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Can transabdominal ultrasound exclude short cervix?
Author(s)
Vincenzo Berghella, MD

Preterm birth (PTB) remains a major cause of perinatal morbidity and mortality, and so its prediction and prevention are 2 of the most important issues in obstetrics. Cervical length (CL) measured by ultrasound has been shown to be the best predictor; several interventions (vaginal progesterone and cerclage) have been shown to be effective at reducing PTB if a short CL is identified. In fact, both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recommend CL being measured every 2 weeks from 16 to 23 weeks in singletons with prior spontaneous PTB (sPTB), with cerclage placed for CL less than 25 mm. Moreover, both ACOG and SMFM recommend that “universal CL screening” (CL measured in singletons without a prior sPTB) be considered as a single measurement at about 18 to 23 weeks.

Details of the study
Rhoades and colleagues present data on CL screening done by transabdominal ultrasound (TAU), as an alternative to transvaginal ultrasound (TVU). This study confirms early data:

  1. TAU cannot visualize CL in several women (20.6%).
  2. To make sure a high sensitivity (92.9% in this study) is achieved to detect a TVU CL less than 30 mm, a high cutoff (in this case 35 mm) needs to be used with TAU. Nonetheless, 7% of women with a short TVU CL would not be detected, raising clinical and legal issues.
  3. A high percentage (in this case 32.4%; 103/318) of women screened by TAU would screen positive (TAU CL less than 35 mm) and therefore need to have a TVU anyway.
  4. Overall, more than 50% (in this study 53%–20.6% because TAU could not visualize CL, and 32.4% because TAU was less than 35 mm) of women having TAU CL screening would need to have TVU anyway! In the largest study comparing TAU to TVU CL screening (TABLE1–6), 66% of women screened by TAU would have to be screened also by TVU.5

There are several other reasons why TVU is considered the gold standard for CL screening, and instead TAU CL should be avoided as possible. All randomized controlled trials that showed benefit from interventions (vaginal progesterone, cerclage, pessary) aimed at decreasing PTB in women with short CL used TVU CL screening and never TAU CL screening. In addition, TAU CL is less accurate than TVU CL screening. On TAU, fetal parts can obscure the cervix, obesity makes it hard to visualize CL, the distance between probe and cervix is longer, manual pressure can mask CL shortening, and bladder filling can elongate CL.7 Cost-effectiveness studies show that TVU CL screening is more effective, and less costly, compared with TAU CL screening, even in singletons without a prior sPTB.8

Societies such as ACOG and SMFM all have recommended TVU CL for prediction and prevention of PTB, over TAU CL.9,10 Importantly, a TVU CL should be done by sonographers educated and trained formally, through such programs as those made available by SMFM.11

What this evidence means for practice
If CL assessment is done, TVU should be preferred, as it is the gold standard, and not TAU.
>>Vincenzo Berghella, MD


Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.

References

  1. Saul LL, Kurtzman JT, Hagemann C, Ghamsary M, Wing DA. Is transabdominal sonography of the cervix after voiding a reliable method of cervical length assessment? J Ultrasound Med. 2008;27(9):1305−1311.
  2. Stone PR, Chan EH, McCowan LM, Taylor RS, Mitchell JM; SCOPE Consortium. Aust N Z J Obstet Gynaecol. 2010;50(6):523−527.
  3. To MS, Skentou C, Cicero S, Nicolaides KH. Cervical assessment at the routine 23-weeks’ scan: problems with transabdominal sonography. Ultrasound Obstet Gynecol 2000;15(4):292−296.
  4. Hernandez-Andrade E, Romero R, Ahn H, et al. Transabdominal evaluation of uterine cervical length during pregnancy fails to identify a substantial number of women with a short cervix. 2012;25(9):1682−1689.
  5. Friedman AM, Srinivas SK, Parry S, et al. Can transabdominal ultrasound be used as a screening test for short cervical length? Am J Obstet Gynecol. 2013;208(3):190.e1−e7.
  6. Rhoades JS, Park JM, Stout MJ, Macones GA, Cahill AG, Tuuli MG. Can transabdominal cervical length measurement exclude short cervix? 2015 Nov 2. [Epub ahead of print]
  7. Berghella V, Bega G, Tolosa JE, Berghella M. Ultrasound assessment of the cervix. Clin Obstet Gynecol. 2003; 46(4):947–623.
  8. Miller ES, Grobman WA. Cost-effectiveness of transabdominal ultrasound for cervical length screening for preterm birth prevention. Am J Obstet Gynecol. 2013;209(6): 546.e1–e6.
  9. American College of Obstetricians and Gynecologists. Practice bulletin No. 130: prediction and prevention of preterm birth. Obstet Gynecol. 2012;120(4):964–973.
  10. Society for Maternal-Fetal Medicine Publications Committee; Berghella V. Progesterone and preterm birth prevention: translating clinical trial data into clinical practice. Am J Obstet Gynecol. 2012;206(5):376–386.
  11. Cervical Length Education and Review (CLEAR) guidelines. https://clear.perinatalquality.org. Published 2015. Accessed December 15, 2015.
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expert commentary

Vincenzo Berghella, MD
Professor of Obstetrics and Gynecology and Director of the Division of Maternal-Fetal Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania.

The author reports no financial relationships relevant to this article.

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Legacy Keywords
Vincenzo Berghella MD, transabdominal ultrasound, TAU, short cervix, cervical length, CL, preterm birth, PTB, spontaneous preterm birth, sPTB, vaginal progesterone, cerclage, ACOG, SMFM, transvaginal ultrasound, TVU
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expert commentary

Vincenzo Berghella, MD
Professor of Obstetrics and Gynecology and Director of the Division of Maternal-Fetal Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania.

The author reports no financial relationships relevant to this article.

Author and Disclosure Information

expert commentary

Vincenzo Berghella, MD
Professor of Obstetrics and Gynecology and Director of the Division of Maternal-Fetal Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania.

The author reports no financial relationships relevant to this article.

Article PDF
OBGManagement_BerghellaV_January.PDF
Article PDF
OBGManagement_BerghellaV_January.PDF

Preterm birth (PTB) remains a major cause of perinatal morbidity and mortality, and so its prediction and prevention are 2 of the most important issues in obstetrics. Cervical length (CL) measured by ultrasound has been shown to be the best predictor; several interventions (vaginal progesterone and cerclage) have been shown to be effective at reducing PTB if a short CL is identified. In fact, both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recommend CL being measured every 2 weeks from 16 to 23 weeks in singletons with prior spontaneous PTB (sPTB), with cerclage placed for CL less than 25 mm. Moreover, both ACOG and SMFM recommend that “universal CL screening” (CL measured in singletons without a prior sPTB) be considered as a single measurement at about 18 to 23 weeks.

Details of the study
Rhoades and colleagues present data on CL screening done by transabdominal ultrasound (TAU), as an alternative to transvaginal ultrasound (TVU). This study confirms early data:

  1. TAU cannot visualize CL in several women (20.6%).
  2. To make sure a high sensitivity (92.9% in this study) is achieved to detect a TVU CL less than 30 mm, a high cutoff (in this case 35 mm) needs to be used with TAU. Nonetheless, 7% of women with a short TVU CL would not be detected, raising clinical and legal issues.
  3. A high percentage (in this case 32.4%; 103/318) of women screened by TAU would screen positive (TAU CL less than 35 mm) and therefore need to have a TVU anyway.
  4. Overall, more than 50% (in this study 53%–20.6% because TAU could not visualize CL, and 32.4% because TAU was less than 35 mm) of women having TAU CL screening would need to have TVU anyway! In the largest study comparing TAU to TVU CL screening (TABLE1–6), 66% of women screened by TAU would have to be screened also by TVU.5

There are several other reasons why TVU is considered the gold standard for CL screening, and instead TAU CL should be avoided as possible. All randomized controlled trials that showed benefit from interventions (vaginal progesterone, cerclage, pessary) aimed at decreasing PTB in women with short CL used TVU CL screening and never TAU CL screening. In addition, TAU CL is less accurate than TVU CL screening. On TAU, fetal parts can obscure the cervix, obesity makes it hard to visualize CL, the distance between probe and cervix is longer, manual pressure can mask CL shortening, and bladder filling can elongate CL.7 Cost-effectiveness studies show that TVU CL screening is more effective, and less costly, compared with TAU CL screening, even in singletons without a prior sPTB.8

Societies such as ACOG and SMFM all have recommended TVU CL for prediction and prevention of PTB, over TAU CL.9,10 Importantly, a TVU CL should be done by sonographers educated and trained formally, through such programs as those made available by SMFM.11

What this evidence means for practice
If CL assessment is done, TVU should be preferred, as it is the gold standard, and not TAU.
>>Vincenzo Berghella, MD


Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.

Preterm birth (PTB) remains a major cause of perinatal morbidity and mortality, and so its prediction and prevention are 2 of the most important issues in obstetrics. Cervical length (CL) measured by ultrasound has been shown to be the best predictor; several interventions (vaginal progesterone and cerclage) have been shown to be effective at reducing PTB if a short CL is identified. In fact, both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recommend CL being measured every 2 weeks from 16 to 23 weeks in singletons with prior spontaneous PTB (sPTB), with cerclage placed for CL less than 25 mm. Moreover, both ACOG and SMFM recommend that “universal CL screening” (CL measured in singletons without a prior sPTB) be considered as a single measurement at about 18 to 23 weeks.

Details of the study
Rhoades and colleagues present data on CL screening done by transabdominal ultrasound (TAU), as an alternative to transvaginal ultrasound (TVU). This study confirms early data:

  1. TAU cannot visualize CL in several women (20.6%).
  2. To make sure a high sensitivity (92.9% in this study) is achieved to detect a TVU CL less than 30 mm, a high cutoff (in this case 35 mm) needs to be used with TAU. Nonetheless, 7% of women with a short TVU CL would not be detected, raising clinical and legal issues.
  3. A high percentage (in this case 32.4%; 103/318) of women screened by TAU would screen positive (TAU CL less than 35 mm) and therefore need to have a TVU anyway.
  4. Overall, more than 50% (in this study 53%–20.6% because TAU could not visualize CL, and 32.4% because TAU was less than 35 mm) of women having TAU CL screening would need to have TVU anyway! In the largest study comparing TAU to TVU CL screening (TABLE1–6), 66% of women screened by TAU would have to be screened also by TVU.5

There are several other reasons why TVU is considered the gold standard for CL screening, and instead TAU CL should be avoided as possible. All randomized controlled trials that showed benefit from interventions (vaginal progesterone, cerclage, pessary) aimed at decreasing PTB in women with short CL used TVU CL screening and never TAU CL screening. In addition, TAU CL is less accurate than TVU CL screening. On TAU, fetal parts can obscure the cervix, obesity makes it hard to visualize CL, the distance between probe and cervix is longer, manual pressure can mask CL shortening, and bladder filling can elongate CL.7 Cost-effectiveness studies show that TVU CL screening is more effective, and less costly, compared with TAU CL screening, even in singletons without a prior sPTB.8

Societies such as ACOG and SMFM all have recommended TVU CL for prediction and prevention of PTB, over TAU CL.9,10 Importantly, a TVU CL should be done by sonographers educated and trained formally, through such programs as those made available by SMFM.11

What this evidence means for practice
If CL assessment is done, TVU should be preferred, as it is the gold standard, and not TAU.
>>Vincenzo Berghella, MD


Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.

References

  1. Saul LL, Kurtzman JT, Hagemann C, Ghamsary M, Wing DA. Is transabdominal sonography of the cervix after voiding a reliable method of cervical length assessment? J Ultrasound Med. 2008;27(9):1305−1311.
  2. Stone PR, Chan EH, McCowan LM, Taylor RS, Mitchell JM; SCOPE Consortium. Aust N Z J Obstet Gynaecol. 2010;50(6):523−527.
  3. To MS, Skentou C, Cicero S, Nicolaides KH. Cervical assessment at the routine 23-weeks’ scan: problems with transabdominal sonography. Ultrasound Obstet Gynecol 2000;15(4):292−296.
  4. Hernandez-Andrade E, Romero R, Ahn H, et al. Transabdominal evaluation of uterine cervical length during pregnancy fails to identify a substantial number of women with a short cervix. 2012;25(9):1682−1689.
  5. Friedman AM, Srinivas SK, Parry S, et al. Can transabdominal ultrasound be used as a screening test for short cervical length? Am J Obstet Gynecol. 2013;208(3):190.e1−e7.
  6. Rhoades JS, Park JM, Stout MJ, Macones GA, Cahill AG, Tuuli MG. Can transabdominal cervical length measurement exclude short cervix? 2015 Nov 2. [Epub ahead of print]
  7. Berghella V, Bega G, Tolosa JE, Berghella M. Ultrasound assessment of the cervix. Clin Obstet Gynecol. 2003; 46(4):947–623.
  8. Miller ES, Grobman WA. Cost-effectiveness of transabdominal ultrasound for cervical length screening for preterm birth prevention. Am J Obstet Gynecol. 2013;209(6): 546.e1–e6.
  9. American College of Obstetricians and Gynecologists. Practice bulletin No. 130: prediction and prevention of preterm birth. Obstet Gynecol. 2012;120(4):964–973.
  10. Society for Maternal-Fetal Medicine Publications Committee; Berghella V. Progesterone and preterm birth prevention: translating clinical trial data into clinical practice. Am J Obstet Gynecol. 2012;206(5):376–386.
  11. Cervical Length Education and Review (CLEAR) guidelines. https://clear.perinatalquality.org. Published 2015. Accessed December 15, 2015.
References

  1. Saul LL, Kurtzman JT, Hagemann C, Ghamsary M, Wing DA. Is transabdominal sonography of the cervix after voiding a reliable method of cervical length assessment? J Ultrasound Med. 2008;27(9):1305−1311.
  2. Stone PR, Chan EH, McCowan LM, Taylor RS, Mitchell JM; SCOPE Consortium. Aust N Z J Obstet Gynaecol. 2010;50(6):523−527.
  3. To MS, Skentou C, Cicero S, Nicolaides KH. Cervical assessment at the routine 23-weeks’ scan: problems with transabdominal sonography. Ultrasound Obstet Gynecol 2000;15(4):292−296.
  4. Hernandez-Andrade E, Romero R, Ahn H, et al. Transabdominal evaluation of uterine cervical length during pregnancy fails to identify a substantial number of women with a short cervix. 2012;25(9):1682−1689.
  5. Friedman AM, Srinivas SK, Parry S, et al. Can transabdominal ultrasound be used as a screening test for short cervical length? Am J Obstet Gynecol. 2013;208(3):190.e1−e7.
  6. Rhoades JS, Park JM, Stout MJ, Macones GA, Cahill AG, Tuuli MG. Can transabdominal cervical length measurement exclude short cervix? 2015 Nov 2. [Epub ahead of print]
  7. Berghella V, Bega G, Tolosa JE, Berghella M. Ultrasound assessment of the cervix. Clin Obstet Gynecol. 2003; 46(4):947–623.
  8. Miller ES, Grobman WA. Cost-effectiveness of transabdominal ultrasound for cervical length screening for preterm birth prevention. Am J Obstet Gynecol. 2013;209(6): 546.e1–e6.
  9. American College of Obstetricians and Gynecologists. Practice bulletin No. 130: prediction and prevention of preterm birth. Obstet Gynecol. 2012;120(4):964–973.
  10. Society for Maternal-Fetal Medicine Publications Committee; Berghella V. Progesterone and preterm birth prevention: translating clinical trial data into clinical practice. Am J Obstet Gynecol. 2012;206(5):376–386.
  11. Cervical Length Education and Review (CLEAR) guidelines. https://clear.perinatalquality.org. Published 2015. Accessed December 15, 2015.
Issue
OBG Management - 28(1)
Issue
OBG Management - 28(1)
Page Number
52-51
Page Number
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Publications
MDedge ObGyn
OBG Management
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MDedge ObGyn
OBG Management
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Can transabdominal ultrasound exclude short cervix?
Display Headline
Can transabdominal ultrasound exclude short cervix?
Legacy Keywords
Vincenzo Berghella MD, transabdominal ultrasound, TAU, short cervix, cervical length, CL, preterm birth, PTB, spontaneous preterm birth, sPTB, vaginal progesterone, cerclage, ACOG, SMFM, transvaginal ultrasound, TVU
Legacy Keywords
Vincenzo Berghella MD, transabdominal ultrasound, TAU, short cervix, cervical length, CL, preterm birth, PTB, spontaneous preterm birth, sPTB, vaginal progesterone, cerclage, ACOG, SMFM, transvaginal ultrasound, TVU
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