Fruit of the Womb
Fruit of the Womb

Readers' Concerns Regarding Rh-immune Globulin and ABO-Incompatibilty

Anonymous said...
Great information! I just miscarried and I want to know why. I am 0- and received a Rhogam shot at 28 weeks with my 1st child. I did not receive a shot after delivery--I checked my records. Did this (not receiving a shot) contribute to my miscarriage? Wendy
Sun Sep 16, 12:10:00 AM 2007

Kenneth F. Trofatter, Jr., MD, PhD said...
To Wendy Sept 16: I am sorry for your recent loss. The most common cause of sporadic miscarriage in women who have had successful pregnancies is a fetal chromosomal abnormality. With regard to your other question, the routine would have been to give you Rhogam after you delivered UNLESS your baby happened to be Rh-negative as well. It is very unlikely that not getting the Rhogam after delivery caused you to miscarry your recent pregnancy. That doesn't even seem to be a problem with individuals who ARE clearly Rh-isoimmunized. It's dealing with those pregnancies after the first trimester that becomes the challenge! Regards, and thanks for your question.
Dr T

Sun Sep 17, Prefering Anonymity said...
My wife just delivered a baby girl 5 days ago who has elevated bilirubin levels with the cause thought to be ABO incompatibility. My wife is O-negative, I am A-positive and our daughter is A-positive/Combs-positive. My wife was not administered rhoGAM at any point during or after her pregnancy/delivery. Our pediatrician caught the jaundice fairly early and daughter is seems to be recovering, but I am also quite concerned with whether my wife and I can now safely have another child, as she did not receive rhoGAM. Is it possible for us to safely have another child and what would we need to do or screen for to do so? My thanks to you in advance

Kenneth F. Trofatter, Jr., MD, PhD said...
To preferring anonymity Sept 16: Your wife did not NEED Rhogam if your daughter was Rh-negative. ABO incompatibility is another issue. All people with O blood types make antibodies to A and B blood groups. They are exposed to those antigens in the environment (bacteria) and do not even need to be exposed to another human's blood to generate these antibodies. However, usually these antibodies are of the IgM class of antibodies. IgM antibodies are very large and basically contain a pentamer (5 antibodies) joined together. They are TOO BIG to cross the placenta to the baby. Occasionally, individuals also make anti-A or anti-B antibodies that are IgG class antibodies. These CAN cross the placenta and, indeed, IgG antibodies are a major source of 'immunity (passive immunity)' against common pathogens for the baby during the first 3-6 months of life.

Unfortunately, the placenta doesn't differentiate between 'good' (protective) IgG antibodies and antibodies that might harm the baby. This is the same problem with Rh-isoimmunization when it occurs. The antibodies from the mother cross the placenta, attach to the fetal tissues that are foreign (in your baby's case blood group A red blood cells) and that signals the baby's immune system to destroy whatever the antibodies are attached to - at that point the baby's immune system cannot distinguish what uis 'foreign' and what is 'self'! With the destruction of the baby's own red cells, hemoglobin is released and its breakdown product, bilirubin, can cause jaundice and more serious problems if the bilirubin levels get high enough. When the baby has used up all the antibody it has gotten from Mom, it will not have anymore problems.

To answer your other question, yes it is safe to have another baby under these circumstances. Often ABO incompatibility isn't much of a problem until after the baby is born, unlike with severe Rh-isoimmunization. Your doctors can assess the degree of fetal anemia in utero, indirectly, by doing peak systolic velocity of blood flow in the baby's middle cerebral artery by Doppler flow velocimetry if you are worried about fetal anemia during the pregnancy. Let them explain that to you! Best of luck, congratulations on your new baby, and thanks for reading and the great questions.
Dr T
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