reproductive technologies) textbook referenced above,[18] the risk of OHSS varies with the clinic administering the hormones, from 6.6 to 8.4% of cycles, half of them "severe." The most severe form of OHSS is life threatening. Recent studies have found that donors were at less risk of OHSS when the final maturation of oocytes was induced by GnRH agonist than with recombinant hCG. Both hormones were comparable in the number of mature oocytes produced and fertilization rates.[19][20] A larger study in the Netherlands found 10 documented cases of deaths from IVF, with a rate of 1:10,000. "All of these patients were treated with GnRH agonists and none of these cases have been published in the scientific literature." Hormone treatments that can be dangerous in the short-term may have long-term health effects. The long-term impact of egg donation on donors has not been well studied, but apparently some evidence suggests an increased risk of ovarian cancer, and effects on fertility.[18][21] 1 in 5 women report psychological effects from donating their eggs, both good and bad. However two-thirds women were happy with the decision to donate their eggs. The same study found that 20% of women didn’t recall being aware of any physical risks.[15] This does not mean they were told the risks involved but were not concerned about them at the time. ]