* Author Topic: Blood Group possibilities for a baby from Mother's and Father's blood groups  (Read 12942 times)

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Offline bundles

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  • Time is an illusion, lunchtime doubly so ! D.Adams
Hi ladies. I am often asked about the relevance of blood group matching for donors, with a view to producing a baby that would be a possible blood group from the parents. Obviously this is mainly important if you are not intending to tell the child.
It is a simple matter of genetics, and after drafting out all of the possibilities I have actually found a really good representation on The Australian Red Cross website ! I have simplified a couple of things and included a table for Rhesus factor too (Rh+ve Rh-ve) which should be considered after you have looked at the ABO system.

For info: Very simply, in this case, Genotype means what the 2 genes actually are and Phenotype means what the blood group tests to be (or shows itself as)

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Inheritance patterns of blood groups

Blood groups are inherited from our parents in the same way as other genetic traits (eg, eye colour). ABO and Rhesus are the most well-known among the blood group systems.

ABO inheritance patterns
The ABO blood group system is determined by the ABO gene, which is found on chromosome 9. The four ABO blood groups, A, B, AB and O, arise from inheriting one or more of the alternative forms of this gene,  namely A, B or O.

Genetic Combinations of ABO Blood Groups

Blood group        Possible genes

       A                             AA or AO

       B                             BB or BO

      AB                                 AB

       O                                 OO

The A and B genes are co-dominant so both A and B antigens will be expressed on the red cells whenever either gene is present. O genes do not produce either A or B antigens, thus, are sometimes called ‘silent' or recessive genes.

 

ABO Inheritance Patterns

Parental blood groups   Child's blood group

       O and O                                   O

       O and A                                O or A

       O and B                                O or B

       O and AB                              A or B

       A and A                                 A or O

       A and B                         O or A or B or AB

       A and AB                           A or B or AB

       B and B                                O or B

       B and AB                           B or A or AB

     AB and AB                           A or B or AB

Note: These are various possible blood groups that children may inherit according to the combination of parental blood groups.

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Rhesus inheritance patterns

The Rh blood group system is attributable to two genes, RHD and RHCE, which are located on chromosome 1.

Rh positivity or Rh negativity is distinguished by testing for the RhD antigen, the expression of which depends upon whether an RHD gene has been inherited from one or both parents.

The RHD gene is dominant so a person is considered to be RhD positive whenever this gene is present, even though the gene may have been inherited from one parent. Conversely, a person will be RhD negative if no RHD gene is inherited.

 
  Parental Rh type                          Child's Rh type
Positive and Positive                    Positive or Negative

Positive and Negative                  Positive or Negative

Negative and Negative                        Negative

Note: These are the various possible Rh types that children may express according to the combination of parental Rh phenotypes.

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The original website is http://www.transfusion.com.au/?q=node/77


The easiest way to use the table is to look up yours & your partner's possible children, then the donor's and your partner's (if you are using DE) or the donor's and yours (if you are using DS).

For example. I am AB & my partner is O. Our possible children could be A or B. I was initially offered a B donor which could have produced B or O. Since I can't possibly produce an O child with my OH, I rejected her.

I appreciate this may be a little confusing for some & if you are really struggling, feel free to ask questions.  ^hugme^
Bundles xx

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    Offline Lilly83

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    This is amazing thanks so much for taking the time, it's very interesting

    I'm o neg and my donors b pos, I'm not sure what DP is will have to find out

    L xx

    Offline wibble-wobble

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    There was me thinking that because I'm A+ and so was the donor that my baby would be too. My dad was A+ not sure what mum is. I thought you got the blood group of one of your parents.

    If I've understood right my lo could be A or O + or -  :)

    Offline bundles

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    • Time is an illusion, lunchtime doubly so ! D.Adams
    Lol yes, although it depends on whether you were AO or AA yourself, likewise your donor. If you knew your mum's was O then you would def be AO. Probably your LO will be Rh+ve
    xx

    Offline CrazyHorse

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    Bundles, it's VERY rare, but an AB woman *can* have a phenotype O child. It's called the Bombay phenotype because it was originally discovered in Mumbai, and occurs when a person inherits A and/or B alleles, but is unable to produce the H antigen which is a necessary precursor to expressing A or B antigens. Wikipedia has a pretty good explanation of it: http://en.wikipedia.org/wiki/Hh_blood_group.

    My grandmother was told by her doctors that she was AB-, and my mother has always been typed as O+. (No question of donor eggs, obviously, or adoption.) I don't think my mother has been given any transfusions, so don't think she would ever have been checked for H antigen. I don't know whether my grandmother was misinformed and was actually A-, like my mother's sister, or if my mother is a rare H-deficient individual. My sister and I are both good old A+ courtesy of Dad.

    Not saying the Bombay phenotype thing should change your mind about whether to consider egg donors from additional blood groups, but thought you might like to know.  :)

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    Offline bundles

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    • Time is an illusion, lunchtime doubly so ! D.Adams
    CrazyH  :)
    Being a microbiologist/biochemist my training in Haematology was fairly limited so I was not aware of the Bombay phenotype. However, I've just spoken to a good friend who is a Chief in Haematology & he said whilst it is very rarely possible, in over 30yrs he's never seen one. And as Wiki says "This very rare phenotype is generally present in about 0.0004% (about 4 per million) of the human population, or 1 in a million people in Europe" so I guess it's uncommon enough not to really be a factor in donor choosing  ;D unless, of course, you are choosing a donor from India !

    He also said that he felt your grandmother was misinformed or remembers wrongly, particulary in light of sibling/offspring blood groups  :) but yes, it has made for an interesting read !!

    Offline solomum

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    just to point out that blood groups are probably a bit old hat by now.  My parents traced  relatives online by doing genealogical DNA searches.  I expect that DNA testing will soon be as common as blood testing once was.  so, if the OP is posting this, for the purposes of aiding those who wish not to tell, then it probably is not going to sufficiently close the door for a child finding out that they are not the biological offspring of their parents.

    Offline Lilly83

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    It's a very useful tool for us donor recipient ladies who often have to choose a donor by blood group, so it serves to assist us in our decisions

    Maybe in the future they may start matching donors by DNA but for now we get the blood group to go off

    L x

    Offline solomum

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    you can have a child with a donor of any blood group - certainly I didn't even look at blood group when I conceived.
     the only reason blood group becomes an issue if is you want the child to have a blood group that could be plausibly passed off as coming from both the parents (which I presume is why the OP is linking this to not telling).
    I know of two donor conceived children who found out this way that they were not the biological offspring of both their parents. 
    My point is that choosing the 'right' blood group is no longer sufficient to conceal biological differences if your aim is not to tell - as DNA testing is becoming so prevalent, and DNA analysis so much more mainstream, that offspring are likely to find out through this route that they are not genetically related to of one of their parents.

    Offline Lilly83

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    I know :) I agreed to take any, but some of us donor ladies like to match everything possible

    I think we should be mindful of not to do any 'scaremongering' and be supportive of those wishing not to tell, I'm sure they won't base their decision solely on this chart it's just something put together to assist

    I'm sure all ladies using donor conception are aware of the possibilitys of advances in testing in the future and I'm sure they will consider many factors when deciding

    L