Help with blood types

[Kae]

Can two negatives make a positive?

[GraceAmazing]

Not sure about that, but are you worried about the Rh factor?

[Rachel]

What exactly are you wondering about blood types?

[Kae]

Originally Posted by Rachel

What exactly are you wondering about blood types?

I am O- and my husband is A-. Can this combination make a A+ baby?
With my first two children we were in the military and they would give you the rhogram if you were negative no matter what your husbands blood type was. The reason for this is because they didn't know who the father was and assumed you didn't either. I have had a midwife with the rest and didn't worry about it. I was told that two negatives can't make a positive. With my 7th child I ended up with a c-section in the hospital and they told me I needed the rhogram because the baby was A+. I questioned a little and they said two negatives could make a positive. I was drugged and out of it and my husband was driving in from out of town. I forgot about and it hasn't been a concern until this pregnancy. They are saying that it isn't possible to make a positive with two negatives. Just looking to see if anybody has more knowledge on this. The doctor's have been taught that it isn't possible and make it sound like it isn't something they are not really sure on.

[GraceAmazing]

I am negative and so is my husband and we have two beautiful girls. One has positive blood and the newest one is negative. So that being said, I received rhogam for both pregnancies...including during and after. Why couldn't you just ask for the shot to be on the safe side??? The rhogam is also for the next pregnancy. That's what my OB/GYN explained to me.

[rgcraig]

I found this online:

http://www.drgreene.com/21_1003.html

There is a chart there that shows possible blood types and impossible blood types of the children.

[HeavenlyOne]

For those of you with positive children who's parents are both negative, I suggest you get another blood test.

Most individuals have two blood type markers on their cells. Of the ABO blood types, you have a dominant gene and a recessive gene. It's the same with the Rh factor. In positive people, they could have a negative recessive gene and if they have a baby with someone who is positive and negative, the baby could be negative even though both parents are positive. Follow?

Mom is +- and dad is +-. This means there is a 25% chance they will have a baby with -- markers.

It's impossible for it to be the other way around because to be negative, you have to have both genetic markers negative, one from each parent you have. Since positive markers always dominate negative markers, if you are negative, you have only negative markers.

If mom is -- and dad is --, there is only one possibility in all children.

Therefore, if both parents are Rh negative then the children will be Rh negative.

I did find this little tidbit while looking around, however.

Some individuals have red blood cells which are Del, meaning they have a very low level of D antigen (the molecule on the surface of red blood cells that makes them Rh-positive) which is generally not detectable by Rh factor testing, but can induce anti-D antibodies in a true Rh-negative individual. If the baby's father was Del, he would type as Rh-negative but in fact be Rh-positive (with much much lower levels of the antigen than most Rh-positive individuals), and the baby could also be Del which would potentially still result in the usual complications with an Rh- mother carrying an Rh+ child.

However, this doesn't make a positive blood type because, just as in the father, the Rh positive markers would be undetectable.

[HeavenlyOne]

References:

http://ask.metafilter.com/76686/An-O...gative-parents

http://www.drgreene.com/21_59.html

http://se.babycenter.com/pregnancy/c...onbloodexpert/

That last site has a lot of good info.

[Pragmatist]

There is a lot that science doesn't know yet, so I would never say never. I just recently learned that two people with O could produce an A baby, the A antigen is recessive.

[Kae]

Thanks for the help. Those links answered my question. I am actually going to get the baby retested this afternoon. If he is still positive then we will have to get my husband tested. My husband was in the military and they are the ones that labeled him A-. I have a hard time believing they made a mistake. He was in for too many years for them not to have caught it.