Can i do a dna test before my baby is born in december? could it hurt my baby or possibly cause a miscarriage? i am 18+6 weeks

Yes: If it is done by a competent physician under ultrasound guide a miscarriage is very unlikely although it could happen in rare instances.Therefore one needs to think about the benifit of the information versus risk

What would you test?: DNA test is a very broad category. Some can be done on the fetal DNA present in maternal blood, others require sampling of amniotic fluid or chorionic villi both of the later are invasive and carry a risk of miscarriage. This issue is too complex for this forum and you should talk to your OB.

Yes, but risky: Amniocentesis is a procedure performed during certain stages of pregnancy when risk factors for genetic defects are present. In the hands of a qualified physician, it is a safe and commonly performed procedure. It is NOT however without risk, as no procedure is ever risk free! Is the risk worth the benefit of having the information you are looking for?