ABSTRACT
The dramatic increases in twin births in recent years in the United States and other countries, have been accompanied by dramatic reductions in twin neona-tal and infant mortality over the past two decades1-3. For example, the number of twin births in the United States increased by 52% between 1980 (n=68 339) and 1997 (n=104 137), whereas the corresponding rate of twinning increased by 42% from 18.9 to 26.8 per 1000 births in the same period1. At the same time, the rate of infant mortality among twins in the United States declined by 42% between 1980 and 1997 from 50.0 per 1000 twin live births in 1983-84 to 29.2 per 1000 twin live births in 1995-964. In spite of the impressive declines in twin infant mortality rates, most reductions in infant deaths are attributed to declining rates of death from birth asphyxia, neonatal sepsis and respiratory dis-tress syndrome5,6. Surprisingly, infant mortality rates from congenital anomalies have increased, and con-sequently, congenital anomalies have emerged as the leading cause of infant deaths7-9.
