It's a topic barely touched on in antenatal classes, and unless you're having a planned one, something you may not want to think about.

But as almost a quarter of all births in the UK are by Caesarean section, it's worth finding out what they entail.

Who will need one?

The vast majority are due to medical reasons. Says Peter Bowen-Simpkins, consultant gynaecologist and spokesperson for the charity WellBeing of Women: 'We would probably plan a C-section if your baby is in a breech position; if the placenta is blocking your cervix (placenta praevia); if you've had a previous Caesarean, or if you have too small a pelvis for the baby to get through.

'You may also be considered for an elective C-section if you've had a traumatic previous delivery - for example, a really bad tear or a difficult forceps delivery.'

Emergency Caesareans

All C-sections performed once labour has begun are classified as 'emergencies'. The most common reason for an emergency Caesearean is that labour has failed to progress - contractions have stopped or your cervix has stopped dilating, for example.

Life-threatening reasons for a C-section are a cord prolapse, where the cord has slipped through your cervix, threatening your baby's blood supply; or a placental abruption, where the placenta has come adrift.

Foetal distress, indicated by abnormalities in the baby's heartbeat, lack of success with ventouse or forceps, or a failed induction can also lead to a Caesarean.

What to expect

You will be given a pair of surgical stockings to wear which will help prevent the formation of blood clots. Nail varnish will be removed, jewellery will be removed or taped up, and your pubic area will be shaved.
In theatre, you'll be given a spinal block anaesthetic or your epidural will be topped up. Your partner will be asked to wear a surgical gown but will generally be allowed to stay with you.
The anaesthetist will ensure you cannot feel anything before the operation begins.
A screen is clipped up so you can't see what is going on, a catheter will be inserted, and an incision made just above your bikini line giving the surgeon access to your womb.
You may feel a tugging or rummaging sensation but no pain. The baby will be delivered within three to five minutes of the incision, he will be lifted out, checked and the cord clamped and cut.
If everything is OK, you will be able to hold your baby on your chest while the placenta is delivered and you are stitched up. You may prefer your partner to hold the baby while this is completed.
The whole operation takes around 30 minutes. You will then be removed to a recovery bay or room and then onto a ward. A midwife will encourage you to breastfeed your baby as soon as possible.

After the Caesarean

Your catheter will usually be left in place until the morning after the operation. You will also have a small drip running into an arm vein, and your surgical stockings will be left on.
You will be given painkillers but your midwife will encourage you to get out of bed as soon as possible, to promote circulation and help prevent thrombosis.
Expect to stay in hospital for around 3 days and arrange to have extra help at home as you may find getting around difficult at first.

What about the next baby?

You are recommended to wait at least 12 months before having another child after a C-section. You can give birth naturally after a C-section, but many women find they are offered a planned Caesaerean second time around. There is a one in 200 risk that your scar will rupture during labour, requiring an emergency Caesearean.

Talk to your doctor and midwife if you are keen to have a VBAC (vaginal birth after Caesarean).