Abstract / Summary
The pathophysiology of preeclampsia remains unclear. The identification of risk factors and protective factors may help elucidate the pathophysiologic basis of preeclampsia and improve its prediction. A cross-sectional survey of all deliveries in 39 hospitals across 14 provinces in mainland China from January 1 to December 31, 2011 was conducted to evaluate risk factors and protective factors for preeclampsia. The incidence rate of preeclampsia was 3.7% (4137/110, 926). Multivariate logistic analysis revealed advanced maternal age (aOR=2.058; 95% CI: (1.894–2.235)), chronic hypertension (aOR=8.391; 95% CI: (7.352–9.576)], obesity (aOR=3.761; 95% CI: (3.487–4.056)), GDM/DM (aOR=1.656 (1.479–1.855)), multiple pregnancies (aOR=1.491; 95% CI: (1.283–1.735)), anemia (aOR=1.253; 95% CI: (1.110–1.414)) and blood type AB (aOR=1.134; 95% CI: (1.006–1.279)) as independent risk factors. The protective factors included placenta previa (aOR=0.401; 95% CI: 0.296–0.543) and blood type A (aOR=0.901; 95% CI: 0.829–0.980). The prevalence of obstetric complications associated with preeclampsia was higher, including preterm birth [aOR=8.542; 95% CI: (7.985–9.137)], FGR [aOR= 5.020; 95% CI: (4.635–5.437)], placental abruption [aOR=3.453; 95% CI: (2.777–4.293)] and oligohydramnios [aOR=1.520; 95% CI: (1.306–1.768)]. The results revealed that chronic hypertension and obesity were more strongly associated with early-onset preeclampsia; whereas multiple gestation, maternal age, GDM/DM, and anemia were more strongly associated with late-onset preeclampsia. Placenta previa was a protective factor against preeclampsia (PE), particularly early-onset PE. Early-onset PE was more likely to cause placental abruption, FGR and oligohydramnios than late-onset PE. Our study revealed different epidemiological features between early-onset and late-onset PE, suggesting the involvement of different mechanisms, which requires further research.