Introduction

There is considerable controversy in interpreting data relating intrauterine growth restriction (IUGR) both to short-term health effects occurring during infancy and childhood and to longer-term consequences throughout the lifespan. This chapter reviews areas of debate and presents current information on these effects. The discussion begins with the link between IUGR and infant mortality and morbidity. Next, the evidence of effects of IUGR on growth through infancy and childhood is discussed, followed by a review of the evidence describing the impact of IUGR on neurological development. We then turn to the controversial subject of longer-term effects of IUGR in adulthood, reviewing Barker's programming theory and the studies supporting it, as well as the critiques of this theory.

IUGR and infant mortality and morbidity

IUGR is one of the known leading causes of death in infants. As the degree of growth restriction increases, so too does the risk of death. Infants weighing 2000–2499 gm at birth are approximately four times as likely to die in the neonatal period than are infants weighing 2500–2999 gm, who in turn are twice as likely to die than are infants weighing 3000–3499 gm. This relative risk of death in each 500 gm birth weight interval has been found to hold true across different populations (Tebers et al., 1988).

The association between IUGR and increased infant mortality extends into the post-neonatal period and holds for such causes of death as sudden infant death syndrome and infection.