I would have throttled anyone who took mine off me! Quick birth, no other form of distraction or pain relief, but I loved it - took the edge off the contractions and gave me something to do (using the boost) as the contraction peaked.
Have it as one weapon in your arsenal, ditch it if it's not working for you. I used Tens and hypnobirthing (natal hypnotherapy) for all 3 of my births and got to 9-10cm before feeling the need for gas and air. You do need to put it on early, if you wait until contractions are very painful it probably won't work.
I don't how useful they are for pain relief but they are a great distraction. I used mine for the first 18 or so hours before I could get into the pool and it took my mind off contractions (especially when dh had the controls!)
I totally agree with Shootthemoon above. I gave birth just using tens and nothing else. It mainly served as a distraction and actually took the edge off. I must admit that I did ask for additional pain relief when I got to hospital but to my dismay I was already fully dilated and gave birth 23 minutes later so there was no time. It was immensely helpful in the early stages, well worth it.
Helpful hint though - when I used it while giving birth to my first baby, I didn't tell anyone it was on and it interfered with the monitoring clip that they popped onto my DS's head. They tried three times and each one wouldn't work. After he was born and I was peeling the pads off my back we realised what the issue had been!
I hated mine, it was so irritating, I hired it from the hospital and had the proper Mamma Tens which has a boost button for contractions.
I did give it a proper chance and stuck it for the first 12 hours or so and finally ripped it off in a temper when I pressed the boost button for the millionth time and nearly shot through the ceiling!!
It didn't give me the slightest bit of pain relief, just an intense itchy, buzzing feeling but I've read that it is more of a placebo and there's no evidence of it taking off pain, it's a distraction and something to give you a bit of sense of control. Dd was back to back though and I don't know if that made a difference.
I got to hospital and was 9cm with just tens. Think I put it on a bit late but it definitely helped me. It also electrocuted DH when he took it off for me to get into the pool once we were at hospital, was quite funny and gave us all a laugh! These were the cheapest I could find and came well in advance. www.tens.co.uk
I was induced, had pessary in the evening and started contracting overnight. Put tens on right away and had an uncomfortable night bouncing away on a ball but didn't feel too bad. Strolled down to delivery suite in the morning to get waters broken and was 9cm! Midwife and doctor really couldn't believe it, their jaws actually dropped.
Unfortunately it all went downhill from there but I can't fault the tens, it was amazing!
I got to 6cm on a TENS machine. I took it off to get in the birthing pool and the SECOND the pads left my back I regretted the decision! If it wasn't for the fact that the midwives has taken 15 minutes to fill the huge pool, get it to the right temperature and light all the candles, I would have backed out and put the machine back on (so 'British', even in labour !) I hired mine from Mothercare and recommend it them to anyone who'll listen now
In the end I used mine as a missile to lob at xh, while swearing copiously. Mainly because in a transitional fuddle, I found myself stuffing the tens plunger into my mouth, instead of the g&a and squeezing on the g&a tube, rather than the plunger.
Ended up birthing with neither g&a or tens but it provided an amusing distraction in hindsight!
I had hoped to use birthing pool too, either as pain relief or for actual birth depending how I feel on the day, but it's good to know TENS machine seems worthwhile. Just got to wait to see when she arrives now!!