I can't open the links above because of my net nany at work. So I apologise if this is a repeat. Possible reasons for caesarean delivery include:
- prolonged labour or dystocia
- apparent fetal or maternal distress
- complications (pre-eclampsia, active herpes)
- catastrophes such as cord prolapse or uterine rupture
- multiple births (though this is controversial)
- abnormal presentation, (breech or transverse positions)
failed induction of labour
- failed instrumental delivery (by forceps or ventouse)
- the baby is too large (macrosomia)
- placental problems (placenta praevia, placental abruption or placenta accreta)
- contracted pelvis
- previous caesarean section
- prior problems with the healing of the perineum (from previous childbirth or Crohn's Disease)
Although some of those above can be deemed contraversial and different providers may disagree about when a caesarean is required. the United Kingdom, the law states that a labouring woman has the absolute right to refuse any medical treatment including caesarean section "for any reason or none", even if that decision may cause her own death, or that of her baby. Other countries have different laws.
Contrary to suffragettes answer, a caesarean section is a major operation, with all that it entails. Pain at the incision can be intense, and full recovery of mobility can take several weeks or more. A prior caesarean section increases the risk of uterine rupture during subsequent labour, so it is not an entirely 'convenient' option.