I'm also a first timer, looking at an induction :( and wondering about an epidural. I plan to see how it goes but have one if it all gets too much (especially if I end up on syntocinon infusions).
The risks of an epidural are small, but definitely there. However the benefits are also great, when they work well.
Yes, the intervention rate is greater with epidurals (goes from about 7-14%) so not by any means 'most women' who have an epidural. The incidence of section is not increased (some old papers from a few decades ago have suggested this but times and epidurals have changed and more recent work challenges this). Ditto chronic back pain. You can be a bit sore or bruised in the back for a few days but long term back ache is just as likely with or without an epidural. Studies looking at thousands of women draw this conclusion.
There is a probably, as several pps have said, a correlation between increased intervention and epidurals. However this is NOT the same thing as causation. A big or badly positioned baby is more likely to result in a slower or obstructed labour, increased pain and augmentation. All of which mean a woman is more likely to request an epidural. However the epidural doesn't 'cause' the size of the baby, or it's position necessarily, but they are associated with it. On case-by-case basis it can be difficult to pick out the difference between the chicken and the egg... Again studies looking at large cohorts make the picture clearer.
Undoubtedly epidurals do cause some problems in some women. They can make it more difficult to feel to push properly, make you immobile, require continual foetal monitoring and make you itchy and shaky. And they take a while to wear off. The effect on the baby is however very small and in fact returning some physiological normality to the mother by reducing her pain can also reduce stress markers in the baby (Felicity Reynolds, a very well respected obstetric anaesthetist) has published on this).
From reading some posts, it's clear that there is sometimes confusion between an epidural for labour, an epidural that is 'topped up' for surgery and a spinal anaesthetic. They all involve a needle in the back but they are not the same and have different side effects. An epidural purely for analgesia in labour uses a much weaker solution. Yes, if it's in for hours your legs will undoubtedly get very heavy, but not in the same way that a spinal for theatre will. Labour epidurals also often wear off much more quickly.
It's easy to blame an epidural for bladder/pelvic floor problems (it seems to make sense...) but again, having a long labour with a baby's head crushing the nerves that supply such areas against your pelvic brim and stretching the muscles if your pelvic floor, especially if an intrumental delivery is involved, is much more likely to cause such problems. Catheters are inserted because your bladder goes numb too and you can't tell if you need a wee. An overdistended bladder is not good. Catheters themselves per se don't cause problems (potentially a route for infection but not causing nerve damage).
About 15% of epidurals don't work completely. There isn't always an obvious reason (and to be honest it's bloody amazing the ever work at all - google epidurogram- it's a jungle in there!). And there are risks of nerve damage that gets better (1/2000) that is permanent (1/10000) and paralysis (1/200000) and post epidural headache (1/100). The vast majority if headaches will be due to dehydration/tiredness/hormones/screaming baby though - not the epidural!
So I suppose in summary they aren't perfect, some women don't like the fairly common side effects (numb legs and not being able to feel to push so well - but that doesn't mean it can't be done) and there are some really very small risks of more serious complications. They don't cause all the bad things they're commonly accused of though by quite a stretch.
For many women they are an absolute godsend and turn a hideous terrifying time into something much more manageable.
I'd plan to not have one if I don't need but definitely go for it if I do.
Oh - and having seen many hundreds of women after an epidural, the vast majority say thank you, they'd have one again please, a few say thanks but no thanks (usually because of mobility or incomplete pain relief) and a very very few actually have long term problems that are very clearly the result of the epidural alone.
The obstetric anaesthetist website has a very good, up to date section on epidurals for those of you wanting references and further info.