Is ITP hereditary?

I developed antibodies when pregnant with each of my children over 40 years ago. My question is can this trait be passed on to my offspring or grandchildren?

Generally speaking, no. There are hereditary types of ITP but if that were the case, it would probably have shown up by now in your family members.
Autoimmune disorders are hereditary though, so family members can be predisposed to acquire them if one family member has one. I don't know much about Gestational ITP and if you only had problems while pregnant, it might not even considered an autoimmune disorder.
I didn't realize that they were able to test for antibodies that long ago.

It was very unusual 40 years ago. I fascinated all of the Dr's in Boston and had to be sent out of state for blood tests.

I developed antibodies that killed off two of my babies platelets at birth, I have negative platelets, my husband has positive. My third child was not affected as he probably inherited my negative platelets. His wife is now pregnant with their first child. This baby is the one I am concerned with. If this baby inherited the - platelets could this child develop antibodies in utero that could harm the mother?

My other two children inherited my husbands + platelets so they had no issues with their babies.

I have read on this site that there is a possibility that if I was to get a blood transfusion I could have a reaction that could harm my own platelets.

My mother had Lupus. Hope you are doing well.

Jen, platelets are not positive or negative. Blood types are though and if a mother is RH- and the baby is RH+, that can cause antibody production that can harm the baby. This doesn't have anything to do with ITP. Doctors are usually on top of this these days and can treat it before it becomes a problem.

My husband and I are both O positive, there are other blood factors and it is completely normal to have positive or negative platelets. We had blood tests for this which showed my platelets being negative and I developed antibodies which killed off my babies platelets at birth.

jeannek wrote: My husband and I are both O positive, there are other blood factors and it is completely normal to have positive or negative platelets. We had blood tests for this which showed my platelets being negative and I developed antibodies which killed off my babies platelets at birth.

Hi Jeanne. I can relate my experiences with having three babies while having ITP myself. Because of the ITP itself, I have antibodies in my blood that cause my body to incorrectly mark my own platelets as foreign bodies for destruction. During all of my pregnancies, these antibodies crossed the placenta and caused my children to be born with low platelet counts. Because they don't actually have ITP like I do, they just had to follow up with a pediatric hematologist for approximately the first 3-4 weeks of life for platelet counts. Their platelet counts had all returned to normal levels, in all three children, by about 1 month post-partum. That is about how long it took their systems to work through the antibodies that they had received from me during the pregnancy. They are all quite healthy now (15, 12, and 10) and have no platelet issues whatsoever. (And just as a note, I am RH+ and all of my children are RH+, but again, this just affects red blood cells, and platelets aren't positive or negative that I am aware of.)

Regarding positive and negative blood types, those markers are on red blood cells, not platelets as far as I understand. Mothers who are RH- who carry babies who are RH+ may pass antibodies across the placenta (particularly in second pregnancies and beyond) that destroy red blood cells in the baby. This can lead to severe jaundice and other complications, but nowadays they are easily able to test for this case in mothers who are RH- and can treat with RhoGAM.

Anyway, maternal ITP can definitely affect newborns. If the family member you are talking about doesn't have ITP herself and is not RH- then there should be no issue. Even a mother with ITP (like me!) often can have perfectly safe deliveries.

A person can develop antibodies to platelets, but platelets are not positive or negative.