At the same time, an article in the journal Thrombosis and Thrombolysis has warned of a possible increase in side effects of fertility drugs, including paralysis, limb amputation and death. Among all women undergoing fertility treatment -- or donating eggs for research -- about 10% will suffer milder forms of ovarian hyperstimulation syndrome (OHSS), while 1% will be at risk of life- threatening blood disorders. The authors of the study believe that the problem will become more common as the number of procedures rises. Doctors prescribing the drugs needed a better understanding of the potential risks, they said.