There are a number of medical reasons for carrying out a caesarean section.
In an emergency situation there may not be time to fully discuss the options for caesarean section, but it could be a lifesaving procedure.
Sometimes it becomes apparent before labour that a caesarean section will be the safest method of delivering the baby. In some cases an un-planned emergency caesarean will be carried out during labour.
A doctor may decide to carry out a caesarean section if:
 You suffer from severe pre-eclampsia (high blood pressure due to being pregnant)
The unborn baby is lacking oxygen
Labour is not progressing quickly enough, causing the mother or baby to feel distressed
If you are expecting twins or other multiple births. In this case a vaginal birth is more difficult as the babies may be premature; one or more of the babies may be in an abnormal position; or two or more of the babies may share a placenta. If a placenta is being shared, a caesarean section is necessary to avoid the babies being deprived of oxygen.
Labour has been induced for a medical reason but contractions aren't effective enough for a vaginal delivery
An x-ray or scan has shown that the baby will not fit down the birth canal - either it is too big or it is in an abnormal position
The placenta is blocking the exit to the womb (placenta praevia)
You are infected by a virus, like genital herpes or HIV, which may pass to the baby in a vaginal delivery
You go into labour prematurely. An emergency caesarean section will prevent possible trauma to the delicate head of the premature baby as it travels through the birth canal.
You suffer from certain medical conditions, such as a heart problem, that would put your health at risk in a vaginal delivery.
Women over the age of 35 are more likely to suffer complications if they have a vaginal birth. This is because they are more likely to have high blood pressure or gestational diabetes, and there is a higher chance that the cervix will dilate slowly.
May 2011 | 
Introduction to Caesareans
