My lab only had one puppy, its been over an hour since she gave birth.. what do I do now? Is she going to have more? How do I know? This is her first liter, does that matter.. if anyone can help me I would much appreciate it, thank you

What is she doing right now? How is she behaving?

My pit bull only had one pup. My ex father in laws dog only had one pup. I have known other dogs that only had one pup. It can take hours for the next pup, especially being her first litter.
Like Wondergirl asked how is she behaving?

my lab only had one puppy, its been over an hour since she gave birth.. what do I do now? Is she going to have more? How do I know? This is her first liter, does that matter.. if anyone can help me I would much appreciate it, thank you

How many pups did the vet see on ultrasound? Although the ultrasound can be wrong sometimes, it should give you a good idea of how many pups she should be delivering.

It can take a while between pups, so an hour isn't really that long. The fear is that a pup is stuck, which does happen more often than you think. If you're concerned it's always best to call your vet. He should be checking the mom and the pup anyway.

This is a good example why you x-ray your dog at 43 days. At that time, you can see the skeletons of the puppies and can get a good idea of how many you are expecting.

Although it is not normal for a large breed dog to have just one puppy, it is also not abnormal for them to have just one puppy. Things that cause this... It could be her first litter and/or heat cycle.. age.. fertility... fertility of the male.

You should really be asking your vet this question. Dogs that have puppies stuck inside them become sick quickly, not to mention the lives of the possible unborn pups is at risk after she starts labor.