What is a Cervical Length Scan?

The Cervical Length Scan is a vital diagnostic tool during the second trimester, especially for women at risk of preterm labour. Conducted between 16 and 24 weeks, it measures the cervix’s length and identifies signs of cervical insufficiency. Early detection allows for timely interventions, improving the chances of carrying the pregnancy to term.  

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What is Cervical Insufficiency?

The cervix is the lower part of the uterus that opens into the vagina. In women with Cervical Insufficiency, the cervix dilates or shortens too early in pregnancy, or opens without contractions, increasing the risk of preterm labour or miscarriage. Weakened cervical muscles cause an incompetent cervix. As the baby grows, increased pressure on the cervix may cause it to open too early if it lacks the strength to stay closed. Symptoms like pelvic pressure, backache, abdominal cramps, or changes in vaginal discharge could indicate this condition. Women with prior cervical surgery, uterine abnormalities, or a history of painless cervical dilation are at higher risk. If you notice these symptoms or suspect an issue, consult your OB-GYN. However, some women with an incompetent cervix may experience no symptoms.

How is cervical Insufficiency Diagnosed?

A cervical length scan helps diagnose cervical insufficiency by measuring the length of the cervix through transvaginal ultrasound, typically between 16–24 weeks of pregnancy. Doctors often suspect the diagnosis during the first pregnancy when it occurs but confirm it if it recurs in subsequent pregnancies.

• A cervix shorter than 25 mm is a key indicator of insufficiency.
• The scan also detects funnelling, where the internal portion of the cervix begins to open.

Early diagnosis allows timely interventions like Cervical cerclage or progesterone therapy to improve pregnancy outcomes.

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Why and When is the Cervical Length Scan Needed?

The Cervical Length Scan is particularly important in the following situations:

• History of Preterm Birth or Late Miscarriages: To monitor and manage cervical insufficiency.
• Multiple Pregnancies: Increased strain on the cervix raises the risk of premature labour.
• Cervical Surgery or Procedures: Procedures like a cone biopsy can weaken the cervix.
• Symptoms of Preterm Labor: Such as pelvic pressure or changes in vaginal discharge.

 

Importance of the Cervical Length Scan for Pregnant Women:

1. Identifying the Risk of Preterm Birth:

• A short cervix (less than 25 mm) is a known risk factor for preterm labor, which can lead to complications such as low birth weight, underdeveloped organs, and increased neonatal morbidity.
• The scan enables early detection of cervical shortening, helping prevent premature delivery.

2. Monitoring High-Risk Pregnancies:

• Women with a history of preterm birth, miscarriages, or uterine surgeries are at higher risk of cervical insufficiency.
• For such women, regular cervical length scans are crucial to monitor cervical changes and plan interventions.

3. Guiding Preventive Measures:

• If the scan reveals a short cervix, medical interventions can be planned:
  • Cerclage Procedure: Stitching the cervix to keep it closed during pregnancy.
  • Progesterone Therapy: Medications to strengthen the cervix and reduce the risk of preterm labor.
  • Lifestyle Adjustments: Recommendations like avoiding heavy lifting or prolonged standing.

4. Monitoring Women with Multiple Pregnancies:

• Women carrying twins or higher-order multiples are at a greater risk of preterm birth, and this scan is critical for ensuring timely management.

5. Reassurance in Low-Risk Pregnancies:

• For most women, a normal cervical length provides reassurance and helps healthcare providers focus on other aspects of pregnancy care.

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