11/12/2025
Have you heard of the “Purple Line” in Labor? 🤰
Did you know a laboring woman’s body sometimes gives visual outward clues about how labor is progressing? One of the lesser-known signs is the *purple line*: a faint line that can appear between the buttocks & rise upward as baby descends.
Baby’s descent & cervical dilation cause vascular congestion in the area, creating that purplish tint (can also be red, brown, blue, black or pink).
While it’s not present for everyone, & it’s not used alone to make clinical decisions, the purple line can be a helpful, non-invasive indicator of dilation and labor progress. It can be checked quietly while mom is on all-fours or side-lying without needing to be checked internally, keeping cervical checks to a minimum, and not interrupting the birthing woman’s flow.
Some key points to know:
💜 The purple line is thought to appear in up to 75–85% of labors.
💜 It tends to rise as dilation increases.
💜 It’s painless and simply a physiologic response — nothing to be worried about.
💜 It can be informative and helpful for women who want to minimize vaginal exams.
How to read it:
✨ At the start of labor, the line may be faint or low.
✨ As dilation increases, the line often rises upward.
✨ Near full dilation, it may extend higher along the sacrum.
Birth team can use it:
✨ As a quick, non-invasive check when vaginal exams are being limited
✨ To detect trends: Is pressure increasing? Is labor intensifying?
✨ To gather context alongside contractions, vocalizations, and movement.