Preterm labor and birth: what have we learned in the past two decades?

Preterm births in the United States reached a 20-year high of 11.9% in 2001. Preterm and low-birth-weight births are the end result of multiple pathways. This article examines two decades of multidisciplinary research related to preterm birth from both individual and ecologic perspectives. The difficulties in identifying women who will have preterm birth, risk factors amenable to change in the preconception and prenatal periods, and strategies for intervention are described, along with maternal treatment to improve infant outcomes. Future directions for nursing practice and research are suggested.