Making sure your dog is flea and tick free during pregnancy is essential. Fleas and ticks can be very dangerous for a pregnant dog, because her hormones and immune system are already at risk. Additionally, a pregnant dog with fleas or ticks can put the newborns at risk. This is because fleas and ticks can pass from the mother to the newborn while it is still in the womb. This is extremely dangerous for a newborn, as any health defect in the early days of a newborn’s life can be deadly.

Can pregnant dogs have flea and tick medicine?

Pregnant dogs can take most flea and tick medicine without an issue. For example, the most common flea and tick medicine for dogs (Seresto dog collar and Frontline) have both been tested and proven to be safe for pregnant dogs. Both these flea and tick medicines have licenses to be sold and used on pregnant dogs.
However, there are some popular flea and tick medicines that have not been proven safe for pregnant dogs. This is the case for the popular flea and tick medicine Nexgard. On the Nexgard manufacturer website, it says that using Nexgard on pregnant dogs has “not been evaluated.” There is also another popular flea and tick medicine (Simparica) that has not been evaluated and tested on pregnant dogs. For that reason, we strongly recommend choosing a different flea and tick medicine if your dog is pregnant.
For a safe rule of thumb, only give flea and tick medicine to your pregnant dog if it says on the bottle that the medicine has been tested and approved for pregnant dogs.

How old do dogs have to be to take flea and tick medicine?

While there are some flea and tick medicines that are safe for pregnant dogs, just about all of them are not safe for newborn puppies. Some flea and tick medicine is safe for puppies that are 6 weeks old, while others are not safe until the puppy is 6 months old. It is very important that you always read the label on the medicine to review the safety precautions for a medicine before you give it to your dog. We also strongly recommend consulting your vet before giving flea and tick medicine to your dog, even if it is over the counter medicine that doesn’t require a prescription.