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International Journal of Reproductive Medicine
Volume 2013, Article ID 906467, 6 pages
Research Article

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

1Division of Maternal-Fetal Medicine, Department of Obstetrics-Gynecology, West Los Angeles Kaiser Permanente Southern California Medical Group, Los Angeles, CA 90034, USA
2Division of Maternal-Fetal Medicine, Department of Obstetrics-Gynecology, University of California, Irvine, CA 92868, USA
3Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA 91101, USA
4Department of Obstetrics and Gynecology, University of Medicine and Dentistry New Jersey, New Brunswick, NJ 08901, USA

Received 28 December 2012; Accepted 3 March 2013

Academic Editor: Yuping Wang

Copyright © 2013 Michael J. Fassett et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.