Objective: The aim of this article is to assess the use of the anterior cervical angle (ACA) as a predictor of spontaneous preterm delivery (sPTD) at 20+0-24+6 weeks of gestation in an unselected population. Methods: We conducted a nested case-control study that included 93 women who later delivered spontaneously <34 weeks of gestation and 225 controls. The ACA was assessed retrospectively on all selected images using ImageJ® software. The concordance correlation coefficient was determined for the assessment of interobserver variability. Continuous variables were adjusted by maternal characteristics and expressed as the z-score or multiples of the expected normal median (MoM) of the unaffected group. Logistic regression analysis was used to evaluate whether any maternal characteristics and ultrasound variables were significantly associated with sPTD <34 weeks. Results: ACA z-score values were significantly greater in women who later delivered <34 weeks compared to controls (ACA z-score = 1.32 ± 0.57 vs. -0.09 ± 0.35; p = 0.035). The best prediction of sPTD <34 weeks was provided by a model that combined cervical length (CL) MoM, ACA z-score and maternal characteristics. For a fixed false-positive rate of 10%, the detection rate for this model was 37.6%. Conclusion: A model combining maternal history, CL and ACA at 20+0-24+6 weeks of gestation can predict approximately 40% of the severe preterm births.

Keywords:
Screening, Cervical length, Second trimester, Cervical angle, Preterm delivery
1.
Goldenberg R, Culhane J, Iams J, Romero R: Epidemiology and causes of preterm birth. Lancet 2008;371:75-84.
2.
Simcox R, Seed PT, Bennett P, Teoh T, Poston L, Shennan A: A randomized controlled trial of cervical scanning vs history to determine cerclage in women at high risk of preterm birth (CIRCLE trial). Am J Obstet Gynecol 2009;200:623.e1-623.e6
3.
Iams J, Romero R, Culhane J, Goldenberg R: Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth. Lancet 2008;371:164-175.
4.
Celik E, To M, Gajewska K, Smith G, Nicolaides KH: Cervical length and obstetric history predict spontaneous preterm birth: development and validation of a model to provide individualized risk assessment. Ultrasound Obstet Gynecol 2008;31:549-554.
5.
Hassan S, Romero R, Berry S, Dang K, Blackwell S, Treadwell M, Wolfe H: Patients with an ultrasonographic cervical length ≤15 mm have nearly a 50% risk of early spontaneous preterm delivery. Am J Obstet Gynecol 2000;182:1458-1467.
6.
Rozenberg P, Gillet A, Ville Y: Transvaginal sonographic examination of the cervix in asymptomatic pregnant women: review of the literature. Ultrasound Obstet Gynecol 2002;19:302-311.
7.
Berghella V, Roman A, Daskalakis C, Ness A, Baxter J: Gestational age at cervical length measurement and incidence of preterm birth. Obstet Gynecol 2007;110:311-317.
8.
Crane J, Hutchens D: Use of transvaginal ultrasonography to predict preterm birth in women with a history of preterm birth. Ultrasound Obstet Gynecol 2008;32:640-645.
9.
Mella M, Berghella V: Prediction of Preterm Birth: Cervical sonography. Semin Perinatol 2009;33:317-324.
10.
da Fonseca E, Bittar R, Carvalho M, Zugaib M: Prophylactic administration of progesterone by vaginal suppository to reduce the incidence of spontaneous preterm birth in women at increased risk: a randomized placebo-controlled double-blind study. Am J Obstet Gynecol 2003;188:419-424.
11.
Meis P, Klebanoff M, Thom E, Dombrowski M, Sibai B, Moawad A, Spong C, Hauth J, Miodovnik M, Varner M, Leveno K, Caritis S, Iams J, Wapner R, Conway D, O'Sullivan M, Carpenter M, Mercer B, Ramin S, Thorp J, Peaceman A: Prevention of recurrent preterm delivery by 17 alpha-hydroxyprogesterone caproate. N Engl J Med 2003;348:2379-2385.
12.
Fonseca E, Celik E, Parra M, Singh M, Nicolaides KH: Progesterone and the risk of preterm birth among women with a short cervix. N Engl J Med 2007;357:462-469.
13.
Romero R, Nicolaides K, Conde-Agudelo A, Tabor A, O'Brien JM, Cetingoz E, Da Fonseca E, Creasy GW, Klein K, Rode L, Soma-Pillay P, Fusey S, Cam C, Alfirevic Z, Hassan SS: Vaginal progesterone in women with an asymptomatic sonographic short cervix in the midtrimester decreases preterm delivery and neonatal morbidity: a systematic review and metaanalysis of individual patient data. Am J Obstet Gynecol 2012;206:124.e1-124.e19.
14.
Dharan V, Ludmir J: Alternative treatment for a short cervix: the cervical pessary. Semin Perinatol 2009;33:338-342.
15.
Goya M, Pratcorona L, Merced C, Rodó C, Valle L, Romero A, Juan M, Rodríguez A, Muñoz B, Santacruz B, Bello-Muñoz JC, Llurba E, Higueras T, Cabero L, Carreras E: Cervical pessary in pregnant women with a short cérvix (PECEP): an open-label randomised controlled trial. Lancet 2012;379:1800-1806.
16.
To MS, Palaniappan V, Skentou C, Gibb D, Nicolaides KH: Elective cerclage vs. ultrasound-indicated cerclage in high-risk pregnancies. Ultrasound Obstet Gynecol 2002;19:475-477.
17.
Berghella V, Odibo AO, To MS, Rust OA, Althuisius SM: Cerclage for short cervix on ultrasonography: meta-analysis of trials using individual patient-level data. Obstet Gynecol 2005;106:181-189.
18.
Berghella V, Seibel-Seamon J: Contemporary use of cervical cerclage. Clin Obstet Gynecol 2007;50:468-477.
19.
Mancuso M, Owen J: Prevention of preterm birth based on a short cervix: cerclage. Semin Perinatol 2009;33:325-333.
20.
Greco E, Gupta R, Syngelaki A, Poon L, Nicolaides KH: First-trimester screening for spontaneous preterm delivery with maternal characteristics and cervical length. Fetal Diagn Ther 2012;31:154-161.
21.
Son M, Grobman WA, Ayala NK, Miller ES: A universal mid-trimester transvaginal cervical length screening program and its associated reduced preterm birth rate. Am J Obstet Gynecol 2016;214:365.e1-365.e5
22.
Temming LA, Durst JK, Tuuli MG, Stout MJ, Dicke JM, Macones GA, Cahill AG: Universal cervical length screening: implementation and outcomes. Am J Obstet Gynecol 2016;214:523.e1-523.e8.
23.
Miller ES, Tita AT, Grobman WA: Second-trimester cervical length screening among asymptomatic women: an evaluation of risk-based strategies. Obstet Gynecol 2015;126:61-66.
24.
Werner EF, Hamel MS, Orzechowski K, Berghella V, Thung SF: Cost-effectiveness of transvaginal ultrasound cervical length screening in singletons without a prior preterm birth: an update. Am J Obstet Gynecol 2015;213:554.e1-554.e6.
25.
Kuusela P, Jacobsson B, Söderlund M, Bejlum C, Almström E, Ladfors L, Hagberg H, Wennerholm UB: Transvaginal sonographic evaluation of cervical length in the second trimester of asymptomatic singleton pregnancies, and the risk of preterm delivery. Acta Obstet Gynecol Scand 2015;94:598-607.
26.
Orzechowski KM, Boelig R, Nicholas SS, Baxter J, Berghella V: Is universal cervical length screening indicated in women with prior term birth? Am J Obstet Gynecol 2015;212:234.e1-234.e5.
27.
Orzechowski KM, Boelig RC, Baxter JK, Berghella V: A universal transvaginal cervical length screening program for preterm birth prevention. Obstet Gynecol 2014;124:520-525.
28.
Rane S, Guirgis R, Higgins B, Nicolaides KH: The value of ultrasound in the prediction of successful induction of labor. Ultrasound Obstet Gynecol 2004;24:538-549.
29.
Sochacki-Wójcicka N, Wojcicki J, Bomba-Opon D, Wielgos M: The anterior cervical angle as a new biophysical ultrasound marker for the prediction of spontaneous preterm birth- a proof of principle study. Ultrasound Obstet Gynecol 2015;46:377-378.
30.
Dziadosz M, Bennett TA, Dolin C, West Honart A, Pham A, Lee SS, Pivo S, Roman AS: Uterocervical angle: a novel ultrasound screening tool to predict spontaneous preterm birth. Am J Obstet Gynecol 2016, Epub ahead of print.
31.
To MS, Skentou C, Chan C, Zagaliki A, Nicolaides KH: Cervical assessment at the routine 23-week scan: standardizing techniques. Ultrasound Obstet Gynecol 2001;17:217-219.
32.
Poon LC, Kametas NA, Maiz N, Akolekar R, Nicolaides KH: First-trimester prediction of hypertensive disorders in pregnancy. Hypertension 2009;53:812-818.
33.
Lin L: A concordance correlation coefficient to evaluate reproducibility. Biometrics 1989;45:255-268.
34.
Cannie MM, Dobrescu O, Gucciardo L, Strizek B, Ziane S, Sakkas E, et al: Arabin cervical pessary in women at high risk of preterm birth: a magnetic resonance imaging observational follow-up study. Ultrasound Obstet Gynecol 2013;42:426-433.
35.
Parra-Cordero M, Sepúlveda-Martínez A, Rencoret G, Valdés E, Pedraza D, Muñoz H: Is there a role for cervical assessment and uterine artery Doppler in the first trimester of pregnancy as a screening test for spontaneous preterm delivery? Ultrasound Obstet Gynecol 2014;43:291-296.
36.
Sananes N, Meyer N, Gaudineau A, Aissi G, Boudier E, Fritz G, et al: Prediction of spontaneous preterm delivery in the first trimester of pregnancy. Eur J Obstet Gynecol Reprod Biol 2013;171:18-22.
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2016
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