Detection and risk factors for preeclampsia.

Abstract

Throughout the world, preeclampsia is a leading cause of maternal mortality. In Mexico, it accounts for almost a third of maternal deaths. Research on epidemiology of preeclampsia is difficult because of differences in definition and inaccuracy in diagnosis. Several classification systems for hypertensive disorders of pregnancy have been proposed, however, evaluation of them is lacking. This dissertation aimed to estimate the prevalence of hypertensive disorders of pregnancy, to evaluate two main classification systems of hypertensive disorders of pregnancy proposed by the National High Blood Pressure Education Program (NHBPEP) and the Australasian Society for the Study of Hypertension in Pregnancy (ASSHP) with respect to maternal and fetal outcomes, and to compare both systems with clinical diagnoses. We then evaluated the association between a potential modifiable risk factor, physical activity, and hypertensive disorders of pregnancy. Finally, we identified socioeconomic factors associated with a particularly high risk. A cross-sectional study was conducted in among 3299 uninsured women delivering at the Hospital Infantil of Sonora, Mexico from September 2003 to March 2004. The ASSHP detected 15% more preeclamptic women than the NHBPEP (5.1% and 4.5% respectively). Both classification systems stratified women by probability of adverse maternal and fetal outcomes. Sensitivity of clinical diagnosis for preeclampsia, chronic hypertension and preeclampsia superimposed upon chronic hypertension was low (56.3%, 5.6% and 9.1% respectively). Increasing time spent in household activities was associated with decreasing risk of preeclampsia, (aOR=0.40, 95% CI: 0.20, 0.81 for more than 15 weekly hours). Women expending more than 17.5 METs per week in moderate activities also had a decreased risk for preeclampsia (aOR=0.44, 95% CI; 0.23, 0.85). Socially disadvantaged primiparous women had increased risk for preeclampsia, primiparas having low income (aOR=4.08, 95% CI; 2.24, 7.45), compared with women having high income and parity 2 or 3. Women with low income had also and increased risk to experience chronic hypertension (aOR=1.83, 95% CI; 1.02, 3.28). In conclusion, to reduce the mortality associated with preeclampsia, unifying medical criteria for preeclampsia diagnosis is required, while promotion of moderate physical activity and targeted public health interventions in high-risk primiparous women is needed.