hi my dear of course it can not be .but if you if you do correct test. be cause some times if you do it in correct your type and Rh it can happen .pleas write the blood group of the mother and father for me .and tell from where you tell they are monozygot twins .and write for me the blood types of newborns .did you know about H substance or pseudo B

is there any infection with bacteria espacially psedomonas .or other nasocomial infection . please write the result of cell type and back .and the direct coombs test

resulte.

I am not aware of reports of monozygotic twins without identical blood types. Monozygotic twins are identical twins and have therefore the same blood type. THe only exception I could imagine is in case of postzygotic mutation. in this case identical twins can develop non-identical characteristics. Importantly, the majority (75%)of monozygotic twins are also monochorionic. Simce almost all monochochorionic placentas have vascular anastomoses allowing inter-fetal blood transfusion, this could (in the exceptional case of different blood types) then lead to blood chimerism.

And there are rare cases of dizygotic twin gestations undergoing post-zygotic fusion to result in monochorionic pregnancies (ie, appear to be monozygotic but really be dizygotic).

In fact, if very rarely might be in monozygotic twins different caryotype and even different  sex, why could not be different blood type? :) Look Enrico Lopriore answer

Depeng,

I think that something similar to what Marya G Zlatnik described took place during embryonic development of the monozygotic twins with different blood types.  Please refer to my blog about this phenomena for more details--see link below.  Personally, I find the likelihood of post-zygotic mutations to be very low.  Chimerism is a more likely explanation.  This would mean that the "monozygotic" twins are not actually from one fertilized egg, but two!

Nature is indeed complex and perplexing.

DeeAnn

http://www.deeannvisk.com/my-mother-the-chimera/

Normally monozygotic twins have same blood type except chimeric condition.

No

Monozygotic twins will have the same blood type, with a few very rare exceptions.

https://www.verywellfamily.com/how-to-tell-if-twins-are-identical-or-fraternal-2447140

For all practical purposes blood groups will be same