I'm not having twins, but I have been having regular, painful contractions with bowel loosening and loss of mucus plug. All the classic signs of preterm labour. The only thing that made it OK was doing exactly what the ladies above recommended - lying down for a long while, drinking buckets of water, relaxing. Extremely difficult to do as I have a two-year-old and we were weeks then days away from moving, but better that than it developing into true preterm labour! I basically put myself on modified bedrest for a few days, because every time I would get up to do anything I would start getting contractions again. I've been doing a lot of relaxing after the move too, because I've been sick, so we'll see how the uterus does once I'm up and about unpacking and nesting.
I have talked to my midwives about it, both over the phone at the time and at my latest appointment, and they were mildly concerned, but mostly not, as they went away after resting. But I don't have twins with other stuff going on, so I'd probably call.
Follow Mothering