Objective::To determine the incidence of preeclampsia (PE) and preterm PE in Spain and to identify the risk factors for developing the disease.Methods::This is a multicenter prospective cohort study performed at six maternity units across Spain. Women with singleton pregnancies attending their first-trimester routine visit at the hospital were offered participation. Maternal and pregnancy characteristics, including mean arterial pressure, as well as ultrasound findings were recorded. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for subsequent development of PE.Results::A total of 5868 pregnancies were recruited for this study, including 174 (3.0%) cases of PE, 47 (0.8%) cases of preterm PE and 127 (2.2%) cases of term PE. Median maternal age was 33.9 years (interquartile range: 30.1 to 36.9) and median gestational age at the routine visit was 12.7 weeks (interquartile range: 12.3 to 13.0). However, 293 (5.0%) of the women were on aspirin treatment during pregnancy, likely reducing the true incidence of the disease. As expected, increasing body mass index (n P < 0.001), uterine artery pulsatility index ( n P= 0.011) and mean arterial pressure (n P < 0.001), assisted conception ( n P= 0.013), previous personal (n P < 0.001) or family history of PE ( n P= 0.024) and chronic hypertension (n P= 0.001) were identified as independent risk factors for developing subsequent PE during pregnancy. Screening for PE by maternal factors alone leads to a detection rate of 36.8% (64/174) at 10.0% (587/5868) screen positive rate.n Conclusion::In Spain, 3.0% of singleton pregnancies are complicated by PE and 0.8% require delivery before term due to its severity. Screening of PE by risk factors alone is only able to detect about 40% of total PE at 10% screen-positive rate.“,”Objective::To determine the incidence of preeclampsia (PE) and preterm PE in Spain and to identify the risk factors for developing the disease.Methods::This is a multicenter prospective cohort study performed at six maternity units across Spain. Women with singleton pregnancies attending their first-trimester routine visit at the hospital were offered participation. Maternal and pregnancy characteristics, including mean arterial pressure, as well as ultrasound findings were recorded. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for subsequent development of PE.Results::A total of 5868 pregnancies were recruited for this study, including 174 (3.0%) cases of PE, 47 (0.8%) cases of preterm PE and 127 (2.2%) cases of term PE. Median maternal age was 33.9 years (interquartile range: 30.1 to 36.9) and median gestational age at the routine visit was 12.7 weeks (interquartile range: 12.3 to 13.0). However, 293 (5.0%) of the women were on aspirin treatment during pregnancy, likely reducing the true incidence of the disease. As expected, increasing body mass index (n P < 0.001), uterine artery pulsatility index ( n P= 0.011) and mean arterial pressure (n P < 0.001), assisted conception ( n P= 0.013), previous personal (n P < 0.001) or family history of PE ( n P= 0.024) and chronic hypertension (n P= 0.001) were identified as independent risk factors for developing subsequent PE during pregnancy. Screening for PE by maternal factors alone leads to a detection rate of 36.8% (64/174) at 10.0% (587/5868) screen positive rate.n Conclusion::In Spain, 3.0% of singleton pregnancies are complicated by PE and 0.8% require delivery before term due to its severity. Screening of PE by risk factors alone is only able to detect about 40% of total PE at 10% screen-positive rate.