Trends in Maternal Morbidity Before and During Pregnancy in California

Objectives. We examined trends in maternal comorbidities in California. Methods. We conducted a retrospective cohort study of 1 551 017 California births using state-linked vital statistics and hospital discharge cohort data for 1999, 2002, and 2005. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify the following conditions, some of which were preexisting: maternal hypertension, diabetes, asthma, thyroid disorders, obesity, mental health conditions, substance abuse, and tobacco use. We estimated prevalence rates with hierarchical logistic regression models, adjusting for demographic shifts, and also examined racial/ethnic disparities. Results. The prevalence of these comorbidities increased over time for hospital admissions associated with childbirth, suggesting that pregnant women are getting sicker. Racial/ethnic disparities were also significant. In 2005, maternal hypertension affected more than 10% of all births to non-Hispanic Black mothers; maternal diabetes affected nearly 10% of births to Asian/Pacific Islander mothers (10% and 43% increases, respectively, since 1999). Chronic hypertension, diabetes, obesity, mental health conditions, and tobacco use among Native American women showed the largest increases. Conclusions. The prevalence of maternal comorbidities before and during pregnancy has risen substantially in California and demonstrates racial/ethnic disparity independent of demographic shifts.