Breeding, Reproductive Health Advice, Vaccines

Vaccinating Pregnant Dogs or Cats: Don’t Do It!

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 dog or cat 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.

Why Should Pregnant Dogs Not Be Vaccinated?

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!

Can You Vaccinate A Dog Before Breeding?

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.

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

Article originally written by Donald Bramlage, DVM, Revival’s Former Director of Veterinary Services. This article has been updated/reviewed by Dr. Greer.

Written by: Marty Greer, DVM

Director of Veterinary Services

Marty Greer, Doctor of Veterinary Medicine, has 40+ years’ experience in veterinary medicine, with special interests in canine reproduction and pediatrics. She received her Doctor of Veterinary Medicine from Iowa State University in 1981. She’s served as Revival’s Director of Veterinary Services since 2019. In 2023, Dr. Greer was named the Westminster Kennel Club Veterinarian of the Year.

If you need help, call us at 800.786.4751.