I rung the lead midwife to get her opinion and she has said they were totally wrong to say that to me. As I can give birth naturally with or without sciatica. If they feel that during the birth things aren't going well then they'll refer me to have a c section but until then they won't.
She was so disgraced by the midwives saying that, that they have changed my midwife team.
Thank you all for your replies