There is no evidence to confirm that epidurals cause backache. Large studies of women in labour have shown no difference in backache between those that had, and those that didn't have an epidural. What can cause backache, however, is pregnancy and labour! Epidurals get a lot of blame for back pain following delivery. Some of this may be positional. This is because in labour you may twist into a position that causes strain or injury but you are unable to feel this at the time, only afterwards.