First signs of labour
Every labour and birth is unique, and there is a very wide range of experiences to be had. You can't predict exactly how or when your labour will start.
Look for these signs:
The show
This is the release of the mucus plug (the operculum), which seals the opening of the cervix. It might be a blob of pinkish jelly; or it could be a series of smaller pieces; the colour could be more red than pink. The plug 'escapes' because the cervix is just starting to stretch and soften - but it doesn't mean anything has to happen now. It could mean labour will start anything between a couple of hours and a few days.
Rupture of the membranes or 'breaking of the waters'
The membranes are the bag of waters, or amniotic sac, which hold the amniotic fluid surrounding the baby. When the membranes rupture, the amniotic fluid (known as liquor – pronounced 'ly-kwor') comes out. It can happen as a sudden gush of liquid, but it's more usually a slow trickle. Call your midwife or the hospital if you know your waters have broken, and ask for advice. They may suggest you come in – there is a possible risk of infection if the waters break and the baby takes too long to be born. There's also a risk if your baby's head isn't engaged in the pelvis, as the waters could bring the cord down as well. This could mean your baby might compress it – and that could mean a risk to your baby's oxygen supply. Most women whose waters break go on to have perfectly normal labours, and fairly soon afterwards, too.
Contractions
Count them and time them. If the contractions come closer together over a period of an hour or two, and last longer than 40 seconds, and get stronger, they're likely to be labour contractions.