Ladies, it is very important that you know your blood type! So if you don't. I highly recommend that you find out, especially if you are TTC! If not, you may want to conceive later in life. Know your blood. If you are negative, your blood could attack your baby (if baby's blood is positive) & cause birth defects. Or miscarriage. There is a shot to make your baby's invisible to your blood cells.  Correct me if I am wrong but this was my understanding!