actually, all mammals can stop labor. If you happened upon a doe in labor, she would leap up, run away and not resume contractions until she felt sure you were nowhere nearby.

And I can personally testify to the fact that worry stops labor. I was totally in labor when I got to the hospital with my first: water leaking, contractions 5 minutes apart and painful...but after waiting 45 minutes in the emergency room lobby for them to get a wheelchair down to bring me up to L&D, it stopped totally, and took every darn intervention in the book to get it back! And if you go to the hospital and your waters have ruptured at all, you're not going home. Thank God I had a midwife who wasn't going to send me for the C-section if it wasn't absolutely necessary. Most places won't let you go more than 24 hours after your waters rupture before doing a c-section, mine let me go 53.5, which was long enough to deliver normally.