title: Targeted therapy for threatened preterm labor based on sonographic measurement of the cervical length: a randomized controlled trial.
abstract: OBJECTIVE
  False positive diagnosis of preterm labor is common. As a consequence, medications including corticosteroids to promote fetal lung maturity and tocolysis are prescribed unnecessarily. We tested the hypothesis that management of threatened preterm labor based on measurement of cervical length by ultrasonography can reduce the number of women who receive inappropriate treatment.
  
  
  METHODS
  Forty-one women with threatened preterm labor for whom a clinical decision was made to prescribe antenatal corticosteroids and tocolysis were randomized to have their cervical length measured by transvaginal ultrasound (n=21) or to receive therapy as planned (n=20). Fourteen women in the ultrasound group had a cervix longer than 15 mm and the therapy was withheld, while the other seven with a short cervix were managed in the same way as the control group.
  
  
  RESULTS
  Three women (14%) in the ultrasound group were treated inappropriately with antenatal corticosteroids because they remained undelivered for more than a week. This compared favorably with the control group where 18 out of 20 (90%) received corticosteroids unnecessarily (relative risk (RR) 0.16; 95% confidence interval (CI), 0.05-0.39). Tocolysis was given to only seven women (33.3%) in the ultrasound group compared with 20 (100%) in the control group (RR 0.3; 95% CI, 0.15-0.54). There were no babies in either group who were born prematurely without being given a full course of antenatal corticosteroid therapy.
  
  
  CONCLUSIONS
  Women with threatened preterm labor and cervical length more than 15 mm should not receive tocolysis. The issue of the safety of withholding corticosteroid therapy in this clinical scenario warrants further study.
authors.affiliation: University Division of Reproductive and Perinatal Medicine, Liverpool Women's Hospital, UK.
authors.forename: Z
authors.initials: Z
authors.lastname: Alfirevic
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Allen-Coward
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: F
authors.initials: F
authors.lastname: Molina
authors.affiliation: 'Hospital clinico San Cecilio', Granada, Spain.
authors.forename: C P
authors.initials: CP
authors.lastname: Vinuesa
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
authors.forename: K
authors.initials: K
authors.lastname: Nicolaides
mesh_terms: D000305:Adrenal Cortex Hormones / Q000009:adverse effects*; D002584:Cervix Uteri / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D015145:Tocolysis; D016216:Ultrasonography, Prenatal / Q000379:methods*
chemical_list: D000305:Adrenal Cortex Hormones