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Dr. Mattlee
Dr. Mattlee, Board Certified Physician
Category: Medical
Satisfied Customers: 5
Experience:  Own and operate a private medical practice, focusing on Mindful Internal Medicine.
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What would cause antibody m to show up in blood when both me

Resolved Question:

What would cause antibody m to show up in blood when both me and the father are positve blood types?
Submitted: 7 years ago.
Category: Medical
Expert:  Dr. Mattlee replied 7 years ago.
Do you know which class the antibody M belongs to, in particular IgM or IgG?

When you say you and the father are both positive blood types, do mean A pos, O pos, etc., or Rh pos?

For you to have antibody m show up in your blood only means you have been exposed to the antigen that stimulates that particular antibody m. Which could be bacteria, which have antigens on their surface that will stimulate production of antibody m, in particular the IgM type.

If you are RhD positive, then you will have anti-RhD IgG and/or IgM antibodies.

If you are RhD negative, but have had another child that was RhD positive, it is possible that during that delivery some of the babies blood got into your blood stream and you produced IgG antiRhD antibodies.

Does this make any sense? Or even begin to answer your question?
Customer: replied 7 years ago.
I do not know which class of antibody m it is. I am O+ and the father is B+ blood types. I have had another child and there were no antibodies that showed up, nor were there any Rh conflicts between the blood types. Also, my doctors had said that there were no signs of infection in my initial blood work. This is why everything I have read online is confusing. My doctor is also looking in to it, but I just did not want to wait 4 weeks until I find out the answer.
Expert:  Dr. Mattlee replied 7 years ago.
If the issue is Rh, then the first child could be the source, and you would not expect a reaction, because this would be your initial exposure that would lead to antibody production. So there would not have been a reaction with the first child, only subsequent children, since your body would produce the antibody secondary to exposure from the first child, though there would be no reaction.

Most Anti-M antibodies are the IgG type, which do not cause a problem in pregnancy. If it is the IgM type, they can cause problems similar to what happens with Rh incompatibility.

Unfortunately there is not way to tell without knowing more information about what type of Anti-M it is.

Also, in the initial question you said "show up in the blood", did you mean your blood? or did they do amniocentesis to check the babies environment?

The presence of specific Ig antibodies in your blood, would not necessarily be due to inheritance, as blood types are. So the father's status relative to the Ig antibodies is likely irrelevent.

Does this help answer your question? Or provide further clarification?
Customer: replied 7 years ago.

If Rh was not an issue in the first pregnancy then how would it cause a problem for the second pregnancy?


Yes I meant in my blood work, no amnio was done.


But I am still confuse about this. Is it something to worry about for my child and me or is it pretty harmless no matter which class of antibody m it is?

Expert:  Dr. Mattlee replied 7 years ago.
The reason Rh could be a factor in this pregnancy and not the first, is because in order to have the antibody in your blood there first has to be exposure. Once your body is exposed to a particular antigen (something from outside you body) you produce the antibody (made by your body), and only if the antigen is maintained will your body produce a reaction, and often there is a delay in producing the antibody (by several days). And if this is the case, then by the time your body produced the antibody to RhD with your previous child, the childs blood that came in contact with yours (i.e. the antigen) would be gone.

Therefore there would be no antigen for the antibody produced by you to react with. Until there is another exposure, which is the risk in subsequent pregnancies. Though this reaction is easily prevented by giving Rho-gam, which prevents your body from reacting to the antigen, if there is an exposure.

The class does matter for risk. If it is IgG class, little to no risk. If IgM some risk, unless it is Rh, which you would receive Rho-gam for, reducing it to little or no risk.

Though antibody-M complications during pregnancy are not very common. If there is a signifciant risk, they will monitor the blood levels of the antibody-M (the levels are called titers) through out your pregnacy.

Given there is treatment for Rh incompatibility, and the antibody-M compiclations are rare, I would not worry. The stress on the baby from worrying would likely cause more harm than any of the other issues.

You are doing the right thing by researching and asking questions, and the hardest part of being pregnant and having children is not knowing. This can be extremely stressful. Just remember, the chance of a reaction is small. For those that do occur or are present they are usually anticipated and/or predicted. And in the end, things just have a way of working out.

Each night when you lay down to go to sleep, visualize a smooth uncomplicated pregnancy, and the birth healthy, happy baby. This will have a greater impact than you can ever imagine. It is often our fears and stress about things that make them a reality. So relax, visualize the ideal, and believe it your heart.

Good luck to you, the father, and the new addition to your family.
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