This book is based on the 20th Study Group of the Royal College of Obstetricians and Gynaecologists, which concerned the important topic of fetal growth. Basic scientific and both obstetric and paediatric aspects of the subject were addressed in contributions from many different disciplines. The deliberations covered the broad topics of normal fetal growth, fetal overgrowth and fetal undergrowth. Clinical implications of these entities, especially fetal undergrowth, played a large part in the proceedings as dictated by clinical concerns. Definitions, epidemiology, aetiology and screening were covered, as were technological developments, with special reference to blood flow and volume flow measurements, both fetal and placental. Other aspects of clinical fetal monitoring, including fetal activity measurements, and biophysical evaluation were rationalised and placed in context, and the important newly emerging areas of cordocentesis and therapy in IUGR addressed. Finally, neonatal management of the SGA baby, mortality and long-term morbidity were discussed.The formal papers presented by the members of the Study Group are given together with edited versions of the ensuing discussions and the Group's conclusions.