Abstract
Twelve years ago, the introduction of motile sperm organelle morphology examination led to the development of a modified intracytoplasmic sperm injection procedure called intracytoplasmic morphologically selected sperm injection (IMSI) in which a spermatozoon selected under high magnification instead of 400× magnification is injected into an oocyte. Several studies found no correlation between IMSI and early embryo development in terms of fertilization while others found an increase in the fertilization rate. Conflicting results regarding the rates of implantation, pregnancy and abortion were also reported. A significant increase in the rate of top-quality embryos on days 3 and 5 was reported by the majority of the studies, and few failed to demonstrate a relationship between IMSI and embryo quality. Because of the extent of the population sizes and the diverse approaches and motile sperm organelle morphology examination classifications used by the studies reported thus far, definite conclusions on the consequences of vacuoles on embryo development cannot be drawn. More randomized controlled studies conducted by independent groups on large series are still needed, not only to identify the populations of patients that could benefit from the IMSI, but also to determine the efficacy of IMSI over intracytoplasmic sperm injection on the improvement of pregnancy outcomes.
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Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
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