Department of Obstetrics and Gynecology, Rabin Medical Center, Petah-Tiqva 49100, Israel
Dear Sir,
We read with interest the letter by Hillensjö et al. and agree with the authors that individualized combined strategies should be applied to prevent ovarian hyperstimulation syndrome (OHSS). However, we have some comments regarding their experience and conclusions.
Hillensjö et al. report a 12% incidence of severe early or late OHSS in their clinic despite the routine use of prophylactic albumin and individualized combined strategies. This rate is compatible with the accepted incidence of severe OHSS in the general in-vitro fertilization (IVF) population (Medical Research International, 1992).
The analysis of all the prospective studies of this issue, as already reported (Weissman et al., 1999), yielded a beneficial role for prophylactic albumin. However, these studies include 78 and 74 patients in the albumin and control groups respectively. A careful reading of our opinion (Orvieto and Ben-Rafael, 1998
) shows that these numbers are very small, because `the required sample size to allow the detection of 50% reduction in the 20% incidence of severe OHSS, with type 1 error of 0.05 and 80% power, revealed that 387 patients are needed in each study group'.
Furthermore, if our paper is indeed read `critically', it becomes clear that there is actually no contradiction between our opinion and that of Hillensjö et al. We concluded that the literature found no role for albumin in the prevention of late OHSS, while its role in the prevention of early severe OHSS is still debatable. Until an adequate prospective study designed is available, the statement that `the evidence presented in our review strongly suggests that albumin should be used to prevent severe OHSS' may be considered both non-scientific and dangerous.
References
Medical Research International/Society for assisted Reproductive Technology (SART)/The American Fertility Society (1992) In vitro fertilizationembryo transfer (IVFET) in the United States: 1990 results from the IVFET Registry. Fertil. Steril., 57, 1524.[ISI][Medline]
Orvieto, R. and Ben-Rafael, Z. (1998) Role of intravenous albumin in the prevention of severe ovarian hyperstimulation syndrome. Hum. Reprod., 13, 33063309.
Weissman, A., Barash, A. and Shoam, Z. (1999) The use of intravenous albumin for prevention of severe ovarian hyperstimulation syndrome. In Shoam, Z., Howles, C.M. and Jacobs, H.S. (eds), Female Infertility TherapyCurrent Practice. Martin Dunitz Ltd., London, UK, pp. 309316.