Medline ® Abstracts for References 4,5
of 'Preeclampsia: Clinical features and diagnosis'
Epidemiology of pre-eclampsia and the other hypertensive disorders of pregnancy.
Hutcheon JA, Lisonkova S, Joseph KS
Best Pract Res Clin Obstet Gynaecol. 2011 Aug;25(4):391-403. Epub 2011 Feb 18.
Hypertensive disorders of pregnancy include chronic hypertension, gestational hypertension, pre-eclampsia and chronic hypertension with superimposed pre-eclampsia. Pre-eclampsia complicates about 3% of pregnancies, and all hypertensive disorders affect about five to 10% of pregnancies. Secular increases in chronic hypertension, gestational hypertension and pre-eclampsia have occurred as a result of changes in maternal characteristics (such as maternal age and pre-pregnancy weight), whereas declines in eclampsia have followed widespread antenatal care and use of prophylactic treatments (such as magnesium sulphate). Determinants of pre-eclampsia rates include a bewildering array of risk and protective factors, including familial factors, sperm exposure, maternal smoking, pre-existing medical conditions (such as hypertension, diabetes mellitus and anti-phospholipid syndrome), and miscellaneous ones such as plurality, older maternal age and obesity. Hypertensive disorders are associated with higher rates of maternal, fetal and infant mortality, and severe morbidity, especially in cases of severe pre-eclampsia, eclampsia and haemolysis, elevated liver enzymes and low platelets syndrome.
Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, Canada. email@example.com
Pre-eclampsia rates in the United States, 1980-2010: age-period-cohort analysis.
Ananth CV, Keyes KM, Wapner RJ
OBJECTIVE: To estimate the contributions of biological aging, historical trends, and birth cohort effects on trends in pre-eclampsia in the United States.
DESIGN: Population based retrospective study.
SETTING: National hospital discharge survey datasets, 1980-2010, United States.
PARTICIPANTS: 120 million women admitted to hospital for delivery.
MAIN OUTCOME MEASURES: Temporal changes in rates of mild and severe pre-eclampsia in relation to maternal age, year of delivery, and birth cohorts. Poisson regression as well as multilevel age-period-cohort models with adjustment for obesity and smoking were incorporated.
RESULTS: The rate of pre-eclampsia was 3.4%. The age-period-cohort analysis showed a strong age effect, with women at the extremes of maternal age having the greatest risk of pre-eclampsia. In comparison with women delivering in 1980, those delivering in 2003 were at 6.7-fold (95% confidence interval 5.6-fold to 8.0-fold) increased risk of severe pre-eclampsia. Period effects declined after 2003. Trends for severe pre-eclampsia also showed a modest birth cohort effect, with women born in the 1970s at increased risk. Compared with women born in 1955, the risk ratio for women born in 1970 was 1.2 (95% confidence interval 1.1 to 1.3). Similar patterns were also evident for mild pre-eclampsia, although attenuated. Changes in the population prevalence of obesity and smoking were associated with period and cohort trends in pre-eclampsia but did not explain the trends.
CONCLUSIONS: Rates of severe pre-eclampsia have been increasing in the United States and age-period-cohort effects all contribute to these trends. Although smoking and obesity have driven these trends, changes in the diagnostic criteria may have also contributed to the age-period-cohort effects. Health consequences of rising obesity rates in the United States underscore that efforts to reduce obesity may be beneficial to maternal and perinatal health.
Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, 622 West 168th Street, New York, NY 10032, USA.