A cervical ultrasound uses high-frequency sound waves to create detailed images of the cervix, the lower, narrow part of the uterus that connects to the vagina. This specialized scan helps assess its physical characteristics.
Appearance of a Healthy Cervix
On an ultrasound, a healthy cervix typically appears as a cylindrical structure when viewed longitudinally. Its average length in non-pregnant individuals is about 2.5 to 3 centimeters, with a width of approximately 2.5 centimeters. During pregnancy, the cervix can measure around 4 centimeters until about 37 weeks of gestation. The tissue generally presents with a uniform, homogeneous texture, similar in appearance to the surrounding uterine muscle.
The endocervical canal, which runs through the center of the cervix, is visible as a distinct echogenic line. This line represents the interface between the anterior and posterior mucosal layers within the canal. While both transabdominal and transvaginal ultrasound methods can visualize the cervix, a transvaginal approach, where the probe is inserted into the vagina, often provides more detailed and accurate images due to its closer proximity to the cervix.
Common Variations and Benign Findings
Ultrasound examinations often reveal benign findings. Nabothian cysts are a common example, appearing as small, round, fluid-filled sacs. These cysts usually have smooth borders and lack internal solid components or blood flow. They typically measure a few millimeters to 1 or 2 centimeters, although they can occasionally be larger.
The length of the cervix can also show minor variations across the menstrual cycle, which are considered normal physiological changes. Slight differences in the cervix’s overall shape are also common and fall within the range of normal variation for individuals. These findings are generally not a cause for concern and are often asymptomatic.
Indications of Potential Concerns
An ultrasound can reveal specific visual cues that may indicate a potential issue requiring further evaluation. One such finding is the shortening of the cervix, which is particularly relevant during pregnancy. A cervical length measuring less than 2.5 centimeters before 24 weeks of pregnancy can suggest an increased risk of preterm birth. This shortening might also be accompanied by “funneling,” where the internal opening of the cervix begins to widen.
Cervical polyps, which are growths within the cervical canal, can also be identified. These typically appear as well-defined masses protruding from the cervical wall, and they may be either hyperechoic (brighter) or hypoechoic (darker) than the surrounding tissue. Doppler ultrasound can sometimes show a feeding vessel, indicating blood supply to the polyp. The presence of fibroids or other masses in the cervix will appear as distinct areas with different textures or shapes compared to normal cervical tissue.
Signs of inflammation or infection might be observed through subtle changes in the tissue’s texture, such as a diffuse hypoechoic appearance, or the presence of fluid collections within or around the cervix. Such findings often prompt additional medical assessment to determine the underlying cause and appropriate management.
Reasons for Cervical Ultrasound
A cervical ultrasound is performed for various clinical reasons, providing valuable information about the health of the cervix. During pregnancy, it is commonly used to monitor cervical length, especially in individuals with a history of preterm labor or other risk factors. This monitoring helps assess the risk of early delivery and guide interventions if necessary.
The scan is also used to investigate symptoms such as abnormal vaginal bleeding, which can be caused by various conditions affecting the cervix or uterus. Persistent pelvic pain is another common indication for a cervical ultrasound, as it can help identify potential structural causes of discomfort. Furthermore, in cases of fertility issues, a cervical ultrasound can assist in evaluating the cervical canal for any anatomical variations that might impact conception. It may also be used as a follow-up measure after abnormal Pap test results to further examine the cervical tissue.