In 1999, prematurity/low birthweight (lbw) accounted for 4,304 neonatal deaths (under 28 days), reflecting a rate of neonatal mortality due to prematurity/lbw of 23.0 per 100,000 live births.  Birth defects were the second leading cause of neonatal mortality (20.9 per 100,000), followed by maternal pregnancy complications (7.4), respiratory distress syndrome (RDS—5.7), and newborns affected by complications of the placenta, cord and membranes (5.4).  Together, these five causes accounted for 62.3 percent of all neonatal deaths in 1999.