The cervical length ultrasound is a specific screening tool used in the second trimester to assess the length of your cervix, which can indicate a risk for spontaneous preterm birth. This test offers a clear picture of an important factor in your pregnancy, helping you and your care team make informed decisions.
What it is
Your cervix is the lower part of your uterus that connects to your vagina. During pregnancy, it typically remains long and closed until labor begins. A cervical length ultrasound measures the length of this cervix. The most accurate way to do this is through a transvaginal ultrasound, where a small probe is gently inserted into the vagina. This provides a very clear view of the cervix, allowing for precise measurement.
A short cervix, generally defined as less than 25mm between weeks 18 and 24 of pregnancy, is considered a significant risk factor for spontaneous preterm birth. Understanding this measurement can bring clarity and allow for proactive conversations with your provider about potential supportive measures. This is different from other screenings like the Glucose Challenge Test (1-hour) or Glucose Tolerance Test (3-hour), which focus on gestational diabetes, as the cervical length scan directly assesses a structural factor related to birth timing.
