A baby born before 37 weeks of pregnancy is considered premature. Slightly fewer than 12 percent of all babies are premature. Overall, the rate of premature births is rising, mainly due to the large numbers of multiple births in recent years. Twins and other multiples are about six times more likely to be premature than single birth babies. The rate of premature single births is slightly increasing each year. Other terms often used for prematurity are preterm and "preemie." Preterm generally refers to the pregnancy (as in preterm labor), while premature is more often used to describe your baby. Many premature babies also weigh less than 2,500 grams (5 .5 pounds) and may be referred to as low birthweight (LBW).

How Boston Children's approaches prematurity

Boston Children's is at the forefront of major research conducted on premature newborns. Boston Children's was one of the first hospitals to use gene-chip analyses to study diseases in premature newborns. Additionally, our specialized Growth and Nutrition Program at Boston Children's Hospital is specifically designed to help children with poor growth and feeding difficulties. And our NICU is routinely ranked as one of the best in the country.