Fig. 2

The stepped wedge design of the IRIS study. Pregnant women will be enrolled during months 1–12 at 20–22 weeks of gestation. All midwifery practices (n = 60) will start with the control condition providing care as usual. At intervals of 3 months, a third of all practices will change status from the control to the intervention condition, which means providing routine third trimester ultrasound screening at 28–30 weeks and 34–36 weeks of gestation. Postnatal follow-up will be conducted in months 18–42