You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Rh incompatibility does not produce serious complications in the first pregnancy. Which of the following explains this phenomenon? and explain in detail?
Fetomaternal hemorrhage occur only at the time of delivery. Only in 5% cases transplacental transfer of RBC occur in the first trimester. The leak is very small and insufficient to produce primary immune response. Moreover as a primary response IgM antibodies are produced, which due to its large size do not cross the placenta. Therfore primary sensitization occur in less than 1% of first Rh incompatible pregnancy. Ref: Pregnancy at Risk: Current Concepts By Krishna, 4th Edition, Page 387 ; Textbook of Obstetrics By D.C.Dutta, 6th Edition, Pages 333-4