Second-trimester evaluation of cervical length for prediction of spontaneous preterm birth
- Vincenzo Berghella, MD
Vincenzo Berghella, MD
- Director, Maternal-Fetal Medicine
- Professor, Obstetrics and Gynecology
- Thomas Jefferson University
- Section Editors
- Charles J Lockwood, MD, MHCM
Charles J Lockwood, MD, MHCM
- Section Editor — Obstetrics
- Senior Vice President, USF Health
- Dean, Morsani College of Medicine
- Professor, Obstetrics and Gynecology
- University of South Florida
- Deborah Levine, MD
Deborah Levine, MD
- Section Editor — Imaging
- Professor of Radiology
- Director of Ob/Gyn Ultrasound
- Department of Radiology
- Beth Israel Deaconess Medical Center
This topic will describe the normal distribution of cervical length, provide a clinical definition for a short cervix, and discuss our approach and technique for cervical length screening.
Cervical shortening (effacement) is one of the first steps in the parturition process, preceding labor by several weeks. As cervical length decreases in the second trimester, the risk of spontaneous preterm birth increases [1-5], especially when effacement occurs early in the second trimester . Because effacement begins at the internal cervical os and progresses caudally [1,5], it is often detected on ultrasound examination before it can be appreciated on physical examination. The cause of preterm cervical shortening is often unclear. It has been attributed to several sources, including occult uterine activity, uterine overdistention, congenital or acquired cervical insufficiency, decidual hemorrhage, infection, inflammation, and biological variation.
NORMAL CERVICAL LENGTH
Normally, cervical length is stable between 14 and 28 weeks of gestation and is described by a normal, bell-shaped curve [1,7]:
●15 mm – 2nd centile
●20 mm – 5th centile
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- NORMAL CERVICAL LENGTH
- DEFINITION OF SHORT CERVIX
- CERVICAL LENGTH SCREENING
- Guidelines from national organizations
- Our approach to cervical length screening and intervention
- - Singleton, no prior preterm birth
- - Singleton, prior preterm birth
- - Singleton, no prior birth, but risk factors for cervical insufficiency
- - Multiple gestation
- SONOGRAPHIC MEASUREMENT OF CERVICAL LENGTH
- Online resources
- Quality assurance
- SUMMARY AND RECOMMENDATIONS
- Asymptomatic women