Dogs will have diarrhea for a while after birth. If she is eating, drinking and caring for her puppies, most likely she is fine. I am going to give you a list of things to look for that would indicate a possible problem post delivery.
Here are some things you should look for. If your dog has intense abdominal pain, pale gums and tongue, sudden drop in temperature or collapse she needs to be seen as soon as possible as she may have uterine torsion.
If your dog has a Green, smelly discharge from her vulva, fever, loss of appetite and listlessness, it is possible she has a uterine infection due to bacteria or a retained placenta and needs to be seen immediately. It is likely she has metritis which is a uterine infection.
If your dog is experiences muscle weakness, muscle spasms, tremors or seizures, limb paralyses, she needs to be seen now as it is possible she has eclampsia. Calcium supplements, Tums, cottage cheese or goat’s milk may help, but it might not reverse the symptoms quickly enough.
Here is a site with more information on this.
Look for breast infections on a regular basis. If a breast becomes inflamed, red and hard to the touch, your dog will need to be seen by your vet.
Hope this helps and congratulations on your puppies.