flea and tick medications during pregnancy

My long-haired chihuahua is pregnant. I was wondering if Frontline is okay to give to her while she is pregnant? If not, what is? This is her first litter and my first experience as well. Thanks! :usa:

As she is pregnant, it would be a good idea to visit the vet and at that time you can ask him/her if anything at all should be used. :)