I am a lab tech and work in the blood bank of a pediatric hospital. I really can't think of a thing that you can do to prevent the problems with ABO incompatibility. The problem is that you, with type O blood, produce anti-A and anti-B antibodies. Unlike the Rh system, ABO antibodies are naturally occurring and can not be prevented. Your anti-B crosses the placenta and attaches to your baby's B antigens on its blood cells. It is not usually a problem because most ABO antibodies are IgM and are too big to pass through the placenta. We frequently have babies come in for us to test for ABO incompatibility and I have only rarely encountered a positive test. If your fetus with the next pregnancy was showing signs of distress, the treatment would be an intra-uterine exchange transfusion. Your baby would have his/her type B blood exchanged with type 0 blood. It is not guaranteed that your next baby will have type B blood. Your husband has two genes that code for blood type and B is dominant. It is possible that he has a B/O combination (you have O/O). Your first two may have gotten a B from him and an O from you, but if he is B/O, the next baby could get an O from him and an O from you and have an O blood type. If he is B/O then you have a 50% chance of having a type O baby next time. He could also be B/B, in which case there is a 100% chance that your next baby will be type B. There is no commonly available test to determine whether a type B person is B/B or B/O. I have not heard of ABO incompatibility ever causing the extreme situation you're talking about. The numbers I think you're referring to are bilirubin levels, and believe it or not, 15 is really not bad. My daughter's level was about 19 and she only had a few extra blood tests. We both have type O blood, but mine is Rh negative and hers is positive. Exchange transfusions on newborns are rare (we have maybe one a year) and the bilirubin would be upwards around 25. Are you positive that it is ABO incompatibility? There are a lot of other blood groups besides ABO and Rh, and it would be more likely that incompatibility is in one of these. I hope this has helped you at least a little. If you can think of any lab results (specifically, the result of the DAT or direct coomb's test of your last baby) that might help me, I could maybe help out a little more.
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