Intracytoplasmic sperm injection in dysmorphic human oocytes

Abstract

SummaryFertilisation and development of dysmorphic human oocytes recovered from hyperstimulated ovaries have been evaluated following intracytoplasmic sperm injection (ICSI) for treatment of male infertility. A total of 2968 oocytes at metaphase II of meiosis were injected, of which 806 (27.2%) were dysmorphic at the light microscopic level. Cytoplasmic abnormalities included granularity, areas of necrosis, organelle clustering, vacuoles, and accumulating saccules of smooth endoplasmic reticulum. Anomalies of the first polar body and zona pellucida, as well as non-spherical shapes of oocytes, were also noted. Contrary to previous findings linking some dysmorphisms to non-assisted fertilisation failure, in this study no single abnormality led to a reduction in the fertilisation rate, nor was fertilisation compromised in oocytes with multiple abnormalities. The incidence of normal fertilisation (two pronuclei and two polar bodies) was 69% in both the dysmorphic and non-dysmorphic oocytes. While overall pregnancy and implantation results were not altered in the group of patients (n = 242) in whom at least one dysmorphic oocyte was injected, exclusive replacement of embryos which originated from dysmorphic oocytes led to a higher incidence of early pregnancy loss. It is concluded that aberrations in the morphology of human oocytes – most probably a product of controlled ovarian stimulation – are of little or no consequence to fertilisation or early cleavage after ICSI. It is possible, however, that these embryos have a reduced potential for implantation and further development.

Developmental prognosis for zygotes based on pronuclear pattern: Usefulness of pronuclear scoring

“…In this work the author describes a similar frequency of aneuploidies in oocytes with granules in comparison with oocytes with normal appearance. For Alikani et al [27] the most commonly encountered cytoplasmic anomaly was partial intracellular necrosis, evidenced by the presence of several small scattered dense bodies (presumably chromatin) or pyknotic nuclei and the majority of such oocytes were normally fertilized.…”

An oocyte score for use in assisted reproduction

“…Many other parameters have also been analysed in oocytes such as zona pellucida thickness, spindle birefringence and extracellular dysmorphisms [36,47,48]. Results vary as to whether distinct oocyte dysmorphisms have any relation to fertilisation and development rates, probably due to a discordance in the scoring of these dysmorphisms [50], although an effect on pregnancies is often noted [21,36,47,50].…”

Policy of IVF centres towards oocytes affected by Smooth Endoplasmic Reticulum aggregates: a multicentre survey study

“…or extra-cytoplasmic dysmorphisms (increased peri-vitellin space, fragmented polar body, granular zona pellucida…) [2,3]. Since several years, it was suggested that oocyte morphology could influence success rates in assisted procreation [1,[4][5][6]. However, the variety of dysmorphisms and the studied consequences as well as the variety of experimental models and contradictory results did not allow drawing precise conclusions on the global impact of these dysmorphisms on pregnancy outcomes [7].…”

“…However, the variety of dysmorphisms and the studied consequences as well as the variety of experimental models and contradictory results did not allow drawing precise conclusions on the global impact of these dysmorphisms on pregnancy outcomes [7]. Moreover, most studies did not focus on the impact of an individual anomaly on IVF outcomes [1,[4][5][6]. SERa, on the other hand, have been studied independently by several groups and a negative effect of the SERa dysmorphism in terms of fertilization, embryo quality, implantation, pregnancy rates or perinatal complications has indeed been reported [8].…”