In-home, quick, inexpensive test kit to screen for a number of dog and cat health problems.  Alert your vet if you discover any abnormalities!
 

Additionally, past 65 days of gestation there is a greater chance for the placenta to separate from the uterine wall.  When placental separation occurs the delicate interface between the mother's blood and the pup's blood is compromised.  This is where exchanges of nutrients and waste products such as carbon dioxide are made so any interference with placental-uterine communication quickly leads to the demise of the fetus.