The opening of the cervix measured in centimeters, reaching 10cm for delivery.
What is Cervical Dilation?
Cervical dilation is the process of the cervix opening to allow the baby to pass from the uterus into the birth canal. While effacement is about thinning, dilation is about width.
Dilation is measured in centimeters (cm), ranging from 0 (closed) to 10cm (fully dilated or 'complete').
The Stages of Dilation
- Early Labor (0-6cm): Dilation usually progresses slowly. You might stay at 2cm or 3cm for several days before active labor kicks in.
- Active Labor (6-8cm): Contractions become much stronger and more frequent. The cervix typically dilates about 1cm per hour in this phase.
- Transition (8-10cm): The most intense phase. The cervix opens the final few centimeters, and the body prepares for the 'pushing' stage.
Visualizing 10 Centimeters
To give you an idea of the scale:
- 1cm: The size of a blueberry.
- 4cm: The size of an Oreo cookie.
- 7cm: The size of a tomato.
- 10cm: The size of a bagel or a small melon.
What Triggers Dilation?
The primary drivers of dilation are consistent, strong uterine contractions. Each contraction pulls the cervix slightly further open, using the baby's head as a natural wedge.
The Bottom Line
Dilation is the most famous metric of labor progress, but it isn't a race. Every body and every labor is different. Focus on your breathing and the support of your birth team, rather than just the number!
Medical Disclaimer: All content in this section is for educational and informational purposes only and is NOT intended as medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Bloom is not a replacement for professional medical consultation and should not be used as a primary form of birth control. Read our full Terms of Service.
Read on the go.
Healthy pregnancy, empowered choice. Download the free Bloom app to track your 9-month journey and beyond.