Objective To derive national rates of severe maternal morbidity diagnosed during hospitalisation for delivery in Ireland.

Study Design Retrospective cohort study of 330,955 women admitted to hospital for delivery between 2005 and 2009. Using validated diagnostic criteria from Australia, we examined hospital discharge records (ICD-10-AM) to identify likely cases of severe maternal morbidity. We derived overall and category-specific morbidity incidence rates and examined five-year trends. Unadjusted relative risks were computed to assess sociodemographic and obstetric factors associated with morbidity status.

Results The severe maternal morbidity five-year incidence rate was 14.2 per 1,000 deliveries. Between 2005 and 2009, the overall rate of severe morbidity significantly increased from 14.0 to 16.4 cases per 1,000 deliveries (test for trend p-value <0.001). The most frequently diagnosed severe morbidity indicators were blood transfusion (112.6 per 10,000 deliveries), evacuation of haematoma (7.2 per 10,000 deliveries), and dilation and curettage with general anaesthesia (3.9 per 10,000 deliveries). The risk of severe morbidity was more than three-fold (RR 3.34; 95% CI: 2.95-3.79) among women carrying multiple gestations and more than four-fold (RR 4.14; 95% CI: 3.47-4.94) among women with a stillbirth. Further, severe morbidity risk was 43% higher among women with a pre-existing condition (RR 1.43; CI 1.21-1.69).

Conclusion Overall rates of severe morbidity were similar between Ireland and Australia, though disparities in specific morbidities were identified. The ability to directly compare morbidity rates is advantageous, underscoring the need for a uniform definition of severe morbidity to promote accurate and reliable international comparisons.