Universal screening for foetal growth restriction.

Foetal growth restriction (FGR) is a major cause of morbidity and mortality. Clinical methods for identifying women whose pregnancies are affected by FGR do not perform well. Despite this, the current approach to screening includes the clinical assessment of risk and targeted use of ultrasound. Universal screening of women using ultrasound has not been shown to improve outcomes in randomised controlled trials and, when implemented nationally in France, appeared mostly to change outcomes for the worse through the effect of iatrogenic prematurity on false positives. Research is currently focused on the development of screening tests with higher sensitivity and specificity, for example, by combining ultrasound with placental biomarkers. The diagnostic tests employed should be identified through high-quality research that investigates the diagnostic accuracy of the tests, and this will usually involve blinding of the results. Therefore, future trials of screening and intervention will require careful planning. Moreover, if trials are to be powered for perinatal death, large sample sizes will be required