Clinical implications of the study
A high proportion of placental dysfunction related stillbirths can potentially be prevented by a three stage strategy. First, screening for preeclampsia at 11-13 weeks’ gestation and treatment of the high-risk group by aspirin; this is effective in the prevention of preterm preeclampsia but also in the prevention of early SGA in the absence of preeclampsia 25-30. Second, screening during the routine mid-trimester scan by a combination of maternal risk factors, EFW and UtA-PI, which identifies a high-risk group that contains a high proportion of placental dysfunction related stillbirths that occur at 24-37 weeks’ gestation; close monitoring of these pregnancies for early diagnosis of SGA fetuses could prevent at least some of such stillbirths by defining the best approach to monitoring and best timing of delivery. The detection rate of stillbirths is higher when UtA-PI is included in the model in addition to maternal risk factors and EFW, highlighting the necessity of including this measurement in the routine mid-trimester scan; it is easy for competent sonographers to learn this technique and it only adds about 2 minutes to the examination. Third, routine ultrasound examination at 36 weeks’ gestation, because screening at mid-gestation provides poor prediction of stillbirth at term; more effective screening for late SGA can be achieved by screening at 3631,32.