Delivery of normal babies from embryos originating from oocytes showing the presence of smooth endoplasmic reticulum aggregates

Sir, The recent publication by Mateizel et al. (2013) published in Human Reproduction stimulated our interest. Since the above-mentioned paper is by far the largest study dealing with oocytes showing a dysmorphism called ‘aggregation of the smooth endoplasmic reticulum (SER)’, the results presented are of utmost relevance for both clinical embryologists and clinicians. However, considering the large dataset available the authors missed a good opportunity to shed some light on the possible negative influence of controlled ovarian hyperstimulation details on oocyte quality, in particular, the appearance of clusters of SER (Otsuki et al., 2004; Ebner et al., 2006, 2008; Sá et al., 2011). Most notably, the existence of natural cycles in the present study (Mateizel et al., 2013) would have allowed elucidation of any potential difference in ooplasmic appearance between those oocytes grown in conditions similar to the in vivo situation and their stimulated counterparts. Furthermore, vague correlations between organelle clustering and the type of stimulation protocol (Otsuki et al., 2004; Ebner et al., 2006) theoretically could have reached a level of significance due to the formidable number of patients and gametes. This brings one to the unresolved mystery of whether a change in stimulation or drug regimen would reduce the occurrence of the said intracytoplasmic anomaly since its repetitive nature has been documented (Meriano et al., 2001; Akarsu et al., 2009) with a recurrence risk ranging between 36% (Sá et al., 2011) and 39% (Ebner et al., 2006).