Does your blood type – specifically, your Rh factor (positive or negative) – matter in your daily life? Not in the slightest. But when pregnant your Rh status can matter, especially if it's negative.

Add Yahoo as a preferred source to see more of our stories on Google. Early in your pregnancy, you'll take a blood test to determine whether you are Rh-positive or Rh-negative. Rh, or rhesus, is a ...