6 - Experimental restriction of fetal growth

Summary

Introduction

Restricted fetal growth is common in human pregnancy and is associated with increased perinatal morbidity and mortality and an increased risk of adverse outcomes in later life. Similarly, restricted fetal growth in domestic animals results in poor perinatal outcome and reduced productivity. The term ‘restricted fetal growth’ is used increasingly in preference to ‘intrauterine growth retardation’, since the latter has unfortunate connotations for consumers of health services. To prevent, diagnose and treat restricted fetal growth successfully, greater understanding of its origins and consequences, as well as careful evaluation of potential therapeutic strategies, is needed. The study of experimental restriction of fetal growth in animals is an essential element in obtaining this knowledge.

Experimentally, the approaches used to restrict fetal growth in animals reflect the different questions being asked. Some are devised to mimic known or suspected causes of naturally occurring fetal growth restriction, to determine if such factors are involved causatively by imposing them for varying periods at different stages of development. Some perturbations can be produced chronically, and are used to examine the consequences for the individual in the medium to long term. Yet others are designed to identify/delineate the specific physiological, cellular and molecular mechanisms by which perturbations restrict growth and alter development of key fetal organs and tissues.

This chapter will document these varied approaches and put them into the context of our current understanding of human and animal fetal growth restriction.