An analysis of antenatal hospitalization in Canada, 1991-2003

Objectives: To examine the incidence and temporal trends of hospitalization during pregnancy, and provide additional information on maternal morbidity among Canadian women. Methods: A population-based cohort study was conducted using the Canadian Institute for Health Information's Discharge Abstract Database between fiscal year 1991/92 and 2002/03. This database included antenatal hospitalizations for all hospital deliveries (N =3,103,365) in Canada except for those occurring in Manitoba and Quebec. Temporal trends, and variations in the non-delivery antenatal hospitalization ratio (per 100 deliveries) by maternal age and province or territory were quantified. Primary causes for antenatal hospitalization, the lengths of in-hospital stay, and changing pattern by maternal age and time period were compared. Results: The overall antenatal hospitalization ratio declined by 43%, from 24.0 per 100 deliveries in 1991/92 to 13.6 in 2002/03. Younger women tended to be hospitalized more frequently than older women: 27.1 per 100 deliveries for women aged less than 20 years and 21.5 per 100 deliveries for 20-24 years, respectively, compared to 11.5 per 100 for women aged 35-39 years. The antenatal hospitalization ratio varied greatly by province/territory - from 12.2 per 100 deliveries in Ontario to 30.7 in the Yukon. Threatened preterm labour, antenatal hemorrhage, hypertensive disorders, severe vomiting and diabetes remained the five most common causes for antenatal hospitalization, although the trends for the first four declined dramatically from 1991/92 to 2002/03. Younger women were more likely to be admitted for threatened preterm labour and severe vomiting, while older women were more likely to be admitted for antenatal hemorrhage and hypertensive disorders. Conclusions: The decline in antenatal hospitalization may reflect changes in management of pregnancy complications, e.g., transition from in-hospital care to out-of-hospital care, and introduction of antepartum home care programs. Information on interprovincial/territorial variations in antenatal hospitalization may be helpful in directing future maternal health care.