Advances in obstetrical ultrasound technology, combined with newer magnetic resonance imaging (MRI) methods, cell-free fetal DNA testing in maternal blood, and comprehensive molecular testing of the fetus, have greatly improved prenatal diagnostic capabilities in the context of fetal growth restriction (FGR) as shown in Chapter 24. Increased understanding and use of these resources means the likelihood of recognizing a fetal basis for FGR before birth, and managing it accordingly, will increase. The presumption of a placental basis for FGR dominates everyday clinical practice, yet paradoxically at present the application of current knowledge of what constitutes true ‘placental insufficiency’ has not translated into improved maternal care and perinatal outcomes. As an example, 33% of 650 women recruited to the landmark DIGITAT (Disproportionate Intrauterine Growth Intervention Trial at Term) trial had no postnatal evidence of FGR (defined as birth weight <10th percentile) [1]. Since obstetricians manage suspected FGR prior to delivery, they fear a risk of antepartum stillbirth and deploy frequent short-term tests of fetal well-being (biophysical profile, Doppler ultrasound, and non-stress tests), even via hospital admission, in the absence of any objective placental diagnosis. Fortunately, recent advances in the understanding of the placental basis of FGR have led to much-improved precision in both screening for the disease [2, 3] and in the prenatal diagnosis of the placental basis of FGR [4]. This chapter is designed to equip obstetricians, midwives and maternal–fetal medicine sub-specialists with key concepts in placental development and pathology that directly contribute to the care of women with suspected FGR pregnancies.