Since 1933, when a noteworthy increase in the Infant Mortality Rate (IMR) was observed, the historical trend of the IMR has been steady or sometimes rapidly decline. The IMR dropped by an average of 4%/year, through the 1930s and 1940s. The rate of decline slowed noticeably to 1%/ year from 1950 to 1964. Afterwards, IMR declined rapidly, by an average of almost 5%/ year until the early 1980s. Although the pace of decline has slowed somewhat since the mid-1990s, significant declines in late fetal mortality and infant mortality have been observed through 2001 despite substantial increases in preterm and LBW risk, two important predictors of perinatal health. Retinopathy of prematurity is an ocular disorder involving vascular proliferation in premature infants, which affects motor, lingual, mental, and social development of affected individuals.
