C'smumma, the anaesthetist explained to me that when they try to do either a spinal or an epidural, there are a small number of ppl whose back joints are shaped a bit differently (normal for them of course) or sometimes there's this membrane that's in a different place to most ppl, which can make the epidural uneffective, usually it only numbs one side of the body.

Also, sometimes because the spinal is a single dose medication, if the dose is not quite right (either too much or too little) they can't re-do it and you will then need a general. I understand that's pretty rare.

Agadoo, you can have a CS under a general but it's generally considered not the best scenario because women struggle to cope with the birth transition, they wake up and there's this baby there. It's also harder to give mum and baby time together immediately after birth because it's so much more medicalised. The general surgical risk factors are higher under a GA too. However I believe that there may be some circumstances where a Dr would agree to do the CS under general as that was one of the options presented to me on the basis of my previous birth trauma.