effacement
The thinning and shortening of the cervix during labor, measured as a percentage from 0% (thick) to 100% (paper-thin).
Full Definition
Effacement refers to the progressive thinning and shortening of the cervix that occurs during late pregnancy and labor. The cervix normally measures 3-4 cm in length, and effacement describes how much it has shortened, expressed as a percentage. At 0% effacement, the cervix retains its full thickness, while 100% effacement indicates the cervix has thinned to become flush with the uterine wall. This process often occurs simultaneously with cervical dilation and is a key indicator of labor progression. Effacement is assessed during vaginal examinations and documented in labor notes.
Usage
Usage note: Always express as a percentage; distinguish from dilation which measures cervical opening width.
In Context
- "The patient's cervix showed 80% effacement with 4 cm dilation on examination." — Labor and delivery record
- "Complete effacement was achieved before active labor commenced." — Nursing progress note