All will cause severe congenital abnormalities. In general, all drugs should be avoided for pregnant bitches, including vaccines unless they are absolutely necessary for the maintenance of the bitch's well-being. And, in my estimation, there are very, very few circumstances in which they would be even considered. The last category we should talk about if we are going to talk about a healthy pregnancy, is diet. For the pregnant bitch the maintenance of proper body conditioning and muscle tone is important for the six to nine months before the anticipated pregnancy.
Overweight bitches have lower conception rates and have higher incidence of whelping difficulties.
Supplementation with vitamins and minerals is important for the bitch, particularly in the last half of pregnancy. The composition of diet is very important. The carbohydrate needs, of course, increase too but only in a small way compared to the protein needs. Fatty acids are important in the latter half of pregnancy and a fatty acid supplement such a primrose oil has been very helpful. Raspberry tea leaves that contain large doses of trace minerals have been very helpful in maintaining uterine muscle contractility control during whelping.