If you never went to the drs after a miscarriage could you get an infection or an sti?

Yes: Most of the time everything will be fine however. I would venture to guess that most miscarriages end without a doctor's visit. However sometimes the miscarriage is incomplete and some tissue remains inside. This can lead to a serious infection. Miscarriages in and of themselves don't cause stis, but it's certainly possible to have one that is not diagnosed if you don't go to the doctor.