOC) can be vital for ensuring maternal and newborn survival. However, pregnant women in need of CEmOC may not initially present at a CEmOC facility, thereby necessitating inter-facility referral. We assessed inter-facility travel time between potential referring non-CEmOC facilities and receiving CEmOC facilities in the 15 largest Nigerian cities. METHODS: S2 cell to their respective nearest CEmOC facilities. Geographic coordinates of non-CEmOC facilities were mapped to S2 cells to retrieve travel time to public CEmOC facilities. Travel times were estimated from each S2 cell to the nearest CEmOC facilities by ownership (public and private) under peak traffic scenario (weekdays 18-20 h) and off-peak traffic scenario (weekends 01-03 h). Based on the shortest inter-facility travel time, each non-CEmOC facility was paired with a public CEmOC facility. Median travel time and percentage of non-CEmOC facilities located > 30 and > 60 min to the nearest public CEmOC facility were estimated. Sensitivity analysis comparing the API's travel time estimates for randomly-selected 10% of non-CEmOC facilities with those from other methods was conducted. RESULTS: Altogether, 4,563 and 1,963 non-CEmOC and CEmOC facilities were included, respectively. Percentage of non-CEmOC facilities located > 30 min to the nearest public CEmOC was highest in Port Harcourt (51%) and lowest in Maiduguri (6%). All non-CEmOC facilities were located ≤ 60 min from the nearest public CEmOC facility in Aba, Owerri, and Ilorin. Median number of non-CEmOC facilities connected to a public CEmOC facility was 27, with five public CEmOC facilities connected to > 100 non-CEmOC facilities. For some non-CEmOC facilities, the nearest public CEmOC facilities are in a contiguous city or state. CONCLUSIONS: Inter-facility referrals in large Nigerian cities show substantial variation in travel time and uneven referral loads, revealing critical pressure points that may delay timely access to CEmOC. Integrating travel time metrics into maternal health planning is essential for improving the efficiency, equity, and resilience of resource-constrained urban referral systems.