Blood tests and ultrasound don't affect the growing baby. Amniocentesis and CVS carry a very small risk of miscarriage or needle injury to the baby. Are there prenatal tests for Down syndrome?

How the Rh Factor Test Is Done. The Rh factor test is a simple blood test. It won’t harm you or your baby. The doctor will use a needle to take a small amount of blood from your arm.

Testing pregnant people's blood to look at free-floating DNA can tell doctors about the health of the fetus. But these tests sometime turn up DNA that might be shed by cancerous cells.

The blood tests of the future can reveal a lot more about a person's health, from neurodegenerative conditions to age-related diseases, said the Hong Kong clinical pathologist whose pioneering ...