safest (and cheapest) option is to wait until babys born and do dna test...but obviously you have to get permission from the possible dads etc ..gd luck x
Amniocentesis has a risk of miscarriage if done early in pregnancy or rupture of membranes if done in third trimester.
I doubt if insurance will cover any paternity testing. Prenatal DNA testing can be over $1500 and that is if you can get either partner to consent to having their blood drawn. Other blood draw is from you.
If you know when you ovulate that could also help from what I learned once you ovulate and the eggs fertilised that's the deed done if you don't know then just go with the DNA, u had this dilemma at the beginning of pregnancy and had to check my dates and I know when i ovulated and such so my minds at ease good luck to you!
You can do a DNA before baby is born. Amniocentesis or a blood draw ..their are labs who do DNA but insurance won't cover it..it can cost excess of $1000.00.
You'll probably have to wait till after the baby is born to do a DNA test.