I'm 33 weeks pregnant with just two small cavities in my two back molars, is it better to wait till the baby is born to fill them?

Cavities: Any dental treatment should be avoid until the las trimester. If thr cavities are small you can wait but please please make sure to exercise a good oral hygiene.

Talk to your dentist: Dental work can safely be done during pregnancy. During the third trimester you may may be too uncomfortable to have the fillings done. Talk to your dentist about the cavities to see if you can wait a few weeks until after you deliver. For small cavities it should be ok to, wait. But if you have pain or signs of infection you cannot wait.

Are you sure?: I am assuming that you did not have x-rays taken in the last six months. If that is the case, you really can't be sure that those cavities are small nor that you don't have other dental problems that could not be seen without x-rays. Although you should discuss this with you own dentist who has actually examined you, i would probably wait until after you deliver & the get x-rays\all treatment done.