Cervical Length Assessment and Preterm Labor

Assessing the likelihood of preterm labor has always been an important part of ultrasound examinations. Reason being is that premature births are the cause of nearly 70% of neonatal/fetal deaths. Although only about 12% of births in the United States are preterm and occur before 37 weeks, this is still a very prominent issue for technicians and physicians today. Furthermore, when a mother carries twins or triplets the risk of preterm pregnancy jump to nearly 55% and 94% respectively. 

There are a variety of factors that can increase a woman’s risk for preterm labor; these include high blood pressure during pregnancy, chronic conditions such as heart disease or diabetes, being younger than 17 years old, smoking or using street drugs, and previously having a preterm baby. However, there is a better way than just taking note of these factors, it's the cervical length assessment. 

Ultrasound Images

Methods have ranged from transabdominal to translabial or trannsperineal, but transvaginal has since become the most widely adopted and accurate method for cervical length assessment. With this approach there is no need to expand the bladder (leading to cervical lengthing) like in the transabdominal method and we get a much clearer image than the translabial approach without the bowel gases being an issue. The risk for preterm labor is inversely correlated to cervical length so it’s imperative that the image is clear and the measurements are accurate.

Waiting Room

This is means the shorter the length of the cervix, the greater change of preterm labor. The presence of a “positive predictive value” such as a measurement of 25mm is taken into account along with the patient’s pretest probability factors (high blood pressure, diabetes, etc.). If the pretest risk factors confirm a risk for preterm labor, the physician and patient can then take the proper precautions to prepare for preterm labor such as therapeutic regimens.

This can be a complicated puzzle to solve as no one factor is a direct cause of preterm labor, but by continuing to evolve our methods of assessment, we can better serve those 12% of patient’s. That’s why we are particularly excited for the initiatives being taken in our community right now.

Coming soon with be the Preterm Labor Assessment Training where we are looking forward to working with The University of Texas Dell Medical School as we educate and train physicians, sonographers, and nurses alike on The March of Dimes Preterm Labor Assessment Toolkit on March 28th. As a part of our core values, we believe this to be an important event for healthcare professionals as we continue to educate others and learn how to the deliver premium care to all women.