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A correction has been published: N Engl J Med 2003;349(5):513.
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Background The measurement of the frequency of uterine contractions has not been useful for reducing the rate of preterm delivery in randomized trials. Nonetheless, ambulatory monitoring of contractions continues to be used in clinical practice.
Methods We assessed the frequency of uterine contractions as a predictor of the risk of spontaneous preterm delivery before 35 weeks of gestation. We enrolled women with singleton pregnancies between 22 and 24 weeks of gestation. The women used a contraction monitor at home to record contraction frequency twice daily on 2 or more days per week from enrollment to delivery or 37 weeks of gestation.
Results We obtained 34,908 hours of successful monitoring recordings from 306 women. Although more contractions were recorded from women who delivered before 35 weeks than from women who delivered at 35 weeks or later, we could identify no threshold frequency that effectively identified women who delivered preterm infants. The sensitivity and positive predictive value of a maximal hourly frequency of contractions of four or more between 4 p.m. and 3:59 a.m. were 9 percent and 25 percent, respectively, at 22 to 24 weeks and 28 percent and 23 percent at 27 to 28 weeks. Other proposed screening tests, such as digital and ultrasound evaluations of the cervix and assays for fetal fibronectin in cervicovaginal secretions, also had low sensitivity and positive predictive value for preterm labor.
Source Information
From the departments of obstetrics and gynecology at Ohio State University, Columbus (J.D.I.); the Medical University of South Carolina, Charleston (R.B.N.); the University of Alabama, Birmingham (R.L.G.); Wake Forest University, Winston-Salem, N.C. (E.M.-H.); the University of Chicago, Chicago (A.M.); the University of Tennessee, Memphis (B.M.S.); the University of Pittsburgh–Magee Women's Hospital, Pittsburgh (S.N.C.); the University of Cincinnati, Cincinnati (M.M.); the University of Southern California, Los Angeles (R.H.P.); Wayne State University, Detroit (M.P.D.); the Biostatistics Center at George Washington University, Washington, D.C. (E.A.T.); and the National Institute of Child Health and Human Development, Bethesda, Md. (D.M.).
Gary Thurnau, M.D., University of Oklahoma, Oklahoma City, was another author.
Address reprint requests to Dr. Iams at the Department of Obstetrics and Gynecology, Ohio State University, 1654 Upham Dr., Columbus, OH 43210-1228.
This article has been cited by other articles:
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