Stages of labour

Labour begins as a hormonal response, probably to triggers from the baby's adrenal gland. This prompts your uterus to start contracting under the influences of these hormones. Your waters may break before this happens, or afterwards, or even at the end of labour.

If you're induced (when labour's brought on medically), hormones are administered as a drip which delivers the hormones into your bloodstream, or in a pessary inserted in your vagina. These act directly on the uterus to stimulate contractions.

The purpose of the contractions is to open your cervix and to help push your baby down the birth canal (vagina) and be born. At the start of labour your cervix is barely open (known as dilated). Over the next five to 15 hours or so it dilates completely to enable the baby’s head and body to descend.

Stage one

The baby is pushed downwards and almost reaches the end of the birth canal, with the head (usually) in a position be born first.

During this stage, each contraction gets closer to the previous one and lasts longer. This means labour gets faster as it progresses: it usually takes more time go from being 1cm or 2cm dilated to 5cm or 6cm dilated, than from 5cm or 6cm to 10cm (fully dilated).

A typical pattern is to experience one contraction of about 40 to 50 seconds every ten minutes at the beginning of stage one, and one contraction lasting more than minute and coming every 30 seconds or so at the end. By this time, the cervix is fully open and wide enough for the final descent and birth of your baby's head.

During this stage it helps to stay mobile and to be somewhere you can experiment with different positions, such as leaning against something or getting on all fours.

Slow progress?

Labour isn't always smooth and progressively intense. At times, contractions may slow down or even cease. If you and your baby are fine, you needn't worry. Just be patient, calm and prepared to walk around or move into a different position, while you wait for them to start again.

If contractions slow for a long period of time and it's thought you and/or your baby might benefit from things being helped along, you may be advised to agree to:

• Stimulation of contractions with a hormone drip (usually a synthetic oxytocin called syntocinon)
• Artificial rupturing of your membranes (ARM), the technical term for breaking the waters around your baby

The drawback is they can bring on very strong contractions, which you may find difficult to cope with.

Stage two

This is the birth of your baby and is usually a lot shorter than the first stage. Times vary: it can be very quick, lasting just a few minutes, or take more than two hours. It can be hard work, too, as you're actively pushing the baby out, bearing down and contributing your own efforts to help your body do its work.

The second stage begins when the cervix is fully dilated (10cm) and you feel a very strong urge to push downwards into your pelvis, although if you've had an epidural you might not feel this urge. If this is the case, your midwife will tell you when to push.

Pushing might be guided by the midwife, who can see what's happening. She might ask you to withhold some pushes, to coordinate them with your breathing, or to breathe through some of the urges. This can help prevent a tear in your perineum, which might happen if the baby comes out too quickly.

Your baby's head will usually emerge first, which is known as crowning. A couple more contractions and the head will be born, usually facing towards your back. Your baby's shoulders and head will then turn sideways. The baby is then fully born. The umbilical cord is usually clamped and cut at this stage. All being well, you'll then be given your baby to hold.

Stage three

This is the delivery of the placenta, which takes 15 to 30 minutes. You may not be very aware of it happening, as most of your attention will be on your baby.

As your baby's born, you may be given an injection of a synthetic hormone, usually in your thigh or buttock. The midwife should ask your consent before she does this. It stimulates the uterus to contract, which causes the placenta to come away from the uterus.

You might be asked to give a push or two, just as you did in stage two, to help it down, and the midwife might help with a process called 'controlled cord traction' - she places one hand on your abdomen, while the other hand keeps the umbilical cord taut.

The placenta peels away and the blood vessels on the inside of the uterus close themselves, which stops most of the bleeding (some bleeding is normal).

Some mothers opt for a 'physiological' or natural third stage. This means the uterus contracts by itself, and expels the placenta and membranes. The cord is clamped and then cut when it stops pulsating, after the placenta is delivered.

If this is what you'd prefer to happen, ensure it's in your notes or is part of your birth plan. There are some situations in which it might not be considered safe - if you're at risk of haemorrhage, for instance, or have a problem with blood pressure.