CERVICAL CANAL WIDTH

Visualization of the cervical canal allows for direct measurement of its width at the level of the internal os.

• Normal Pregnancy
• Mean width of cervical canal shows no significant change from 10-36 weeks of gestation (1,2).
• Cervical Incompetence
• A measurement of ³8 mm is diagnostic (3).
• Of the three measurements, cervical width is by far the most reliable parameter to predict cervical incompetence.

REFERENCES

1. Varma TR, Patel RH, Pillai U. Ultrasonic assessment of the cervix in normal pregnancy. Acta Obstet Gynecol Scand 1986;65:229-233.
2. Podobnik M, Bulic M, Smiljanic N et.al. Ultrasonography in the detection of cervical incompetency. J Clin Ultrasound 1988;16:383-391.
3. Varma TR, Patel RH, Pillai U. Ultrasonic assessment of cervix in at risk patients. Acta Obste Gynecol Scand 1986;65:147-152.