ultrasound

Cervical Length Scan

Transvaginal ultrasound measuring cervix length to assess preterm birth risk.

📅 When Performed

Weeks 18-24, may be repeated

⏱️ Results Timeline

Immediate

Overview

A cervical length scan uses transvaginal ultrasound to measure the length of your cervix. A short cervix can indicate increased risk of preterm labor and delivery.

The cervix should remain long and closed during pregnancy. If it starts to shorten too early, it may not stay closed until term. This is called cervical insufficiency.

This scan is typically done for women with history of preterm birth, previous cervical surgery, or unexplained pregnancy loss. If cervix is short, interventions like progesterone or cerclage may prevent preterm birth.

🎯 Purpose of Test

  • •Assess risk of preterm birth
  • •Detect cervical insufficiency
  • •Monitor women with history of preterm labor
  • •Determine need for interventions (progesterone, cerclage)
  • •Identify women who need closer monitoring

🔬 How It's Performed

  1. 1.Transvaginal ultrasound (probe inserted in vagina)
  2. 2.Empty bladder before scan
  3. 3.Measures cervix length in millimeters
  4. 4.Checks if cervix is opening (funneling)
  5. 5.Takes 5-10 minutes
  6. 6.May be repeated every 2-4 weeks
  7. 7.Performed by trained sonographer

👀 What to Expect

  • →Similar to early pregnancy ultrasound
  • →Transvaginal probe inserted gently
  • →Painless but may be slightly uncomfortable
  • →Very quick scan
  • →Immediate results
  • →If short, discuss treatment options
  • →May need serial scans to monitor

✓ Normal Results

Cervical length 30mm or longer at mid-pregnancy

⚠️ Abnormal Results

  • •Short cervix (less than 25mm at 18-24 weeks)
  • •Funneling (cervix opening from inside)
  • •Need for progesterone supplementation
  • •May need cerclage (cervical stitch)
  • •Activity restriction or modified bed rest
  • •Increased risk of preterm delivery
  • •Need for closer monitoring and follow-up scans

⚠️ Risks & Considerations

  • •No risks - safe transvaginal ultrasound
  • •Slight discomfort from probe
  • •Anxiety about results

📝 How to Prepare

  • →Empty bladder completely before scan
  • →No other special preparation
  • →Quick appointment
  • →Discuss risk factors with provider beforehand

Related Tests

← View All Pregnancy Tests