The Purple Line: A Fascinating Sign of Labour Progression
The Purple Line: A Fascinating Sign of Labour Progression
Have you ever heard of the “purple butt line”?
It’s a fascinating, lesser-known physical sign that may appear as your body transitions from pregnancy into labour. Some people notice a faint purple or reddish line running from the anus up between the buttocks, a natural response to the changes happening in the pelvis as labour begins and progresses.
This line, sometimes called the “purple butt line,” is believed to appear as the pelvic tissues stretch and pressure and blood flow increases while the baby moves down through the birth canal. Midwives and birth professionals have observed that, for many birthing people, the length of this line tends to increase as the cervix dilates, offering a potential, non-invasive indicator of labour progression.
The Purple Line Theory
Traditionally, cervical dilation is checked manually through vaginal examinations. The purple line theory offers a gentler alternative, suggesting that observing this line might help track dilation without internal assessment.
While not every person develops the line, studies have shown a moderate correlation between its length and the level of cervical dilation. This has led many midwives and birth professionals to use it as an additional observation tool, especially during home births or midwifery-led settings.
It’s important to note that the purple line isn’t a precise measurement or diagnostic tool. Instead, it’s one of several cues that can provide insight into how the body is adapting and progressing during labour.
How to Recognise It
The purple line often begins near the anus and gradually extends upward as labour progresses. It may be faint or bold, and while it’s more noticeable for some, it can be difficult to see for others.
Because it’s located in an area that’s hard to view yourself, a birth partner, midwife, or doula may be best placed to observe it.
3–6 cm purple line → approximately 1–2 cm dilated
5–8 cm purple line → approximately 3–6 cm dilated
7–9 cm purple line → approximately 7–8 cm dilated
8–11 cm purple line → approximately 9–10 cm dilated
Why It’s Helpful
Understanding the body’s visual and physical cues can help you feel more connected and confident during birth. The purple line can act as a reminder of your body’s incredible design, showing that progress is happening, even when you can’t see or feel every change.
Please note
It’s important to note that this line appears in approximately 76-86 % of birthing people. However, cervical dilation can begin days or even weeks before birth for some, while for others, it may occur just hours before the baby arrives. So, while the purple line is a fascinating and insightful indicator of progress, it isn’t a reliable way to predict when your baby will be born.
At Tugun Osteopathy, we love exploring and educating about the physiology of birth from pelvic mobility and breathwork to understanding signs like the purple line. These insights empower birthing people to approach labour with trust, awareness, and calm.
Whether you’re planning a hospital birth, home birth, or anything in between, learning about these physiological cues can help you feel more confident and informed throughout your birthing journey.
If you are after further birth support we are always here to help you, contact us at any time on 0405 640 786.