You might find this article informative (go a bit down the page for how to cope with a bitch giving birth).
http://www.dogstuff.info/to_breed_or_not.html
this is an extract from it:
She�s in season and it�s time to take her to the veterinarian for a prenatal checkup and to make sure that her vaccinations, medications and worming are up to date. Once you�ve bred her, she should be under veterinarian care for any illnesses and should be kept away from any dogs that might pass viruses to her. Infestations, illnesses or diseases can affect the unborn puppies. Bitches can have miscarriages. If fetal death occurs early in the pregnancy, it is usually undetected and absorbed by the mother�s body. Abortion may result if fetal death occurs later in the pregnancy, and, dependent upon the cause of fetal death, the bitch may carry the remaining fetuses to term. A number of things can cause fetal death, including fetal congenital defects, the physical health of the mother, her uterus and placenta, malnutrition, anything that alters the health of the mother. This can include reproductive tract diseases and illnesses, such as cystic endometrial hyperplasia, adhesions (possibly from previous pregnancies or caesarian-sections), tumours or hormonal imbalances. Diseases known to cause fetal death include Canine Distemper Virus infection, Canine Herpes Virus infection, Toxoplasmosis, Campylobacter infection and Brucellosis (a type of Canine sexually transmitted disease).
You will still need to exercise your bitch. As the pregnancy progresses, your walks may get a bit slower. She will require about 30% more supplementary food during the last three to four weeks of her pregnancy. Now is a good time to put her on puppy food specially formulated for the needs of puppies and pregnant or lactating bitches. She may become a bit moody and