The Fetal Medicine Foundation has funded and coordinated several major multicentre randomized trials to investigate the potential value of interventions in the prevention of preeclampsia, preterm birth and macrosomia. The studies demonstrated that:

• Aspirin (150 mg/day) started from 12 weeks of gestation can substantially reduce the risk of preterm preeclampsia
• Aspirin started at 23 weeks does not reduce the risk of preeclampsia
• Progesterone (200 mg each night) in women with short cervix can substantially reduce the risk of preterm birth
• Cervical cerclage in women with short cervix does not reduce the risk of preterm birth
• Cervical pessary in women with short cervix does not reduce the risk of preterm birth
• Metformin in obese women does not reduce the risk of macrosomia but it reduces the risk of preeclamsia.