Do you call your ob if you think you should go in to l&d for maybe pre-term labor signs but you're…

Do you call your ob if you think you should go in to l&d for maybe pre-term labor signs but you're not home so it wouldn't be the normal hospital or do you just call the hospital you're going to? Will they be able to help or do I have to call my ob first? *also it's one am my time so I don't want to call my ob if I don't have to*