The role of noninvasive diagnostic imaging in monitoring pregnancy and detecting patients at risk for preterm birth: a review of quantitative approaches

References

• Timmons B, Akins M, Mahendroo M. Cervical remodeling during pregnancy and parturition. Trends Endocrinol Metab. 2010;21(6):353–361.
   PubMed Web of Science ®Google Scholar
• Word RA, Li X-H, Hnat M, et al. Dynamics of cervical remodeling during pregnancy and parturition: mechanisms and current concepts. Seminars in reproductive medicine. New York, USA: Thieme Publishers, Inc.; 2007.
   Google Scholar
• Ananth CV, Ananth CV, Vintzileos AM. Epidemiology of preterm birth and its clinical subtypes. J Matern Fetal Neonatal Med. 2006;19(12):773–782.
   PubMed Web of Science ®Google Scholar
• Akins ML, Luby-Phelps K, Bank RA, et al. Cervical softening during pregnancy: regulated changes in collagen cross-linking and composition of matricellular proteins in the mouse. Biol Reprod. 2011;84(5):1053–1062.
   PubMed Web of Science ®Google Scholar
• Frey HA, Klebanoff MA. The epidemiology, etiology, and costs of preterm birth. Semin Fetal Neonat Med. 2016;21(2):68–73.
   Google Scholar
• James E, Wood CL, Nair H, et al. Preterm birth and the timing of puberty: a systematic review. BMC Pediatr. 2018;18(1):3.
   PubMedGoogle Scholar
• Martin JA, Osterman MJ, Centers for Disease Control and Prevention. Preterm births—United States, 2006 and 2010. MMWR Surveill Summ. 2013;62(suppl 3):136–138.
   Google Scholar
• Muglia LJ, Katz M. The enigma of spontaneous preterm birth. N Engl J Med. 2010;362(6):529–535.
   PubMed Web of Science ®Google Scholar
• Martin JA, Hamilton BE, Osterman MJ. Births in the United States, 2014. NCHS Data Brief. 2015;216:1–8.
   Google Scholar
• Greenough A. Long-term respiratory consequences of premature birth at less than 32 weeks of gestation. Early Hum Dev. 2013;89:S25–S27.
   PubMed Web of Science ®Google Scholar
• Jensen EA, Schmidt B. Epidemiology of bronchopulmonary dysplasia. Birth Defects Res A Clin Mol Teratol. 2014;100(3):145–157.
   PubMed Web of Science ®Google Scholar
• Mwaniki MK, Atieno M, Lawn JE, et al. Long-term neurodevelopmental outcomes after intrauterine and neonatal insults: a systematic review. Lancet. 2012;379(9814):445–452.
   PubMed Web of Science ®Google Scholar
• Hutchinson EA, De Luca CR, Doyle LW, et al. School-age outcomes of extremely preterm or extremely low birth weight children. Pediatrics. 2013;131(4):e1053–e1061.
   PubMed Web of Science ®Google Scholar
• Vohr B. Long-term outcomes of moderately preterm, late preterm, and early term infants. Clin Perinatol. 2013;40(4):739–751.
   PubMed Web of Science ®Google Scholar
• Butler AS, Behrman RE. Preterm birth: causes, consequences, and prevention. National Academies Press; 2007;398–401.
   Google Scholar
• Iams JD, Goldenberg RL, Meis PJ, et al. The length of the cervix and the risk of spontaneous premature delivery. N Engl J Med. 1996;334(9):567–573.
   PubMed Web of Science ®Google Scholar
• Berghella V, Tolosa JE, Kuhlman K, et al. Cervical ultrasonography compared with manual examination as a predictor of preterm delivery. Am J Obstet Gynecol. 1997;177(4):723–730.
   PubMed Web of Science ®Google Scholar
• Heath V, Southall TR, Souka AP, et al. Cervical length at 23 weeks of gestation: prediction of spontaneous preterm delivery. Ultrasound Obstet Gynecol. 1998;12(5):312–317.
   PubMed Web of Science ®Google Scholar
• Hassan SS, Romero R, Berry SM, et al. Patients with an ultrasonographic cervical length ≤15 mm have nearly a 50% risk of early spontaneous preterm delivery. Am J Obstet Gynecol. 2000;182(6):1458–1467.
   PubMed Web of Science ®Google Scholar
• Romero R, Yeo L, Miranda J, et al. A blueprint for the prevention of preterm birth: vaginal progesterone in women with a short cervix. J Perinat Med. 2013;41(1):27–44.
   PubMed Web of Science ®Google Scholar
• Lim K, Butt K, Crane JM, et al. Ultrasonographic cervical length assessment in predicting preterm birth in singleton pregnancies. J Obstet Gynaecol Canada. 2011;33(5):486–499.
   PubMedGoogle Scholar
• Yost NP, Bloom SL, Twickler DM, et al. Pitfalls in ultrasonic cervical length measurement for predicting preterm birth. Obstet Gynecol. 1999;93(4):510–516.
   PubMed Web of Science ®Google Scholar
• To M, Skentou CA, Royston P, et al. Prediction of patient‐specific risk of early preterm delivery using maternal history and sonographic measurement of cervical length: a population‐based prospective study. Ultrasound Obstet Gynecol. 2006;27(4):362–367.
   PubMed Web of Science ®Google Scholar
• Rozenberg P, Goffinet F, Malagrida L, et al. Evaluating the risk of preterm delivery: a comparison of fetal fibronectin and transvaginal ultrasonographic measurement of cervical length. Am J Obstet Gynecol. 1997;176(1):196–199.
   PubMed Web of Science ®Google Scholar
• Crane J, Hutchens D. Transvaginal sonographic measurement of cervical length to predict preterm birth in asymptomatic women at increased risk: a systematic review. Ultrasound Obstet Gynecol. 2008;31(5):579–587.
   PubMed Web of Science ®Google Scholar
• Crane J, Van den Hof M, Armson BA, et al. Transvaginal ultrasound in the prediction of preterm delivery: singleton and twin gestations. Obstet Gynecol. 1997;90(3):357–363.
   PubMed Web of Science ®Google Scholar
• Chan YL, Lam WW, Lau TK, et al. Cervical assessment by magnetic resonance imaging–its relationship to gestational age and interval to delivery. BJR. 1998;71(842):155–159.
   Google Scholar
• Pates JA, Zaretsky MV, Alexander JM, et al. Determining cervical ripeness and labor outcome: the efficacy of magnetic resonance T2 relaxation times. Obstet Gynecol. 2007;109(2):326–330.
   PubMed Web of Science ®Google Scholar
• Oláh KS. The use of magnetic resonance imaging in the assessment of the cervical hydration state. BJOG. 1994;101(3):255–257.
   Google Scholar
• House M, O'Callaghan M, Bahrami S, et al. Magnetic resonance imaging of the cervix during pregnancy: effect of gestational age and prior vaginal birth. Am J Obstet Gynecol. 2005;193(4):1554–1560.
   PubMed Web of Science ®Google Scholar
• de Tejada BM, Faltin DL, Kinkel K, et al. Magnetic resonance imaging of the cervix in women at high risk for preterm delivery. J Matern Fetal Neonatal Med. 2011;24(11):1392–1397.
   PubMed Web of Science ®Google Scholar
• Avila C, Santorelli J, Mathai J, et al. Anatomy of the fetal membranes using optical coherence tomography: part 1. Placenta. 2014;35(12):1065–1069.
   PubMed Web of Science ®Google Scholar
• Maul H, Olson G, Fittkow CT, et al. Cervical light-induced fluorescence in humans decreases throughout gestation and before delivery: preliminary observations. Am J Obstet Gynecol. 2003;188(2):537–541.
   PubMed Web of Science ®Google Scholar
• Glassman WS, Liao Q-P, Goodrum L, et al. Fluorescence probe for cervical examination during various reproductive states. Proceedings of SPIE 2980 in San Jose, CA—Advanced Fluorescence Sensing Technology III; 1997.
   Google Scholar
• Maul H, Saade G, Garfield RE. Prediction of term and preterm parturition and treatment monitoring by measurement of cervical cross-linked collagen using light-induced fluorescence. Acta Obstet Gynecol Scand. 2005;84(6):534–536.
   PubMed Web of Science ®Google Scholar
• Zhang Y, Akins ML, Murari K, et al. A compact fiber-optic SHG scanning endomicroscope and its application to visualize cervical remodeling during pregnancy. Proc Natl Acad Sci. 2012;109(32):12878–12883.
   PubMed Web of Science ®Google Scholar
• Kleissl HP, Van der Rest M, Naftolin F, et al. Collagen changes in the human uterine cervix at parturition. Am J Obstet Gynecol. 1978;130(7):748–753.
   PubMed Web of Science ®Google Scholar
• Oxlund BS, Ørtoft G, Brüel A, et al. Collagen concentration and biomechanical properties of samples from the lower uterine cervix in relation to age and parity in non-pregnant women. Reprod Biol Endocrinol. 2010;8(1):82.
   PubMedGoogle Scholar
• Yao W, Gan Y, Myers KM, et al. Collagen fiber orientation and dispersion in the upper cervix of non-pregnant and pregnant women. PLOS One. 2016;11(11):e0166709.
   PubMed Web of Science ®Google Scholar
• Muñoz-de-Toro M, Varayoud J, Ramos J, et al. Collagen remodeling during cervical ripening is a key event for successful vaginal delivery. Braz J Morphol Sci. 2003;20:75–84.
   Google Scholar
• Nott JP, Bonney EA, Pickering JD, et al. The structure and function of the cervix during pregnancy. Transl Res Anat. 2016;2:1–7.
   Google Scholar
• Myers KM, Feltovich H, Mazza E, et al. The mechanical role of the cervix in pregnancy. J Biomech. 2015;48(9):1511–1523.
   PubMed Web of Science ®Google Scholar
• Hassan SS, Romero R, Tarca AL, et al. Signature pathways identified from gene expression profiles in the human uterine cervix before and after spontaneous term parturition. Am J Obstet Gynecol. 2007;197(3):250 e1–250 e7.
   Web of Science ®Google Scholar
• Hassan SS, Romero R, Tarca AL, et al. The transcriptome of cervical ripening in human pregnancy before the onset of labor at term: identification of novel molecular functions involved in this process. J Matern Fetal Neonatal Med. 2009;22(12):1183–1193.
   PubMed Web of Science ®Google Scholar
• Hassan SS, Romero R, Haddad R, et al. The transcriptome of the uterine cervix before and after spontaneous term parturition. Am J Obstet Gynecol. 2006;195(3):778–786.
   PubMed Web of Science ®Google Scholar
• Hassan SS, Romero R, Pineles B, et al. MicroRNA expression profiling of the human uterine cervix after term labor and delivery. Am J Obstet Gynecol. 2010;202(1):80 e1–80 e8.
   Web of Science ®Google Scholar
• Hassan SS, Romero R, Tarca AL, et al. The molecular basis for sonographic cervical shortening at term: identification of differentially expressed genes and the epithelial-mesenchymal transition as a function of cervical length. Am J Obstet Gynecol. 2010;203(5):472 e1–472 e14.
   Web of Science ®Google Scholar
• Becher N, Hein M, Danielsen CC, et al. Matrix metalloproteinases and their inhibitors in the cervical mucus plug at term of pregnancy. Am J Obstet Gynecol. 2004;191(4):1232–1239.
   PubMed Web of Science ®Google Scholar
• Leppert PC. Anatomy and physiology of cervical ripening. Clinic Obstet Gynecol. 1995;38(2):267–279.
   PubMed Web of Science ®Google Scholar
• Straach KJ. Regulation of hyaluronan expression during cervical ripening. Glycobiology. 2004;15(1):55–65.
   PubMed Web of Science ®Google Scholar
• Uchiyama T, Matsumoto T, Suzuki Y, et al. Endogenous hyaluronan: a cytokine-like factor present in rabbit uterine cervix during pregnancy. Biol Pharm Bull. 2004;27(12):1907–1912.
   PubMed Web of Science ®Google Scholar
• Mahendroo M. Cervical remodeling in term and preterm birth: insights from an animal model. Reproduction. 2012;143(4):429–438.
   PubMed Web of Science ®Google Scholar
• Guerrero QW, Drehfal LC, Rosado-Mendez IM, et al. Monitoring collagen remodeling in the cervix with quantitative ultrasound. In Reproductive sciences. Thousand Oaks, CA USA: Sage Publications Inc; 2007.
   Google Scholar
• Hernandez-Andrade E, Hassan SS, Ahn H, et al. Evaluation of cervical stiffness during pregnancy using semiquantitative ultrasound elastography. Ultrasound Obstet Gynecol. 2013;41(2):152–161.
   PubMed Web of Science ®Google Scholar
• Burdet J, Rubio A, Salazar A, et al. Inflammation, infection and preterm birth. CPD. 2014;20(29):4741–4748.
   Google Scholar
• Agrawal V, Hirsch E. Intrauterine infection and preterm labor. Semin Fetal Neonat Med. Elsevier; 2012;17(1):12–19.
   Google Scholar
• Romero R, Chaiworapongsa T, Espinoza J. Micronutrients and intrauterine infection, preterm birth and the fetal inflammatory response syndrome. J Nutr. 2003;133(5):1668S–1673S.
   PubMed Web of Science ®Google Scholar
• House M, Socrate S. The cervix as a biomechanical structure. Ultrasound Obstet Gynecol. 2006;28(6):745–749.
   PubMed Web of Science ®Google Scholar
• Barnett SB, Ter Haar GR, Ziskin MC, et al. International recommendations and guidelines for the safe use of diagnostic ultrasound in medicine. Ultrasound Med Biol. 2000;26(3):355–366.
   PubMed Web of Science ®Google Scholar
• Hershkovitz R, Sheiner E, Mazor M. Ultrasound in obstetrics: a review of safety. Eur J Obstet Gynecol Reprod Biol. 2002;101(1):15–18.
   PubMed Web of Science ®Google Scholar
• Honest H, Bachmann LM, Coomarasamy A, et al. Accuracy of cervical transvaginal sonography in predicting preterm birth: a systematic review. Ultrasound Obstet Gynecol. 2003;22(3):305–322.
   PubMed Web of Science ®Google Scholar
• Mella MT, Berghella V. Prediction of preterm birth: cervical sonography. Semin Perinatol. 2009;33(5):317–324.
   Google Scholar
• Burger M, Weber‐Rössler T, Willmann M. Measurement of the pregnant cervix by transvaginal sonography: an interobserver study and new standards to improve the interobserver variability. Ultrasound Obstet Gynecol. 1997;9(3):188–193.
   PubMed Web of Science ®Google Scholar
• Westerway SC, Pedersen LH, Hyett J. Cervical length measurement: comparison of transabdominal and transvaginal approach. Australas J Ultrasound Med. 2015;18(1):19–26.
   PubMedGoogle Scholar
• Hassan SS, Romero R, Vidyadhari D, for the PREGNANT Trial, et al. Vaginal progesterone reduces the rate of preterm birth in women with a sonographic short cervix: a multicenter, randomized, double-blind, placebo-controlled trial. Ultrasound Obstet Gynecol. 2011;38(1):18–31
   PubMed Web of Science ®Google Scholar
• Berghella V, Odibo AO, Tolosa JE. Cerclage for prevention of preterm birth in women with a short cervix found on transvaginal ultrasound examination: a randomized trial. Am J Obstet Gynecol. 2004;191(4):1311–1317.
   PubMed Web of Science ®Google Scholar
• To MS, Alfirevic Z, Heath VC, et al. Cervical cerclage for prevention of preterm delivery in woman with short cervix: randomised controlled trial. The Lancet. 2004;363(9424):1849–1853.
   PubMed Web of Science ®Google Scholar
• Parra-Saavedra M, Gómez L, Barrero A, et al. Prediction of preterm birth using the cervical consistency index. Ultrasound Obstet Gynecol. 2011;38(1):44–51.
   PubMed Web of Science ®Google Scholar
• Banos N, Murillo-Bravo C, Julià C, et al. Mid-trimester sonographic cervical consistency index to predict spontaneous preterm birth in a low-risk population. Ultrasound Obstet Gynecol. 2018;51(5):629–636.
   PubMed Web of Science ®Google Scholar
• Kongwattanakul K, Saksiriwuttho P, Komwilaisak R, et al. Short cervix detection in pregnant women by transabdominal sonography with post-void technique. J Med Ultrasonics. 2016;43(4):519–522.
   PubMed Web of Science ®Google Scholar
• Jackson GM, Ludmir J, Bader TJ. The accuracy of digital examination and ultrasound in the evaluation of cervical length. Obstet Gynecol. 1992;79(2):214–218.
   PubMed Web of Science ®Google Scholar
• Roh H-J, Ji YI, Jung CH, et al. Comparison of cervical lengths using transabdominal and transvaginal sonography in midpregnancy. J Ultrasound Med. 2013;32(10):1721–1728.
   PubMed Web of Science ®Google Scholar
• Rust OA, Atlas RO, Reed J et al. Revisiting the short cervix detected by transvaginal ultrasound in the second trimester: why cerclage therapy may not help. Am J Obstetrics Gynecol. 2001;185(5):1098–1105.
   PubMed Web of Science ®Google Scholar
• Severi FM, Bocchi C, Florio P, et al. Comparison of two-dimensional and three-dimensional ultrasound in the assessment of the cervix to predict preterm delivery. Ultrasound Med Biol. 2003;29(9):1261–1265.
   PubMed Web of Science ®Google Scholar
• House M, Feltovich H, Hall TJ, et al. Three-dimensional, extended field-of-view ultrasound method for estimating large strain mechanical properties of the cervix during pregnancy. Ultrason Imaging. 2012;34(1):1–14.
   PubMed Web of Science ®Google Scholar
• Park IY, Kwon, JY, Kwon, JY, et al. Usefulness of cervical volume by three-dimensional ultrasound in identifying the risk for preterm birth. Ultrasound Med Biol. 2011;37(7):1039–1045.
   PubMed Web of Science ®Google Scholar
• Berghella V, Daly SF, Tolosa JE, et al. Prediction of preterm delivery with transvaginal ultrasonography of the cervix in patients with high-risk pregnancies: does cerclage prevent prematurity? Am J Obstet Gynecol. 1999;181(4):809–815.
   PubMed Web of Science ®Google Scholar
• Rust OA, Atlas RO, Kimmel S, et al. Does the presence of a funnel increase the risk of adverse perinatal outcome in a patient with a short cervix? Am J Obstet Gynecol. 2005;192(4):1060–1066.
   PubMed Web of Science ®Google Scholar
• Albayrak E, Dogru HY, Ozmen Z, et al. Is evaluation of placenta with real-time sonoelastography during the second trimester of pregnancy an effective method for the assessment of spontaneous preterm birth risk? Clin Imaging. 2016;40(5):926–930.
   PubMed Web of Science ®Google Scholar
• Berghella V, Bega G, Tolosa JE, et al. Ultrasound assessment of the cervix. Clin Obstet Gynecol. 2003;46(4):947–962.
   PubMed Web of Science ®Google Scholar
• Dziadosz M, Bennett T-A, Dolin C, et al. Uterocervical angle: a novel ultrasound screening tool to predict spontaneous preterm birth. Am J Obstet Gynecol. 2016;215(3):376.e1–376.e7.
   Web of Science ®Google Scholar
• Sochacki-Wojcicka N, Wojcicki J, Bomba-Opon D, et al. Anterior cervical angle as a new biophysical ultrasound marker for prediction of spontaneous preterm birth. Ultrasound Obstet Gynecol. 2015;46(3):377–378.
   PubMed Web of Science ®Google Scholar
• Yost NP, Owen J, Berghella V, et al. Second-trimester cervical sonography: features other than cervical length to predict spontaneous preterm birth. Obstet Gynecol. 2004;103(3):457–462.
   PubMed Web of Science ®Google Scholar
• Turan OM, Turan S, Funai EF, et al. Fetal adrenal gland volume: a novel method to identify women at risk for impending preterm birth. Obstet Gynecol. 2007;109(4):855–862.
   PubMed Web of Science ®Google Scholar
• Turan OM, Turan S, Funai EF, et al. Ultrasound measurement of fetal adrenal gland enlargement: an accurate predictor of preterm birth. Am J Obstet Gynecol. 2011;204(4):311.e1–311.e10.
   PubMed Web of Science ®Google Scholar
• Romero R, Kusanovic JP, Espinoza J, et al. What is amniotic fluid ‘sludge’? Ultrasound Obstet Gynecol. 2007;30(5):793–798.
   PubMed Web of Science ®Google Scholar
• Espinoza J, Gonçalves LF, Romero R, et al. The prevalence and clinical significance of amniotic fluid ‘sludge’ in patients with preterm labor and intact membranes. Ultrasound Obstet Gynecol. 2005;25(4):346–352.
   PubMed Web of Science ®Google Scholar
• Ventura W, Nazario C, Ingar J, et al. Risk of impending preterm delivery associated with the presence of amniotic fluid sludge in women in preterm labor with intact membranes. Fetal Diagn Ther. 2011;30(2):116–121.
   PubMed Web of Science ®Google Scholar
• Hall TJ, Feltovich H, Rosado-Mendez IM, et al. Quantitative ultrasound of the uterine cervix. J Acoust Soc Am. 2016;140(4):3137–3137.
   Google Scholar
• Baños N, Perez-Moreno A, Migliorelli F, et al. Quantitative analysis of the cervical texture by ultrasound and correlation with gestational age. Fetal Diagn Ther. 2017;41(4):265–272.
   PubMed Web of Science ®Google Scholar
• Baños N, Perez-Moreno A, Julià C, et al. Quantitative analysis of cervical texture by ultrasound in mid-pregnancy and association with spontaneous preterm birth. Ultrasound Obstet Gynecol. 2018;51(5):637–643.
   PubMed Web of Science ®Google Scholar
• Feltovich H, Nam K, Hall TJ. Quantitative ultrasound assessment of cervical microstructure. Ultrason Imaging. 2010;32(3):131–142.
   PubMed Web of Science ®Google Scholar
• Feltovich H, Hall TJ, Berghella V. Beyond cervical length: emerging technologies for assessing the pregnant cervix. Am J Obstet Gynecol. 2012;207(5):345–354.
   PubMed Web of Science ®Google Scholar
• Feltovich H, Hall T. Quantitative imaging of the cervix: setting the bar. Ultrasound Obstet Gynecol. 2013;41(2):121–128.
   PubMed Web of Science ®Google Scholar
• Clark K, Ji H, Feltovich H, et al. Mifepristone-induced cervical ripening: structural, biomechanical, and molecular events. Am J Obstet Gynecol. 2006;194(5):1391–1398.
   PubMed Web of Science ®Google Scholar
• Guerrero QW, Carlson LC, Feltovich H, et al. Quantitative ultrasound backscatter parameters in the human cervix. IEEE International Ultrasonics Symposium (IUS); Chicago, IL; 2014. p. 224–227.
   Google Scholar
• McFarlin BL, O'Brien WD, Oelze ML, et al. Quantitative ultrasound assessment of the rat cervix. J Ultrasound Med. 2006;25(8):1031–1040.
   PubMed Web of Science ®Google Scholar
• Bigelow TA, McFarlin BL, O’Brien WD, et al. In vivo ultrasonic attenuation slope estimates for detecting cervical ripening in rats: preliminary results. J Acoust Soc Am. 2008;123(3):1794–1800.
   PubMed Web of Science ®Google Scholar
• McFarlin BL, Bigelow TA, Laybed Y, et al. Ultrasonic attenuation estimation of the pregnant cervix: a preliminary report. Ultrasound Obstet Gynecol. 2010;36(2):218–225.
   PubMed Web of Science ®Google Scholar
• Tekesin I, Hellmeyer L, Heller G, et al. Evaluation of quantitative ultrasound tissue characterization of the cervix and cervical length in the prediction of premature delivery for patients with spontaneous preterm labor. Am J Obstet Gynecol. 2003;189(2):532–539.
   PubMed Web of Science ®Google Scholar
• Swiatkowska-Freund M, Preis K. Cervical elastography during pregnancy: clinical perspectives. Int J Women Health. 2017;9:245.
   PubMed Web of Science ®Google Scholar
• Dietrich CF, Barr RG, Farrokh A, et al. Strain elastography-how to do it? Ultrasound Int Open. 2017;3(4):E137.
   PubMed Web of Science ®Google Scholar
• Carlson LC, Feltovich H, Palmeri ML, et al. Estimation of shear wave speed in the human uterine cervix. Ultrasound Obstet Gynecol. 2014;43(4):452–458.
   PubMed Web of Science ®Google Scholar
• Zhi H, Xiao X-Y, Yang H-Y, et al. Ultrasonic elastography in breast cancer diagnosis: strain ratio vs 5-point scale. Acad Radiol. 2010;17(10):1227–1233.
   PubMed Web of Science ®Google Scholar
• Hernandez-Andrade E, Garcia M, Ahn H, et al. Strain at the internal cervical os assessed with quasi-static elastography is associated with the risk of spontaneous preterm delivery at ≤34 weeks of gestation. J Perinat Med. 2015;43(6):657–666.
   PubMed Web of Science ®Google Scholar
• Hernandez-Andrade E, Romero R, Korzeniewski SJ, et al. Cervical strain determined by ultrasound elastography and its association with spontaneous preterm delivery. J Perinat Med. 2014;42(2):159–169.
   PubMed Web of Science ®Google Scholar
• Köbbing K, Fruscalzo A, Hammer K, et al. Quantitative elastography of the uterine cervix as a predictor of preterm delivery. J Perinatol. 2014;34(10):774–780.
   PubMed Web of Science ®Google Scholar
• Oturina V, Hammer K, Möllers M, et al. Assessment of cervical elastography strain pattern and its association with preterm birth. J Perinat Med. 2017;45(8).
   PubMed Web of Science ®Google Scholar
• von Schöning D, Fischer T, von Tucher E, et al. Cervical sonoelastography for improving prediction of preterm birth compared with cervical length measurement and fetal fibronectin test. J Perinat Med. 2015;43(5):531–536.
   PubMed Web of Science ®Google Scholar
• Wozniak S, Czuczwar P, Szkodziak P, et al. Elastography in predicting preterm delivery in asymptomatic, low-risk women: a prospective observational study. BMC Pregnancy Childbirth. 2014;14(1):238.
   PubMedGoogle Scholar
• Woźniak S, Czuczwar P, Szkodziak P, et al. Elastography for predicting preterm delivery in patients with short cervical length at 18–22 weeks of gestation: a prospective observational study. Ginekologia Polska. 2015;86(6):442–447.
   PubMed Web of Science ®Google Scholar
• Hernandez‐Andrade E, Hassan SS, Ahn H, et al. Evaluation of cervical stiffness during pregnancy using semiquantitative ultrasound elastography. Ultrasound Obstet Gynecol. 2013;41(2):152–161.
   PubMed Web of Science ®Google Scholar
• Thomas A. Imaging of the cervix using sonoelastography. Ultrasound Obstet Gynecol. 2006;28(3):356–357.
   PubMed Web of Science ®Google Scholar
• Khalil MR, Thorsen P, Uldbjerg N. Cervical ultrasound elastography may hold potential to predict risk of preterm birth. Dan Med J. 2013;60(1):A4570.
   PubMed Web of Science ®Google Scholar
• Gennisson J-L, Muller M, Gabor P, et al. Quantification of elasticity changes in the myometrium during labor using supersonic shear imaging: a feasibility study. Ultrasonics. 2015;56:183–188.
   PubMed Web of Science ®Google Scholar
• Hernandez-Andrade E, Aurioles-Garibay A, Garcia M, et al. Effect of depth on shear-wave elastography estimated in the internal and external cervical os during pregnancy. J Perinat Med. 2014;42(5):549–557.
   PubMed Web of Science ®Google Scholar
• Li WJ, Wei ZT, Yan RL, et al. Detection of placenta elasticity modulus by quantitative real-time shear wave imaging. Clin Exp Obstet Gynecol. 2012;39(4):470–473.
   PubMed Web of Science ®Google Scholar
• Peralta L, Molina FS, Melchor J, et al. Transient elastography to assess the cervical ripening during pregnancy: a preliminary study. Ultraschall Med. 2017;38(4):395–402.
   PubMed Web of Science ®Google Scholar
• Muller M, Aït-Belkacem D, Hessabi M, et al. Assessment of the cervix in pregnant women using shear wave elastography: a feasibility study. Ultrasound Med Biol. 2015;41(11):2789–2797.
   PubMed Web of Science ®Google Scholar
• Woodward LJ, Anderson PJ, Austin NC, et al. Neonatal MRI to predict neurodevelopmental outcomes in preterm infants. N Engl J Med. 2006;355(7):685–694.
   PubMed Web of Science ®Google Scholar
• Plaisier A, Raets MMA, van der Starre C, et al. Safety of routine early MRI in preterm infants. Pediatr Radiol. 2012;42(10):1205–1211.
   PubMed Web of Science ®Google Scholar
• Groves AM, Chiesa G, Durighel G, et al. Functional cardiac MRI in preterm and term newborns. Arch Dis Child Fetal Neonatal Ed. 2010;96(2):F86–F91.
   PubMed Web of Science ®Google Scholar
• Habib VVF, Araujo Júnior E, Sun SY, et al. Early indicators of cervical insufficiency assessed using magnetic resonance imaging of the cervix during pregnancy. J Matern Fetal Neonatal Med. 2015;28(6):626–631.
   PubMed Web of Science ®Google Scholar
• Masselli G, Perrone G, Kinkel K, et al. Are second trimester apparent diffusion coefficient values of the short uterine cervix associated with impending preterm delivery? Radiology. 2016;280(3):897–904.
   PubMed Web of Science ®Google Scholar
• House M, Kaplan DL, Socrate S. Relationships between mechanical properties and extracellular matrix constituents of the cervical stroma during pregnancy. Semin Perinatol. 2009;33(5):300–307.
   Google Scholar
• Pates JA, Yost NP, Oliver Q, et al. Magnetic resonance signal characteristics of the cervix as pregnancy advances. Reprod Sci. 2007;14(5):440–444.
   PubMed Web of Science ®Google Scholar
• Nunes V, Cross J, Speich JE, et al. Fetal membrane imaging and the prediction of preterm birth: a systematic review, current issues, and future directions. BMC Pregnancy Childbirth. 2016;16(1):387.
   PubMedGoogle Scholar
• Moutquin JM. Classification and heterogeneity of preterm birth. BJOG. 2003;110(s20):30–33.
   PubMedGoogle Scholar
• Mueller-Heubach E, Rubinstein DN, Schwarz SS. Histologic chorioamnionitis and preterm delivery in different patient populations. Obstet Gynecol. 1990;75(4):622–626.
   PubMed Web of Science ®Google Scholar
• Low G, Kruse SA, Lomas DJ. General review of magnetic resonance elastography. WJR. 2016;8(1):59.
   Web of Science ®Google Scholar
• Jiang X, Asbach P, Streitberger K-J, et al. In vivo high-resolution magnetic resonance elastography of the uterine corpus and cervix. Eur Radiol. 2014;24(12):3025–3033.
   PubMed Web of Science ®Google Scholar
• Chen J, Kugel J, Yin M, et al. Magnetic resonance elastrography of other organs. In Magnetic resonance elastography; Venkatesh S, Ehman R (eds). Springer; 2014: p. 119–133.
   Google Scholar
• Olson G, et al. Noninvasive measurement of cervical collagen content in women approaching delivery. Am J Obstet Gynecol. 1998;178(1S):91S.
   PubMedGoogle Scholar
• Vargis E, Brown N, Williams K, et al. Detecting biochemical changes in the rodent cervix during pregnancy using Raman spectroscopy. Ann Biomed Eng. 2012;40(8):1814–1824.
   PubMed Web of Science ®Google Scholar
• Vargis E, Webb CN, Paria BC, et al. Detecting changes during pregnancy with Raman spectroscopy. IEEE Biomedical Sciences and Engineering Conference (BSEC); Knoxville, TN; 2011.
   Google Scholar
• O’brien CM, Vargis E, Rudin A, et al. In vivo Raman spectroscopy for biochemical monitoring of the human cervix throughout pregnancy. Am J Obstet Gynecol. 2018;218(5):528.e1–528.e18.
   Web of Science ®Google Scholar
• O’brien CM, Vargis E, Paria BC, et al. Raman spectroscopy provides a noninvasive approach for determining biochemical composition of the pregnant cervix in vivo. Acta Paediatr. 2014;103(7):715–721.
   PubMed Web of Science ®Google Scholar
• Chen MM, Coakley FV, Kaimal A, et al. Guidelines for computed tomography and magnetic resonance imaging use during pregnancy and lactation. Obstet Gynecol. 2008;112(2, Part 1):333–340.
   PubMed Web of Science ®Google Scholar
• Kopelman TR, Bogert JN, Walters JW, et al. Computed tomographic imaging interpretation improves fetal outcomes after maternal trauma. J Trauma Acute Care Surg. 2016;81(6):1131–1135.
   PubMed Web of Science ®Google Scholar
• Sotiriadis A, Papatheodorou S, Kavvadias A, et al. Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta‐analysis. Ultrasound Obstet Gynecol. 2010;35(1):54–64.
   PubMed Web of Science ®Google Scholar
• Vayssière C, Favre R, Audibert F, et al. Cervical length and funneling at 22 and 27 weeks to predict spontaneous birth before 32 weeks in twin pregnancies: a French prospective multicenter study. Am J Obstet Gynecol. 2002;187(6):1596–1604.
   PubMed Web of Science ®Google Scholar
• Sochacki‐Wójcicka N, Wojcicki J, Bomba-Opon D, et al. Anterior cervical angle as a new biophysical ultrasound marker for prediction of spontaneous preterm birth. Ultrasound Obstet Gynecol. 2015;46(3):377–378.
   PubMed Web of Science ®Google Scholar
• Carlson LC, Romero ST, Palmeri ML, et al. Changes in shear wave speed pre‐and post‐induction of labor: a feasibility study. Ultrasound Obstet Gynecol. 2015;46(1):93–98.
   PubMed Web of Science ®Google Scholar
• Carlson LC, Feltovich H, Palmeri ML, et al. Statistical analysis of shear wave speed in the uterine cervix. IEEE Trans Ultrason Ferroelect Freq Contr. 2014;61(10):1651–1660.
   PubMed Web of Science ®Google Scholar
• Peralta L, Mourier E, Richard C, et al. In vivo evaluation of cervical stiffness evolution during induced ripening using shear wave elastography, histology and 2 photon excitation microscopy: insight from an animal model. PLOS One. 2015;10(8):e0133377.
   PubMed Web of Science ®Google Scholar
• Butler HJ, Ashton L, Bird B, et al. Using Raman spectroscopy to characterize biological materials. Nat Protoc. 2016;11(4):664–687.
   PubMed Web of Science ®Google Scholar
• Başaran D, Özyüncü Ö, Kara Ö, et al. Ultrasonographic measurement of amniochorionic membrane in asymptomatic pregnant women is not a useful tool for preterm birth prediction. J Obstet Gynaecol Res. 2014;40(1):62–66.
   PubMed Web of Science ®Google Scholar
• O’Brien CM, Herington JL, Brown N, et al. In vivo Raman spectral analysis of impaired cervical remodeling in a mouse model of delayed parturition. Sci Rep. 2017;7(1):6835.
   PubMedGoogle Scholar
• Alshahrani S, Yan Y, Avrutsky I, et al. An advanced photoacoustic tomography system based on a ring geometry design. Proceedings, SPIE 10580 Medical Imaging 2018: Ultrasonic Imaging and Tomography, International Society for Optics and Photonics, Houston, Texas, United States, 2018.
   Google Scholar
• Qu M, Mehrmohammadi M, Emelianov S. Detection of nanoparticle endocytosis using magneto‐photoacoustic imaging. Small. 2011;7(20):2858–2862.
   PubMed Web of Science ®Google Scholar
• Yan Y, Basij M, Hemandez-Andrade E, et al. Endocavity ultrasound and photoacoustic imaging system to evaluate fetal brain perfusion and oxygenation: preliminary ex vivo studies. In IEEE International Ultrasonics Symposium (IUS); Washington, D.C.; 2017.
   Google Scholar
• Mozaffarzadeh M, Yan Y, Mehrmohammadi M, et al. Enhanced linear-array photoacoustic beamforming using modified coherence factor. J Biomed Opt. 2018;23(2):1.
   Web of Science ®Google Scholar
• Qu M, Mallidi S, Mehrmohammadi M, et al. Magneto-photo-acoustic imaging. Biomed Opt Express. 2011;2(2):385–396.
   PubMed Web of Science ®Google Scholar
• Mehrmohammadi M, Joon Yoon S, Yeager D, et al. Photoacoustic imaging for cancer detection and staging. CMI. 2013;2(1):89–105.
   Google Scholar
• Bouchard R, Sahin O, Emelianov S. Ultrasound-guided photoacoustic imaging: current state and future development. IEEE Trans Ultrason Ferroelect Freq Contr. 2014;61(3):450–466.
   PubMed Web of Science ®Google Scholar
• Xu M, Wang LV. Photoacoustic imaging in biomedicine. Rev Sci Instrum. 2006;77(4):041101.
   Web of Science ®Google Scholar
• Park S, Shah J, Aglyamov SR, et al. Integrated system for ultrasonic, photoacoustic and elasticity imaging. Proceedings of the 2006 SPIE Medical Imaging Symposium: Ultrasonic Imaging and Signal Processing; San Diego, CA; 2006.
   Google Scholar
• Zhang HF, Maslov K, Stoica G, et al. Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging. Nat Biotechnol. 2006;24(7):848–851.
   PubMed Web of Science ®Google Scholar
• Esenaliev RO, Larina IV, Larin KV, et al. Optoacoustic technique for noninvasive monitoring of blood oxygenation: a feasibility study. Appl Opt. 2002;41(22):4722–4731.
   PubMed Web of Science ®Google Scholar
• Hysi E, Saha RK, Kolios MC. Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation. J Biomed Opt. 2012;17(12):125006–125006.
   PubMed Web of Science ®Google Scholar
• Laufer J, Elwell C, Delpy D, et al. In vitro measurements of absolute blood oxygen saturation using pulsed near-infrared photoacoustic spectroscopy: accuracy and resolution. Phys Med Biol. 2005;50(18):4409–4428.
   PubMed Web of Science ®Google Scholar
• Li M-L, Oh J-T, Xie X, et al. Simultaneous molecular and hypoxia imaging of brain tumors in vivo using spectroscopic photoacoustic tomography. Proc IEEE. 2008;96(3):481–489.
   Web of Science ®Google Scholar
• Yan Y, Dong J, Siddiqu AA, et al. Ultrasound, elasticity, and photoacoustic imaging of cervix: towards a more accurate prediction of preterm delivery. Conference presentation at Medical Imaging 2018: Ultrasonic Imaging and Tomography. Houston, TX: International Society for Optics and Photonics; 2018.
   Google Scholar
• Basij M, Yan Y, Alshahrani SS, et al. Combined phased-array ultrasound and photoacoustic endoscope for gynecologic cancer imaging applications. Conference presentation at Medical Imaging 2018: Ultrasonic Imaging and Tomography. Houston, TX: International Society for Optics and Photonics; 2018
   Google Scholar
• Yan Y, Gomez-Lopez N, Basij M, et al. Photoacoustic imaging of the uterine cervix to assess collagen and water content changes in murine pregnancy. Biomed Opt Express. 2019;10(9):4643.
   PubMed Web of Science ®Google Scholar
• Hernádi L, Töröcsik M. Screening for fetal anomalies in the 12th week of pregnancy by transvaginal sonography in an unselected population. Prenat Diagn. 1997;17(8):753–759.
   PubMed Web of Science ®Google Scholar
• Paladini D, Volpe P. Ultrasound of congenital fetal anomalies: differential diagnosis and prognostic indicators. 2014. Boca Raton, FL; CRC Press.
   Google Scholar
• Dyson RL, Pretorius DH, Budorick NE, et al. Three‐dimensional ultrasound in the evaluation of fetal anomalies. Ultrasound Obstet Gynecol. 2000;16(4):321–328.
   PubMed Web of Science ®Google Scholar
• Jauniaux E, Campbell S. Ultrasonographic assessment of placental abnormalities. Am J Obstet Gynecol. 1990;163(5):1650–1658.
   PubMed Web of Science ®Google Scholar
• Eydoux P, Choiset A, Le Porrier N, et al. Chromosomal prenatal diagnosis: study of 936 cases of intrauterine abnormalities after ultrasound assessment. Prenat Diagn. 1989;9(4):255–269.
   PubMed Web of Science ®Google Scholar
• Rizzo G, Capponi A, Cavicchioni O, et al. First trimester uterine Doppler and three-dimensional ultrasound placental volume calculation in predicting pre-eclampsia. Eur J Obstet Gynecol Reprod Biol. 2008;138(2):147–151.
   PubMed Web of Science ®Google Scholar
• Berghella V, Rafael TJ, Szychowski JM, et al. Cerclage for short cervix on ultrasonography in women with singleton gestations and previous preterm birth: a meta-analysis. Obstet Gynecol. 2011;117(3):663–671.
   PubMed Web of Science ®Google Scholar
• Kurjak A, Miskovic B, Andonotopo W, et al. How useful is 3D and 4D ultrasound in perinatal medicine? J Perinat Med. 2007;35(1):10–27.
   PubMed Web of Science ®Google Scholar
• Bega G, Lev-Toaff A, Kuhlman K, et al. Three‐dimensional multiplanar transvaginal ultrasound of the cervix in pregnancy. Ultrasound Obstet Gynecol. 2000;16(4):351–358.
   PubMed Web of Science ®Google Scholar
• Aglyamov SR, Karpiouk AB, Mehrmohammadi M, et al. Elasticity imaging and sensing using targeted motion: from macro to nano. Curr Med Imag. 2012;8(1):3–15.
   Web of Science ®Google Scholar
• Sarvazyan A, Hall JT, Urban WM, et al. An overview of elastography-an emerging branch of medical imaging. CMIR. 2011;7(4):255–282.
   Google Scholar
• Zhu Y-Z, Peng G-Q, Tian G-X, et al. New model for predicting preterm delivery during the second trimester of pregnancy. Sci Rep. 2017;7(1):11294.
   PubMedGoogle Scholar
• Palmeri M, Feltovich H, Homyk A, et al. Evaluating the feasibility of acoustic radiation force impulse shear wave elasticity imaging of the uterine cervix with an intracavity array: a simulation study. IEEE Trans Ultrason, Ferroelect Freq Contr. 2013;60(10):2053–2064.
   PubMed Web of Science ®Google Scholar
• Carlson LC, Hall TJ, Rosado-Mendez IM, et al. Detection of changes in cervical softness using shear wave speed in early versus late pregnancy: an in vivo cross-sectional study. Ultrasound Med Biol. 2017;44(3):515–521.
   PubMed Web of Science ®Google Scholar
• Swiatkowska‐Freund M, Preis K. Elastography of the uterine cervix: implications for success of induction of labor. Ultrasound Obstet Gynecol. 2011;38(1):52–56.
   PubMed Web of Science ®Google Scholar
• Wang LV, Hu S. Photoacoustic tomography: in vivo imaging from organelles to organs. Science. 2012;335(6075):1458–1462.
   PubMed Web of Science ®Google Scholar
• Wang X, Pang Y, Ku G, et al. Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain. Nat Biotechnol. 2003;21(7):803–806.
   PubMed Web of Science ®Google Scholar
• Beard P. Biomedical photoacoustic imaging. Interface Focus. 2011;1(4):602–631.
   PubMed Web of Science ®Google Scholar
• Wang X, Xie X, Ku G, et al. Noninvasive imaging of hemoglobin concentration and oxygenation in the rat brain using high-resolution photoacoustic tomography. J Biomed Opt. 2006;11(2):024015.
   PubMed Web of Science ®Google Scholar
• Yan Y, Basij M, Wang Z, et al. Multi-parametric acoustic imaging of cervix for more accurate detection of patients at risk of preterm birth. IEEE International Ultrasonics Symposium (IUS); Kobe, Japan; 2018.
   Google Scholar
• Varrey A, Mehrmohammadi M, Garg A, et al. 17: Photoacoustic imaging of the uterine cervix: a novel method to characterize tissue composition. Am J Obstet Gynecol. 2019;220(1):S14–S15.
   Web of Science ®Google Scholar
• Basij M, Yan Y, Alshahrani SS, et al. Miniaturized phased-array ultrasound and photoacoustic endoscopic imaging system. Photoacoustics. 2019;15:100139.
   PubMed Web of Science ®Google Scholar
• Alshahrani SS, Yan Y, Alijabbari N, et al. All-reflective ring illumination system for photoacoustic tomography. J Biomed Opt. 2019;24(4):046004.
   Web of Science ®Google Scholar
• Alijabbari N, Alshahrani SS, Pattyn A, et al. Photoacoustic tomography with a ring ultrasound transducer: a comparison of different illumination strategies. Appl Sci. 2019;9(15):3094.
   Google Scholar
• Alshahrani S, Pattyn A, Alijabbari N, et al. The Effectiveness of the omnidirectional illumination in full-ring photoacoustic tomography. IEEE International Ultrasonics Symposium (IUS); Kobe, Japan; 2018.
   Google Scholar
• Qu Y, Hu P, Shi J, et al. In vivo characterization of connective tissue remodeling using infrared photoacoustic spectra. J Biomed Opt. 2018;23(12):121621.
   Web of Science ®Google Scholar
• Mallidi S, Luke GP, Emelianov S. Photoacoustic imaging in cancer detection, diagnosis, and treatment guidance. Trends Biotechnol. 2011;29(5):213–221.
   PubMed Web of Science ®Google Scholar
• Rosado-Mendez IM, Palmeri ML, Drehfal LC, et al. Assessment of structural heterogeneity and viscosity in the cervix using shear wave elasticity imaging: initial results from a Rhesus Macaque Model. Ultrasound Med Biol. 2017;43(4):790–803.
   PubMed Web of Science ®Google Scholar
• Reusch LM, Anderson J, Carlson LC, et al. Detecting cervical microstructure via ultrasound and optical microscopy. IEEE International Ultrasonics Symposium (IUS); San Diego, CA; 2010.
   Google Scholar
• Liang W, Sakulsaengprapha V, Luby-Phelps K, et al. Quantitative analyses of SHG endomicroscopy images of cervical collagen network for detecting preterm birth in mouse models. Conference presented at Clinical and Translational Biophotonics. Hollywood, FL: Optical Society of America; 2018.
   Google Scholar
• Mottley JG, Miller J. Anisotropy of the ultrasonic backscatter of myocardial tissue: I. Theory and measurements in vitro. J Acoust Soc Am. 1988;83(2):755–761.
   PubMed Web of Science ®Google Scholar
• Madaras EI, Perez J, Sobel BE, et al. Anisotropy of the ultrasonic backscatter of myocardial tissue: II. Measurements in vivo. J Acoust Soc Am. 1988;83(2):762–769.
   PubMed Web of Science ®Google Scholar
• Mottley JG, Miller JG. Anisotropy of the ultrasonic attenuation in soft tissues: Measurements in vitro. J Acoust Soc Am. 1990;88(3):1203–1210.
   PubMed Web of Science ®Google Scholar
• Turquin E, Varray F, Petrusca L, et al. 3D ultrasound imaging of tissue anisotropy using spatial coherence: comparison between plane and diverging waves. IEEE International Ultrasonics Symposium (IUS); Washington, D.C.; 2017.
   Google Scholar
• Guerrero QW, Feltovich H, Rosado-Mendez IM et al. Anisotropy and spatial heterogeneity in quantitative ultrasound parameters: relevance to the study of the human cervix. Ultrasound Med Biol. 2018;44(7):1493–1503.
   PubMed Web of Science ®Google Scholar
• Buhimschi IA, Dussably L, Buhimschi CS, et al. Physical and biomechanical characteristics of rat cervical ripening are not consistent with increased collagenase activity. Am J Obstet Gynecol. 2004;191(5):1695–1704.
   PubMed Web of Science ®Google Scholar
• Uldbjerg N, Ekman G, Malmström A, et al. Ripening of the human uterine cervix related to changes in collagen, glycosaminoglycans, and collagenolytic activity. Am J Obstet Gynecol. 1983;147(6):662–666.
   PubMed Web of Science ®Google Scholar
• Nallasamy S, Akins M, Tetreault B, et al. Distinct reorganization of collagen architecture in lipopolysaccharide-mediated premature cervical remodeling. Biol Reprod. 2017;98(1):63–74.
   Web of Science ®Google Scholar
• Kuon RJ, Shi SQ, Maul H, et al. A novel optical method to assess cervical changes during pregnancy and use to evaluate the effects of progestins on term and preterm labor. Am J Obstet Gynecol. 2011;205(1):82.e15–82.e20.
   Web of Science ®Google Scholar
• Mowa C, Jesmin S, Sakuma I, et al. Characterization of vascular endothelial growth factor (VEGF) in the uterine cervix over pregnancy: effects of denervation and implications for cervical ripening. J Histochem Cytochem. 2004;52(12):1665–1674.
   PubMed Web of Science ®Google Scholar
• Spector W, Willoughby D. The inflammatory response. Bacteriol Rev. 1963;27(2):117–154.
   PubMedGoogle Scholar
• Pober JS, Sessa WC. Inflammation and the blood microvascular system. Cold Spring Harb Perspect Biol. 2015;7(1):a016345.
   Web of Science ®Google Scholar
• Hari Kishore A, Li X-H, Word RA. Hypoxia and PGE2 regulate MiTF-CX during cervical ripening. Mol Endocrinol. 2012;26(12):2031–2045.
   PubMedGoogle Scholar
• Yellon SM. Contributions to the dynamics of cervix remodeling prior to term and preterm birth. Biol Reprod. 2017;96(1):13–23.
   PubMed Web of Science ®Google Scholar
• Strehl C, Fangradt M, Fearon U, et al. Hypoxia: how does the monocyte‐macrophage system respond to changes in oxygen availability? J Leukocyte Biol. 2014;95(2):233–241.
   PubMed Web of Science ®Google Scholar
• Barnum CE, Fey JL, Weiss SN, et al. Tensile mechanical properties and dynamic collagen fiber re-alignment of the murine cervix are dramatically altered throughout pregnancy. J Biomech Eng. 2017;139(6):061008.
   Web of Science ®Google Scholar