Original Research Maternal Morbidity Associated With Early-Onset and Late-Onset Preeclampsia Sarka Lisonkova, MD, PhD, Yasser Sabr, MD, MHSc, Chantal Mayer, MD, Carmen Young, MD, Amanda Skoll, MD, and K.S. Joseph, MD, PhD OBJECTIVE: To examine temporal trends in early-onset compared with late-onset preeclampsia and associated severe maternal morbidity. METHODS: The study included all singleton deliveries in Washington State between 2000 and 2008 (N5670,120). Preeclampsia onset was determined using hospital records linked to birth certificates. Severe maternal mor- bidity was defined as any potentially life-threatening condition. Logistic regression was used to obtain adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). RESULTS: The preeclampsia rate was 3.0 per 100 single- ton births, and increased slightly from 2.9 to 3.1 between 2000 and 2008. Rates of early-onset and late-onset disease were 0.3% and 2.7%, respectively. The temporal increase was significant only for early-onset disease (4.5%/year; 95% CI 2.3–5.8%) after adjustment for changes in maternal characteristics. Maternal death rates were higher among women with early-onset (42.1/100,000 deliveries) and late-onset preeclampsia (11.2/100,000) compared with women without preeclampsia (4.2/100,000). The rate of severe maternal morbidity (excluding obstetric trauma) was 12.2 per 100 deliveries in the early-onset group (aOR 3.7, 95% CI 3.2–4.3), 5.5 per 100 deliveries in the late-onset group (aOR 1.7, 95% CI 1.6–1.9), and approxi- mately 3 per 100 in women without preeclampsia. Early- onset preeclampsia conferred a substantially higher risk of cardiovascular, respiratory, central nervous system, renal, hepatic, and other morbidity. However, rates of obstetric trauma were significantly lower among women with pre- eclampsia. CONCLUSION: Women with early-onset and late-onset preeclampsia have significantly higher rates of specific maternal morbidity compared with women without early-onset and late-onset disease. (Obstet Gynecol 2014;124:771–81) DOI: 10.1097/AOG.0000000000000472 LEVEL OF EVIDENCE: II P reeclampsia, typically characterized by elevated blood pressure and proteinuria after 20 weeks of pregnancy, is one of the leading causes of maternal– fetal morbidity and mortality. 1–10 In industrialized countries, the incidence of preeclampsia is approxi- mately 3–5 per 100 births. 4,11 Most industrialized countries have experienced a decline in the inci- dence of preeclampsia over the past decade, although isolated studies report a temporal increase in fre- quency. 12 Preeclampsia is a serious obstetric condition; in the United States, complications of preeclampsia account for up to 30% of maternal deaths during deliv- ery hospitalization. 6,10 Preeclampsia has been increasingly recognized as two different conditions: early-onset preeclampsia occurring at less than 34 weeks of gestation, and late-onset disease occurring at 34 or more weeks of gestation. 13–15 Early-onset and late-onset disease have different implications for the fetus and neonate, with an approximately 10-fold higher risk of perinatal death observed among mothers with early-onset dis- ease, and a twofold increased risk evident among From the Department of Obstetrics and Gynaecology and the School of Population and Public Health, University of British Columbia, and the Children’s & Women’s Hospital and Health Centre of British Columbia, Vancouver, British Columbia, and the Department of Obstetrics & Gynaecology, University of Alberta, Edmonton, Alberta, Canada; and the Department of Obstetrics and Gynaecology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. Drs. Lisonkova and Sabr are supported by a Canadian Institutes of Health Research Team grant in severe maternal morbidity (MAH-115445). Dr. Sabr is also supported by a new faculty award from the King Saud University, Saudi Arabia. Dr. Joseph holds a Canadian Institutes of Health Research Chair in maternal, fetal and infant health services research and his work is also supported by the Child and Family Research Institute. Corresponding author: Sarka Lisonkova, MD, PhD, Department of Obstetrics and Gynaecology, Women’s Hospital and Health Centre of British Columbia, Room C403, 4480 Oak Street, Vancouver, BC, Canada, V6H 3V4; e-mail: slisonkova@cfri.ca. Financial Disclosure The authors did not report any potential conflicts of interest. © 2014 by The American College of Obstetricians and Gynecologists. Published by Lippincott Williams & Wilkins. ISSN: 0029-7844/14 VOL. 124, NO. 4, OCTOBER 2014 OBSTETRICS & GYNECOLOGY 771