Delivery before the 37th week is called a premature, or preterm,
delivery. A premature delivery can cause problems for the infants if their
organs are not fully developed. Infants delivered before 32 weeks have greater
health risks than those who are delivered at 32 weeks of
gestation or later.
Multiple pregnancies seldom reach the usual 40-week due date:footnote 1
For twins, the average time to delivery is 36 to
For triplets, the average time is 33
For quadruplets, the average time is 31 weeks.
After delivery, most premature babies need care in a hospital unit
called the neonatal intensive care unit (NICU). Care in the NICU can last days
or weeks, depending on a baby's condition and the amount of specialized care
the baby needs.
Bush MC, Pernoll ML (2013). Multiple gestation. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 301-309. New York: McGraw-Hill.