Intrauterine growth retardation (IUGR) is a major risk factor for perinatal mortality and morbidity. Thus, there is a compelling need to introduce sensitive measures to detect IUGR fetuses. Routine third trimester ultrasonography is increasingly used to detect IUGR. However, we lack evidence for its clinical effectiveness. This pragmatic nationwide stepped wedge cluster-randomized trial examines the (cost-)effectiveness of routine third trimester ultrasonography in reducing severe adverse perinatal outcome through perinatal protocolized management.

For this trial (the IRIS study), more than 13.000 Dutch women with a singleton pregnancy receiving care in 60 participating primary care midwifery practices were included at 22 weeks’ gestation from February 1st 2015 to February 29th 2016. In the intervention and control group fetal growth was monitored by serial fundal height assessments. All practices started offering the control condition (ultrasonography based on medical indication). Every three months, 20 practices were randomized to the intervention condition, i.e. apart from ultrasonography if indicated, two routine ultrasound examinations were performed (at 28-30 weeks and 34-36 weeks). Data on perinatal outcomes were retrieved from the Dutch Perinatal Registry (PERINED) and collected from hospital records by research assistants for cases with an indication to have a possible severe perinatal outcome.

Secondary psychosocial and child neurodevelopmental outcomes included pre- and postpartum anxiety, depression, bonding, and quality of life and offspring behavioral and cognitive functioning. These secondary outcomes were collected via maternal report using validated instruments within a prospective sub-study among almost 2000 mothers and their children followed from 22 weeks’ gestation until toddlerhood.

PI: Dr. Ank de Jonge

Amsterdam UMC
Vrije Universiteit
Department of Midwifery Science
AVAG-Amsterdam Public Health
Van der Boechhorststraat 7
1081 HV Amsterdam, The Netherlands


Verfaille, V., De Jonge, A., Mokkink, L., Westerneng, M., Van der Horst, H., Jellema, P., Franx, A. (2017). Multidisciplinary consensus on screening for, diagnosis and management of fetal growth restriction in the Netherlands. BMC Pregnancy and Childbirth, 16 October,

Henrichs, J., Verfaille, V., Viester, L., Westerneng, M., Molewijk, B., Franx, A., de Jonge A. J. & The IRIS study group (2016). Effectiveness and cost-effectiveness of routine third trimester ultrasound screening for intrauterine growth restriction: study protocol of a nationwide stepped wedge cluster-randomized trial in The Netherlands (The IRIS Study). BMC Pregnancy and Childbirth, 16, 310.

Website: IRIS project