To the Editor
We would like to thank
Richter et al, 2017
for their interest in our study and their comments. It is indeed well recognized that the LH activity in urinary HCG is higher than that of recombinant LH, which helps to explain the generally better outcomes of stimulation among women with poor ovarian response when uHCG was used. As for the dose of FSH used, in the rLH group, patients receiving Pergoveris (Merck Serono) had 150 IU rLH and 300 IU rFSH via daily Pergoveris as well as additional rFSH 150 IU via daily Gonal F (Merck Serono). Therefore patients in the LH group received the same total daily dose of 450 IU rFSH as in the patients in uHCG group.We also appreciate the comment on the important point that the study was powered to detect a difference in the number of oocytes retrieved, but not pregnancy and live birth rate (LBR). This point was highlighted in the discussion section of our paper.
If LBR were to be the primary end-point of study, the sample size would need to be considerably larger and a decision made whether to include only the LBR from the fresh embryo transfer (ET) cycle or the cumulative LBR arising from all embryos derived from the stimulation cycle. There is no absolute right or wrong answer as there is inherent bias in each of these two approaches.
The survival rate of vitrified-warmed embryos in our unit is 91–95% and therefore the possible adverse effect of vitrification/warming on embryo quality is minimal. Whilst we agree that endometrial receptivity is different for fresh compared to frozen ET cycles because of the supraphysiological hormonal effect on the endometrium after ovarian stimulation, the cumulative LBR arising from all ET cycles (fresh plus frozen) helps to provide an overall picture of the total number of live births arising from the initiated treatment cycle.
Reference
- Letter to the Editor: LH versus HCG supplementation in poor ovarian responders.Reprod. Biomed. Online. 2017; 35: 433
Article info
Publication history
Published online: August 02, 2017
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© 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.
