First-Trimester Screening for Preeclampsia

Abstract

Preeclampsia is the leading cause of maternal and fetal morbidity and mortality internationally, affecting approximately 2% to 5% of pregnancies.1 This pregnancy-specific syndrome generally develops after the 20th week of gestation, and is characterized by hypertension, edema, and proteinuria. Hemolysis, thrombocytopenia, and seizures may occur in more serious cases, and stroke, kidney, and multiorgan failure can lead to major maternal morbidity or death in the most severe cases. At the same time, reduced placental blood flow can lead to fetal growth restriction, prematurity, and fetal morbidity and mortality. The definitive treatment of preeclampsia is delivery. The signs, symptoms, and major risks of preeclampsia usually improve or even resolve within hours after the placenta has been removed. However, preeclampsia often develops many weeks before the mother’s due date, when immediate delivery is undesirable. If the baby must be delivered prematurely due to deteriorating maternal condition, the typical challenges associated with prematurity are exacerbated by chronic fetal insults associated with preeclampsia. Severe preeclampsia requiring delivery before 34 weeks’ gestation, also referred to as early-onset preeclampsia, occurs in approximately 0.5% of pregnancies.2 Medically indicated premature delivery as a result of severe preeclampsia is responsible for 15% of preterm births in the United States.3 In view of the potentially dramatic impact of preeclampsia, it is incumbent on all obstetricians to be aware of new data that may help in the diagnosis and/or treatment of this condition. Because research in this field is moving so quickly, there is a gap in the knowledge of many practitioners in this regard. The goal of this lesson is to update practitioners on emerging data regarding the development of preeclampsia prediction models so that they will be prepared to expeditiously introduce these models into their clinical practice once verified as effective.