Open AccessThe capacity of mid‐pregnancy cervical length to predict preterm birth in low‐risk women: a national cohort study
Author(s) -
Ven Jeanine,
Os Melanie A.,
Kazemier Brenda M.,
Kleinrouweler Emily,
Verhoeven Corine J.,
Miranda Esteriek,
WassenaerLeemhuis Aleid G.,
Kuiper Petra N.,
Porath Martina,
Willekes Christine,
Woiski Mallory D.,
Sikkema Marko J.,
Roumen Frans J.M.E.,
Bossuyt Patrick M.,
Haak Monique C.,
Groot Christianne J.M.,
Mol Ben W.J.,
Pajkrt Eva
Publication year - 2015
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/aogs.12721
Subject(s) - medicine , obstetrics , gestation , pregnancy , prospective cohort study , cohort study , premature birth , gynecology , cohort , surgery , genetics , biology
We investigated the predictive capacity of mid‐trimester cervical length ( CL ) measurement for spontaneous and iatrogenic preterm birth. Material and methods We performed a prospective observational cohort study in nulliparous women and low‐risk multiparous women with a singleton pregnancy between 16 +0 and 21 +6 weeks of gestation. We assessed the prognostic capacity of transvaginally measured mid‐trimester CL for spontaneous and iatrogenic preterm birth (<37 weeks) using likelihood ratios ( LR ) and receiver‐operating‐characteristic analysis. We calculated numbers needed to screen to prevent one preterm birth assuming different treatment effects. Main outcome measures were preterm birth <32, <34 and <37 weeks. Results We studied 11 943 women, of whom 666 (5.6%) delivered preterm: 464 (3.9%) spontaneous and 202 (1.7%) iatrogenic. Mean CL was 44.1 mm (SD 7.8 mm). In nulliparous women, the LR s for spontaneous preterm birth varied between 27 (95% CI 7.7–95) for a CL ≤ 20 mm, and 2.0 (95% CI 1.6–2.5) for a CL between 30 and 35 mm. For low‐risk multiparous women, these LR s were 37 (95% CI 7.5–182) and 1.5 (95% CI 0.97–2.2), respectively. Using a cut‐off for CL ≤ 30 mm, 28 (6.0%) of 464 women with spontaneous preterm birth were identified. The number needed to screen to prevent one case of preterm birth was 618 in nulliparous women and 1417 for low‐risk multiparous women (40% treatment effect, cut‐off 30 mm). Conclusion In women at low risk of preterm birth, CL predicts spontaneous preterm birth. However, its isolated use as a screening tool has limited value due to low sensitivity.