Thanks for the answer...I too am A- and was wondering the same thing. Is the first shot only given at 27-28 weeks, or does anything have to be done earlier? (I'll ask my doctor on the 30th, but was just curious.)
__________________ Married DH June, 2007
DD born April, 2009
Miscarriage April, 2011
At my last appointment a couple weeks ago, I asked about it as nothing had been said. I found out I am B-. They told me it was just simply a shot at 28 weeks and then depending on the baby's blood type it might be followed with a second. There is a protein in some blood that makes the blood type positive if its there and negative if it's not. The protein can be very dangerous if it enters the bloodstream of a negative person, thus the rhogam shot. It has an effect on the protein but does nothing else if it's not there. I would say the best way to tell if you'll need the follow up shot is if you know your partner's blood type. If he is positive then the baby will be positive and then you'll need the follow up shot. If he's also negative, then the baby will be negative and no need for more than the one shot.
As I said I will be getting my shot at 28 weeks, I can't say for sure if that's a routine time, or just what works at our office.
I'm not sure if I'm talking about the same shot or not, but when I had my m/c (this was my second pregnancy), they told me that if my blood type was negative (I didn't know it at the time), then the m/c could've been due to that fact. As it turns out, I'm O+, so that wasn't the case. But the doctor told me that it doesn't affect first time pregnancies usually (and maybe, thus the reason they wait to give the shot until 28 weeks), but it can affect pregnancies after the 1st, so if you have a negative type blood, you should have the shot as soon as you find out you're pregnant, just to be on the safe side.
But definitely talk to your doctor to be sure.
Married my best friend - July 06'
Mommy to Liam Carter - May 07'
Lost our little angel - m/c January 08'
Our newest bundle, Brody Anderson! - February 09'