ObjectiveTo compute ratios of severe pregnancy complications (the number of hospitalizations for pregnancy complications per 100 deliveries) and to examine factors associated with their prevalence.MethodsUsing population-based California hospital discharge data to estimate hospitalization ratios of pregnancy complications during 1987--1992, we defined cases by preselected pregnancy complication codes from the InternationalClassification of Diseases, Ninth Revision, Clinical Modification, excluding induced abortions and delivery-associated complications. All hospital deliveries of liveborn or stillborn infants were included in our denominator. We examined ratios by age, race-ethnicity, payment source, total hospitalization charges, and length of hospital stay.ResultsThere were 833,264 hospitalizations for pregnancy complications in California (25 complications per 100 deliveries), which included admissions for preterm labor (33%), genitourinary infection (16%), and pregnancy-induced hypertension (15%). Age-specific ratios were highest for women 14 years old and younger (38 per 100 deliveries) and lowest for women 25--29 years old (23 per 100 deliveries). Ratios of complications varied by race-ethnicity; black women had the highest (42 per 100 deliveries), and Asian-Pacific Islander women had the lowest (21 per 100 deliveries). Ratios were unaffected by payment source. In 1987, Medicaid charges were $118 million for 33% of the number of total hospitalizations for complications. In 1992, such Medicaid hospitalizations accounted for $356 million (49%) of the $734 million in total charges and for 183,295 (45%) of the 409,000 total hospital days.ConclusionOur results showed disparities in ratios of severe complications of pregnancy by age and race-ethnicity as well as a shift of financial burden to Medicaid. These findings suggest that such complications may be reduced by identifying risk factors and targeting high-risk groups.