Preterm birth prevention: an evaluation of programs in the United States.

During the last decade several programs were established to prevent the onset of preterm labor and facilitate its early identification and treatment. Although these prevention programs shared a similar goal, they varied in their primary outcome focus, target populations, study designs, and specific intervention components. Their initial reports were promising; however, subsequent evaluations of efforts in the United States produced mixed results. The current literature is suggestive of the benefits of programs to prevent preterm labor and delivery, but methodologic differences among them and deficiencies in the reported evaluations have rendered a final verdict equivocal. Many studies using historical or geographic controls found positive results, whereas randomized, controlled trials did not find a significant impact. Positive results were found in studies using low-risk populations, but investigations of high-risk patients noted little effect. Together with continued research on the factors that underlie the onset of labor, additional assessment of these programs and their individual intervention components appears to be necessary.