From 1950 to 1977, infant mortality dropped from 30 to 14 deaths per 1,000 live births. The annual decline in infant mortality between 1965 and 1973 was 3.5 percent. The proportion of women receiving prenatal care during the first 3 months of pregnancy also increased-from 68 to 74 percent during the years 1969 to 1977. The factors underlying improvements in infant mortality are complex, but include increased access to prenatal services, increased availability of regionalized intensive care units, and improvements in maternal nutritional status. The principal threats to infant health are birth defects that can lead to lifelong handicapping conditions, and problems associated with low birth weight. Today, approximately seven percent of all babies are of low birth weight (2,500 grams or less). Unfortunately, many children are born to women with an increased risk of having a low birth weight infant, i.e., women making no prenatal visit during the first trimester, and teenagers. Further, in 1978 1 in 4 women giving birth made no prenatal visit during the first trimester and 1 in 20 made no prenatal visit during the first two trimesters.