I am A- and just had to have an anti-d shot after my twins were born and after my m/c. No biggie- just a shot in the bum. It was good that i did as one of my twins is A- and the other is A+ ( my DH is A+).

just gotta let your OB know. When the do the blood tests at around 10 weeks for the downs test, they will check your blood group and send you out a card with your blood type info. Even easier !
Odette