Is there a paternity test that can be performed prenatally?

Yes. There is a non-invasive paternity blood test that analyizes fetal dna circulating in the mother’s blood. The baby’s dna is then compared to the dna taken (by buccal swab) from the potential father. This test can be performed as early as 10 weeks into the pregnancy. I highly recommend labtest md for testing. They have several locations.
PRENATAL PATERNITY T. Yes it can be done in the second trimester from 14 to 20 weeks gestation.Under ultrasond guidance a needle is placed in the uterus to draw out amniotic fluid and which is tested against the dna of the prospective father or fathers to establish paternity there are some risks involved of losing the baby and other complications.