Pregnancy-associated hospitalizations in the United States in 1991 and 1992: A comprehensive view of maternal morbidity

OBJECTIVE: Our purpose was to update the national estimate of severe pregnancy complications and describe associated maternal characteristics of hospitalizations during pregnancy, applying an expanded definition of maternal morbidity. STUDY DESIGN: From 1991 and 1992 National Hospital Discharge Survey data, we estimated ratios of hospitalizations per 100 deliveries and compared relative ratios by maternal characteristics. We computed standard errors with the SUDAAN program and estimated 95% confidence intervals for relative ratios. RESULTS: The likelihood of hospitalization for pregnancy complications appeared to decline between the period 1986 and 1987 and the period 1991 and 1992, although primarily for pregnancy loss hospitalizations. In 1991 and 1992 there were 18.0 total pregnancy-associated hospitalizations/100 births (17.2 for whites, 28.1 for blacks). Component ratios were 12.3 for obstetric hospitalizations, 4.4 for pregnancy loss hospitalizations, and 1.4 for nonobstetric hospitalizations; all ratios were higher for blacks than for whites. CONCLUSIONS: Maternal hospitalization remains a substantial component of prenatal care. Because of underreporting and changes in medical practice, recent declines in maternal hospitalization may not represent true reductions in maternal morbidity.