At 33 weeks, I was in pre-term labor due to dehydration and stress from a car accident. Luckily, LO's heartbeat was steady. They gave me medicine to stop the contractions and hooked me up to an IV to hydrate me (I was up all night running to the bathroom to pee). I was closed when I went in, but they could feel a difference when they re-checked later. I don't remember the numbers, it was 3 years ago and that whole day is a blur for me. I was just kept overnight.
They sent me home with instructions to take it easy and stay hydrated.
I didn't have any serious contractions as long as I paid attention to my body and chugged water like mad. I didn't go on bedrest.
My water broke prematurely at 36w4d, and I had a healthy baby the next day. If my water hadn't broken, it's likely my body would not have started labor for awhile yet. I didn't even have contractions I could feel until my water broke and when I went in after about 1-2 hours after my water broke (waiting for babysitters), I was barely 3cm.