The definition of 'poor response': Bologna criteria.

is believed to occur during the early stages of gamete fusion, and thus before the sperm tail is incorporated into the oocyte. Thus, our figure represents a specific temporal stage of fertilization and not the entire sequence of events. It would, therefore, be inaccurate and misleading to have shown the sperm tail incorporated into the oocyte at this stage. While we are content with the fact that Fig. 2 (Kashir et al., 2010) was indeed a correct representation of a specific temporal stage of fertilization, and we agree with Ramalho-Santos that specific attention is required in future publications with regard to the precise positioning of the sperm tail, we recommend that authors also need to place significant consideration upon temporal aspects of the specific physiological and molecular events being described in order to minimize the risk of reader misinterpretation. References Berridge MJ. Inositol trisphosphate and calcium signalling mechanisms. Fertilization: a sperm's journey to and interaction with the oocyte. Most fertilizing mouse spermatozoa begin their acrosome reaction before contact with the zona pellucida during in vitro fertilization. Oocyte activation, phospholipase C zeta and human infertility. Sir, We read with interest the article entitled " ESHRE consensus on the definition of 'poor response' to ovarian stimulation for in vitro fertilization: the Bologna criteria " published in the July 2011 issue of Human Reproduction (Ferraretti et al., 2011). In the Abstract section, the authors state that 'the definition presented here represents the first Figure 2 Schematic representation of the signaling cascade induced by PLCz following delivery into the oocyte as understood when Kashir et al. (2010) was published. Here, the sperm tail is not shown to be fused with the oocyte since the authors were referring to a specific temporal stage of fertilization and not the entire sequence of events. Reproduced from Berridge (2009) with permission.