HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by YOST, N. P. Articles by LEVENO, K. J. Search for Related Content PubMed PubMed Citation Articles by YOST, N. P. Articles by LEVENO, K. J.

Pitfalls in Ultrasonic Cervical Length Measurement for Predicting Preterm Birth

From the Departments of Obstetrics and Gynecology, and Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.

Address reprint requests to: Nicole P. Yost, MD, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9032, E-mail: lmcdon{at}mednet.swmed.edu

Objective: To describe the anatomic and technical difficulties encountered with transvaginal ultrasound imaging of the cervix in a consecutive series of women at risk for preterm delivery.

Methods: Three groups of women had cervical ultrasound examinations: those with histories of preterm birth, those with incompetent cervices, and those admitted for preterm labor that did not progress. Standardized ultrasound examinations of the cervix involved measuring the length of the endocervical canal, funneling length, and internal os dilation with and without fundal pressure.

Results: Sixty consecutive women had transvaginal ultrasound examinations for assessment of the cervix. Forty-six had histories of preterm birth, five had incompetent cervices, and nine had arrested preterm labor. Six types of problems arose, which can be divided into anatomic or technical considerations, with an overall frequency of 27% (95% confidence interval 16%, 40%). Anatomic pitfalls that hampered identification of the internal os included an undeveloped lower uterine segment (n = 5), a focal myometrial contraction (n = 1), rapid and spontaneous cervical change (n = 1), and an endocervical polyp (n = 1). Technical pitfalls included incorrect interpretation of internal os dilation because of vaginal probe orientation (n = 7) and artificial lengthening of the endocervical canal because of distortion of the cervix by the transducer (n = 1).

Conclusion: We caution those who perform cervical length examinations to be wary of falsely reassuring findings due to potential anatomic and technical pitfalls.

This article has been cited by other articles:

				A. M. A. Madsen Sonographic Methods of Evaluating Cervical Length: A Literature Review Journal of Diagnostic Medical Sonography, May 1, 2003; 19(3): 157 - 165. [Abstract] [PDF]

				J. D. Iams Prediction and Early Detection of Preterm Labor Obstet. Gynecol., February 1, 2003; 101(2): 402 - 412. [Abstract] [Full Text] [PDF]

				N. P. Yost, J. Owen, V. Berghella, C. MacPherson, M. Swain, G. A. Dildy III, M. Miodovnik, O. Langer, B. Sibai, and for the National Institute of Child Health and Hum Second-Trimester Cervical Sonography: Features Other Than Cervical Length to Predict Spontaneous Preterm Birth Obstet. Gynecol., January 1, 1999; 103(3): 457 - 462. [Abstract] [Full Text]