Before: Dogs are pregnant on average for 63 days. Thirty days into pregnancy take her to veterinarian for a checkup. Unless instructed to by your vet do not give medications unsafe for pregnancy or vaccines. Size of litter is important therefore 45 days into pregnancy take your dog in for X-rays. One or two puppies could pose a problem. Smaller litters tend to have puppies of greater size. Puppies of a larger size require a C-section. Pregnant dogs should eat puppy food because it contains more calories. The mother will need to pass nutrients onto the fetuses. Prepare a nesting area about a week before your dog is due to begin labor. Set up the nesting box in a quiet, private area. Place blankets and towels in the area to make it comfortable.
During: There are many signs to when labor is near. The teats will appear enlarged because her milk is coming in. This typically happens a few days before or as labor begins. Start taking your dog’s temperature two to three times a day at the same time. About 24-48 hours before your dog goes into labor, their temperature will drop from 101.5 F (which is normal) to 98-100 F. Once temperature drops bring your dog to the nesting spot. If you see green discharge this means contractions have begun and they will appear as a wave across her belly. When dogs go into labor instincts take over. For the most part you are just there for your dog. Puppies can be born head or tail first; both are normal. Delivery process can take anywhere between an hour to 24 hours. If labor lasts for four hours with no puppies or between puppies call your veterinarian. Traditionally, a pup is born within 45 to 60 minutes. Puppies are born in a sac. The mother will open the sac and tear the umbilical cord herself. If she does not you should gently open the sac and clean off the puppy. Stillbirths are common for most littered mammals. If you see a puppy not breathing try to clear the mouth and rub the body to stimulate the puppy.
After: After birth continue feeding your dog high calorie food. She is still nursing her puppies and is in need of the extra calories. Without proper nutrition she cannot recover properly and it helps the puppies develop. Dogs are susceptible to certain illnesses after giving birth, metritus (inflammation or uterus), eclampsia, and mastitis (inflammation of breasts). If you dog displays any unusual behavior contact your veterinarian.
More info on food for pregnant dogs: http://www.hillspet.com/dog-care/feeding-pregnant-nursing-dogs.html