If My Female Dog Gets Stuck With A Male While In Heat, Can We Prevent Her From Being Pregnant?

Chyene,

 The gold standard to prevent or end pregnancy is to have
your dog spayed.  This will take care of
current and future unwanted pregnancy. 
This is the safest method for your dog

 Abortive medications can also be given-- before any abortive
medication would be given pregnancy would need to be confirmed via ultrasound.

Lutalyse, a drug that is used to cause abortions after Day
30 of pregnancy, is available through your veterinarian. 

 Ann Falk, DVM

Take her to the vets as soon as you can and the date it happen .. The vets can give your dog 2 jabs .. Its like the morning after pill for us .. Its not 100% but they can tell you the odd hope this help you a little
Harleylou
Louise x

Yea. Get her fixed and get him fixed, unless your sole purpose is to breed which is stupid, there are enough unwanted dogs out there. ALWAYS spay and neuter all of your pets.

It is better to discuss this with veterinary doctor. The post coital medicines can work to avoid pregnancy in dogs, cats and horse. But remember every female either human or animals has rights to become mother.