RISK-FACTORS FOR PREECLAMPSIA IN HEALTHY NULLIPAROUS WOMEN - A PROSPECTIVE MULTICENTER STUDY

OBJECTIVE: We conducted a large clinical trial to evaluate the effect of low-dose aspirin on the frequency of preeclampsia in nulliparous wo men. A secondary objective of the trial was to identify those clinical characteristics that might be predictive for the development of preec lampsia. STUDY DESIGN: A total of 2947 healthy women with a single fet us were prospectively followed up from randomization at 13 to 27 weeks ' gestation to the end of pregnancy. Of these, 1465 women were assigne d to low-dose aspirin and 1482 to placebo. Baseline maternal blood pre ssure and demographic characteristics were examined for the prediction of preeclampsia. RESULTS: Preeclampsia developed in 156 women (5.3%). Four characteristics predicted the development of preeclampsia: in or der of importance, systolic blood pressure at entry, prepregnancy obes ity (weight as a percentage of desirable weight), number of previous a bortions or miscarriages, and smoking history. Contrary to previous re ports, black race was not a risk factor for preeclampsia. Systolic blo od pressure was a better predictor of preeclampsia than either diastol ic or mean arterial blood pressure. The greater the blood pressure or prepregnancy weight, the greater was the risk for preeclampsia. If the woman had never smoked or had never been previously pregnant, her ris k was also higher than average. A multivariate logistic regression equ ation based on these four factors was able to define a tenth of the po pulation at very high risk and another tenth at very low risk; the rat io of risk between these two groups was 12:1. The p value for each of the multivariate coefficients of the risk equation was systolic blood pressure (p < 0.001), prepregnancy weight (p < 0.01), smoking history (p < 0.01), and gravidity (p < 0.05). There were no statistically sign ificant differences in the predictive values of these risk factors bet ween women receiving low-dose aspirin or placebo. CONCLUSIONS: These r isk factors should be of value to practitioners counseling women regar ding preeclampsia. Moreover, such risk factors should be considered in the design of future studies dealing with preeclampsia.