A second birth only compounds these concerns. A decline in the share of births to mothers with less than 12 years of education, from 24 percent in 1990 to 22 percent in 1998. Research has consistently shown that a mother's educational level is associated with several child outcomes, including infant mortality and a child's educational attainment. Low-birthweight babies are at higher risk of death, disability, and other illness than are babies born at normal weight. The percentage of babies that were born preterm, or before the 37th week of pregnancy, increased from 11 percent in 1990 to 12 percent in 1998.
Many preterm babies are also low-birthweight and face the same health risks.
An increase in the percentage of total births to unmarried women, from 28 percent in 1990 to 33 percent in 1998. Most of this increase occurred in the 1990-1994 period, and this figure has been relatively constant the past few years. Children born to unmarried mothers face a greater risk of poor birth outcomes and of poverty than do children born to married mothers. The Right Start City Trends , the companion to this volume, paints a bleaker picture for babies born in the nation's largest cities. On every measure presented here, except smoking during pregnancy, babies born in urban America fare much worse than those born in the rest of the nation.