I am reading Alternative Maternity by Nicky Wesson and thought I would share this.
'This provides the most convincing evidence that labour has started. If you are accustomed to feeling your cervix regularly you will be in a good position to notice the way it changes towards the end of the pregnancy. A ripe cervix, one that is ready for labour, feels soft & malleable, more like your lips to touch than your nose. If will have become softer, shorter and thinner and you may be abel to get your finger in easily.
If you think you are in labour you can make sure by feeling your cervix. You MUST wash your hand thoroughly first. If your servix is high or you can't reach it, you are unlikely to be in labour because the cervix descends and becomes easier to reach as it dilates. At this point, if it's accessible, it will feel as if the edges are frayed. It may feel wobbly and you might be able to get two fingers inside.
When you are definitely in labour, the baby's head moves down and you will feel the cervix lower in your vagina. There will be nothing left of the canal of the cervix, it will have been taken up into the body of the uterus so that all that remains is the tissue stretched over the head, with the os or opening gradually getting wider. At this stage it may feel like something slimy over a grapefruit. It may stretched taut so that you are unable to get your fingers inside it, or you may feel the plastic like membrenes with the amniotic fluid behind them. The hole left by the dilating cervix is completely round and once it is fully dilated (10cm) there is no rim of cervix left at all.