Some antibiotics can cause birth defects...you should check with a pharmacist and make sure that it is safe to ttc. I was on antibiotics a couple months ago and our doctor knew we were actively trying so he made sure to tell us to make sure not to get prego while i was taking them. Good luck!
I've heard about Mucinex and Robitussin helping with the cervical mucus (thickening it up) during ovulation. But my concern would be taking the anti-biotics into being pregnant. You might want to wait until the anti-biotics are out of your system, just in case.