Low Birth Weight and Prematurity: Effects on Child Development Outcomes

Low birth weight (LBW) and preterm birth are related phenomena about which more has been written with regard to child outcomes than any other set of variables in the pre- and perinatal literature. With a literature of thousands of articles related to the etiology and associated economic, sociological, psychological and medical correlates, this literature is difficult to summarize. This chapter is specifically devoted to outcomes for children and will not directly address the etiology of low birth weight or prematurity. Etiology is in large part what the remainder of this book is about since each of the conditions described under the heading of maternal medical complications, maternal substance abuse and maternal exposure to pollutants during pregnancy results in low birth weight and preterm delivery. But even limiting this chapter to outcome studies associated with children’s learning and behavior problems, the available literature is far too large to be summarized here. Thus, the chapter will review only the most important trends in this literature. Further, primary consideration will be given to LBW. This is done for two reasons. First, LBW is easier to measure than premature birth; thus it is the subject of far more important studies than prematurity. Second, the correlation between premature birth and LBW is very high (greater than.80), so much of this review applies to premature birth.

The purpose of this chapter is to present an overview of the LBW outcomes in relation to intelligence, specific cognitive abilities, behavior and academic performance. In addition, this chapter will discuss the pathophysiological mechanisms by which LBW relates to such outcomes. Prior to embarking on such review, it is important to define LBW and distinguish it from preterm birth and intrauterine growth restriction (IUGR).