Reply: Modified natural cycle IVF for poor responders
1 Unit for Human Reproduction, Aristotle University,Greece2 Center for Reproductive Medicine,Dutch Speaking Brussels Free University, Belgium
Email: stratis.kolibianakis{at}otenet.gr
Sir,
We would like to thank Dr Check for his interest regarding the study published by our group in Human Reproduction (Kolibianakis et al., 2004
).
Although it is quite clear that Dr Check strongly disagrees with the conclusion reached by our study, we could not identify in his letter arguments against the interpretation of the data presented. Apparently, Dr Check bases his strong disagreement on his own data (Check et al., 2004).
Several differences exist between the above two studies, some of them already mentioned by Dr Check in his letter. More importantly, however, the study by Kolibianakis et al. (2004) is a prospective evaluation of the modified natural cycle (MNC) for IVF in 32 poor responders with high FSH levels and previous unsuccessful IVF attempts. These patients, who were offered but did not accept oocyte donation, performed 78 MNC for IVF using recombinant FSH and GnRH antagonists. The study by Check et al. (2004) is a retrospective report of unstimulated or minimally stimulated cycles without the use of GnRH analogues. It is not clear from the study by Check et al. (2004) (or the letter of Dr Check) how many patients were treated in their study or how many previous IVF attempts the patients analysed had performed.
What is clear, however, from the study by Check et al. (2004), but not from Dr Check's letter, is that 12 deliveries were achieved after 259 IVF cycles. Thus the delivery rate per cycle is 4.6% (12/259), 95% CI 2.4–7.9. In the study by Kolibianakis et al. (2004) no pregnancies were achieved after 78 modified natural cycles for IVF and the corresponding statistic is 0.0% (0/78), 95% CI: 0.0–4.7. Therefore, it is not clear to us why Dr Check thinks that the two studies reflect differently the situation in the population and why the data by his group are more encouraging for this category of patients.
We also believe that the influence any study might have on the treating physician is not dependent on the journal in which it is published but is mainly based on its internal and external validity.
References
Check ML, Check JH, Wilson C, Choe JK and Krotec J (2004) Outcome of in vitro fertilization-embryo transfer according to age in poor responders with elevated baseline serum follicle stimulation hormone using minimal or no gonadotropin stimulation. Clin Exp Obstet Gynecol 31, 183–184.[Medline]
Kolibianakis E, Zikopoulos K, Camus M, Tounaye H, Van Steirteghem A and Devroey P (2004) Modified natural cycle for IVF does not offer a realistic chance of parenthood in poor responders with high day 3 FSH levels, as a last resort prior to oocyte donation. Hum Reprod 19, 2545–2549.
Submitted on March 22, 2005; accepted on April 5, 2005.
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