I think it starts at 13 weeks, yes Shawnie.
Logans mama, a TENS (Transcutaneous Electrical Nerve Stimulation) machine is a little machine which is attached by tiny wires to 4 sticky pads that stick on your back. When you have a contraction, you turn the little dial up however's comfortable for you. It delivers small electrical pulses which are sent to your nervous system where your brain sends out natural endorphins to block the pain. It feels a little bit like pins and needles, but doesn't hurt at all (unless you do what my mum did and turn it right up to the maximum by mistake!!) Lol. I highly recommend them. I have heard though that they are only helpful if you start using them straight away when you first start getting contractions. Also you can't use them in water for obvious reasons, so you can't use them in a birthing pool.
You can hire them from most places. I hired mine from boots for about £25 for 4 weeks. I'm definately using one this time.
xxx