The need to improve patient care through discriminate use of intracytoplasmic sperm injection (ICSI) and improved understanding of spermatozoa, oocyte and embryo biology

Intracytoplasmic sperm injection (ICSI) for non-male factor indications: a committee opinion

Intracytoplasmic sperm injection, while typically effective for overcoming low or absent fertilization in couples with a clear abnormality of semen parameters, is frequently used in combination with assisted reproductive technologies for other etiologies of infertility in the presence of semen parameters that meet the World Health Organization 2010 normative reference values. This committee opinion provides a critical review of the literature, where available, to identify situations where this may or may not be of benefit. This document replaces the previously published document of the same name, last published in 2012 (Fertil Steril 2012;98:1395-9).

Use of intracytoplasmic sperm injection (ICSI) in normospermic men may result in lower clinical pregnancy and live birth rates

BACKGROUND

While intracytoplasmic sperm injection (ICSI) was developed for overcoming male infertility, it is increasingly being used for non-male factor indications, without consensus regarding the safety and efficacy of this approach.

AIMS

To determine whether ICSI offers any benefit compared to standard in vitro fertilisation (IVF), in the setting of normal semen parameters.

MATERIALS AND METHODS

Retrospective analysis of reproductive outcomes in 3363 stimulated cycles (IVF = 1661; ICSI = 1702), in patients treated between 2009-2015, was performed. Selected couples had no male factor infertility. Couples with abnormal semen parameters (based on WHO 2010 guidelines), presence of anti-sperm antibodies and low oocyte yield of ≤4 oocytes, were excluded. The outcomes analysed included: (1) fertilisation rate (FR); (2) clinical pregnancy rate (CPR); and (3) live birth rate (LBR), by method of fertilisation used (IVF vs ICSI) and controlling for significant confounders.

RESULTS

FR, CPR and LBR were significantly higher in the IVF group compared with ICSI (67.1% vs 62.3%, 23.06% vs 16.8%, 17.22% vs 13.2%, respectively). Pregnancy rate with ICSI was approximately 30% lower than with IVF, even when controlling for significant factors such as day of embryo transfer and number of embryos transferred. This translates to one less pregnancy in every 15 cycles where ICSI was used without clear indication.

CONCLUSIONS

Our data suggest that ICSI may be detrimental to clinical outcomes and contributes to the wider understanding of use of ICSI in normospermic men.

The influence of semen quality on male pronucleus demethylation process during ICSI cycle

There is growing evidence that the spermatozoon's epigenetic structure is of the utmost importance in the health of the future embryo. Following fertilization, sperm chromatin undergoes epigenetic reprogramming including DNA demethylation and remethylation, which resets gene expression. In some infertile patients, it is inevitable that sperm cells that are not within the range of normal human sperm parameters will be used for intracytoplasmic sperm injection. Understanding the relationship between the human sperm parameters and male pronucleus DNA demethylation seems necessary. We hypothesized that demethylation of the male pronucleus might be altered in zygotes conceived from a spermatozoa obtained from a sample exhibiting an abnormal semen analysis profile. To test the hypothesis, sperm cells from normal and abnormal human semen samples were injected into mouse oocytes. A group of cultured zygotes was fixed before the onset of DNA demethylation and the other group was fixed after DNA demethylation. Both groups were then labeled with a 5 methylcytosine antibody and the level of pronuclei methylation was detected as a function of fluorescent intensity. The level of demethylation was then determined as the difference between 5 methylcytosine fluorescent intensity before and after DNA demethylation. A negative correlation (p<0.05) was observed between sperm motility, morphology, percentage of head defects, protamine deficiency, and DNA demethylation level. However, no correlation was found between the demethylation level and sperm count. In conclusion, these observations suggest that demethylation is altered in the male pronucleus when low quality sperm samples are used.