"Hydrops, an abnormality common in cloning in which fluid builds-up in the fetus and/or placenta, can lead to abortion, stillbirths, or early deaths of clones, and usually results in euthanasia of surrogate cows. The incidence of hydrops in cloning is as high as 42%, but in natural breeding or other assisted technologies the condition is extremely rare, with estimates as low as 1 in 7500."