6 facts to know about cervical dilation

What happens when your cervix opens up for baby’s birth, plus, learn safe ways to speed up this crucial process!


When it comes to labour and giving birth, one of the top concerns for most, especially first-time, parents is how to tell if you’re in labour?

You may probably may have heard about painful contractions and how these will progressively become higher in both frequency and intensity as your kewpie is actually about to arrive. Yet another equally important aspect of vaginal birth ― cervical dilation ― happens inside your body.

As labour progresses, your cervical wall actually opens or widens in a process called dilation to accommodate your newborn, so that he can travel down the birth canal. However, many mums-to-be may not even know they are fully dilated because they may not feel anything “down there”.

Dr Chong notes on average first time mums will take about an hour per centimetre of dilation, so that works out to be about 10 hours.

SmartParents expert and ob-gyn at Gleneagles Hospital, Dr Christopher Chong and ob-gyn Dr Peter Chew lists important facts you need to know about this vital birthing process…

1) Cervical dilation tells you which stage of labour you’re in…

Once you’re on the hospital bed, the nurses will come in to do a routine vaginal exam. This lets them know which stage of labour you’re in. Dr Chew explains “You are in the early labour phase when your cervix is stretched up to 3cm. Active labour begins from 3 to about 7cm and moves into the transition phase when the cervix is fully dilated at 10cm.”

Besides the opening that gradually widens, the consistency of your cervical wall also changes — through a process called effacement — as labour progresses. The walls feel thick and firm to the touch at the beginning of labour and slowly softens, shortens and becomes thinner closer to birth.

2) … but it doesn’t tell you how long you’ll still need to wait

Unfortunately, the time taken for your cervix to expand fully can differ from one person to the next. Dr Chong notes that first-time mums, on average, will take about an hour per centimetre of dilation, so this works out to be about 10 hours.

The cervix of women who have had previous vaginal births separate sooner in subsequent deliveries. Dr Chew explains, “For these women, the cervix dilates faster at about 1.2 to 1.5cm per hour.”