[Valathreon]

So my near-death experience began before I was even born. My father had positive blood, while my mother's was negative. This causes children to have positive blood. My sister was the first child of my family, and her birth went off without a hitch. My brother had a platelet deficiency, which was resolved before it could do real harm. I, however, was the unlucky third child.

A few months before I was due to be born, my blood ended up mixing with my mother's. With my blood being positive and hers negative, her immune system had a bad reaction, and developed antibodies to try and destroy the "invader", or my red blood cells. This afflicted me with Rh disease. Eventually, I had to be cut out via Cesearean-section two months early in rather bad shape. I reckon if I had spent much longer inside the womb, I probably would have suffered hydrops fetalis, or fetal heart failure.

TL;DR My blood was incompatible with my mother's, her immune system tries to kill me in the womb.