Answer: One of the first tests a pregnant woman should expect is a blood-type test. This test checks her blood type and Rh factor. Her Rh factor may play a role in her baby's health, so it's important to know this information early in pregnancy.
Explanation: if you're Rh negative and your baby is Rh positive, your body might produce proteins called Rh antibodies after exposure to the baby's red blood cells. The antibodies produced aren't a problem during the first pregnancy. The concern is with your next pregnancy.