Vaccinating Pregnant Dogs or Cats – Don't Do It!

Last updated: February 07, 2022 by Marty Greer, Doctor of Veterinary Medicine

When working with pregnant dogs, queens or females that we are trying to get pregnant, it is all about getting the mom as healthy as possible because she is the incubator for the embryo.

What Happens If You Vaccinate a Pregnant Dog or Cat

When a mom is pregnant and especially during the first half of pregnancy, inflammation of any kind has been shown to decrease the number of embryos carried to term. Inflammation can prevent implantation or disrupt the placenta, causing embryo death or failure. Days 18 to 25 are most important but inflammation at any time during the first 30 days can cause trouble.

Vaccinating a mom during pregnancy has little medical advantage, as it is unlikely to help the litter she is carrying. Breeders often want to vaccinate to help colostrum antibodies. However, this does not work, as it takes 30 to 45 days to get antibodies high enough in the blood to impact colostral antibodies in the milk.

If we don't want to vaccinate during the first half of pregnancy for fear of embryo loss and vaccinating during the last half does not give protection to this litter, that leaves no good reason to vaccinate pregnant moms except convenience, and that is too risky for the embryos!

When to Vaccinate

Maiden females (first-time moms) are often vaccinated before they become pregnant, when they start into their first breeding heat. We have 10 to 14 days until mom ovulates and another 18 days until the embryo is implanted. These 30 days are enough to get past any vaccine inflammation. The risk of embryo loss and inflammation is minimal.

We only vaccinate if mom is in need of vaccination. For first-time moms, we usually vaccinate for protection against Lepto abortion. The preferred time to vaccinate is after the female is one year old. If we do this, we are ready for the next heat cycle and do not have to vaccinate mom at a critical time.

A lot happens in a dog mom in 64 days of pregnancy. Adding vaccinations to mom's to-do list makes little medical sense. It is all about the baby, so we don't want to give anything to mom that will endanger the embryo she is carrying.

If you need help, call us at 800.786.4751.

-Dr. Bramlage
Donald Bramlage, Doctor of Veterinary Medicine, Former Director of Veterinary Services at Revival Animal Health

Donald Bramlage, Doctor of Veterinary Medicine, practiced veterinary medicine for 30+ years and is known for his work in managing parvovirus. He received his Doctor of Veterinary Medicine from Kansas State University in 1985. He served as Revival's Director of Veterinary Services from 2011 until his retirement in 2019.

When your dog or cat isn't pregnant, use the Revival Vaccine Finder to help choose the right vaccines for your pet.