Temporal Trends in Chorioamnionitis by Maternal Race/Ethnicity and Gestational Age (1995–2010)

Abstract

Objective. To characterize trends in chorioamnionitis (CAM) by maternal race/ethnicity and gestational age. Study Design. We examined trends in CAM from 1995–2010 among singleton births in all Kaiser Permanente Southern California hospitals (). Data were extracted from Perinatal Service System and clinical utilization records. Gestational age- and race/ethnicity-specific biannual diagnosis rates were estimated using the Poisson regression after adjusting for potential confounding factors. Results. Overall diagnosis rates of CAM increased from 2.7% in 1995-1996 to 6.0% in 2009-2010 with a relative increase of 126% (95% confidence intervals [CI] 113%–149%). From 1995-1996 to 2009-2010, CAM increased among the Whites (1.8% to 4.3%, -value for trend <.001), Blacks (2.2% to 3.7%, -value for trend <.001), Hispanics (2.4% to 5.8%, -value for trend <.001), and Asian/Pacific Islanders (3.6% to 9.0%, -value for trend <.001). The adjusted relative percentage change in CAM from 1995-1996 to 2009-2010 was for Whites [preterm 21% (9%–78%), term 138% (108%–173%)], for Blacks [preterm 24% (−9%–81%), term 62% (30%–101%)], for Hispanics [preterm 31% (3%–66%), term 135% (114%–159%)], and for Asian/Pacific Islanders [preterm 44% (9%–127%), term 145% (109%–188%)]. Conclusion. The findings suggest that CAM diagnosis rate has increased for all race/ethnic groups. This increase is primarily due to increased diagnosis at term gestation.