Confirming whether or not your dog is pregnant requires a visit to your veterinarian, but there are some signs to look out for that may indicate that your dog is pregnant:
Early signs of pregnancy
Decreased appetite
Sudden decrease in activity
Nipple growth begins
Behavioral changes of wanting to be left alone or the opposite-- being overly affectionate
Late signs of pregnancy
Weight gain
Increased size of abdomen
Puppy movement can be felt
Milk production begins
Clear mucous vaginal discharge
Signs of whelping
Restlessness
Panting
Licking the vulva
Hiding
Some shivering
Vomiting occurs in some cases
Healthy dogs can deliver without assistance, however, you should educate yourself in case she experiences any complications and needs help.
Veterinary Confirmation
Your vet may use the following methods to confirm pregnancy:
Noninvasive ultrasound may detect a fetal heart beat around the 25th day from conception but is not considered reliable.
Blood tests to detect relaxin, a hormone present in pregnant dogs but not in non-pregnant dogs. This method may be performed mid-gestation.
X-rays which may not be done until late in gestation.
Pregnancy in all breeds lasts around 60 to 64 days.