cervical length
Sonographic measurement of cervical dimensions used to assess preterm birth risk during pregnancy.
Full Definition
A transvaginal ultrasound measurement of the cervix from the internal to external os, typically performed between 16-24 weeks of gestation to assess risk of spontaneous preterm birth. Normal cervical length is generally >25mm, with measurements <25mm indicating increased preterm birth risk and <15mm indicating very high risk. The measurement technique requires specific protocols including proper probe placement, adequate cervical visualization, and multiple measurements over several minutes. Short cervical length may prompt interventions such as progesterone supplementation or cervical cerclage placement in appropriate candidates.
Usage
Usage note: Always document measurement technique and any cervical changes observed.
In Context
- "Cervical length measurement of 18mm at 20 weeks prompted initiation of vaginal progesterone." — High-risk pregnancy management
- "Serial cervical length monitoring showed stable measurements throughout the second trimester." — Preterm birth prevention protocol