Importance of real-time measurement of sperm head morphology in intracytoplasmic sperm injection

First-line infertility treatment in normal or subnormal sperm: Interest of a simplified pre-IMSI test

BACKGROUND

In the field of male infertility, when sperm is normal/subnormal, a few "add-on" routine tests can complete the basic semen examination.

OBJECTIVES

The aim of this study was to develop and evaluate a faster, simplified motile sperm organelle morphology examination (MSOME) technique for selected infertile patients with apparently normal/subnormal sperm and, in their background: failure of two or three intrauterine insemination (IUI) cycles, repeatedly fragmented embryos, embryonic development to blastocyst-stage failures, repeated miscarriages, a long period of infertility or 2 or more IVF attempts without pregnancy. Our test results were correlated with IUI, conventional in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and intracytoplasmic morphologically selected sperm injection (IMSI) outcomes.

MATERIALS AND METHODS

We validated an adapted version of the MSOME analysis called the pre-IMSI test (PIT), based on vacuole evaluation alone. 248 infertile patients from our assisted reproductive technology (ART) Center were retrospectively selected and split into three PIT score subgroups (patients with ≤8% (score I), 9 to 15% (score II) and ≥16% normal spermatozoa (score III)) based on the correlation between PIT results and each ART technique outcome. The choice of one or another of these ART techniques had been made according to the usual clinico-biological criteria.

RESULTS

Clinical outcomes for each of the three PIT subgroups were compared individually for the different ART techniques. For ICSI, the effect of the PIT score subgroup was significant for clinical pregnancies (p = 0.0054) and presented a trend for live births (p = 0.0614). Miscarriage rates of IVF attempts were statistically different depending on the PIT score (p = 0.0348). Furthermore, the odds ratios of clinical pregnancy rates were significantly different according to PIT score subgroup when comparing ICSI vs. IMSI or IVF vs. ICSI attempts.

DISCUSSION

IMSI appears to be recommended when sperm belongs to PIT score I, ICSI when it belongs to PIT score II and IVF or IUI when sperm is of PIT score III quality in selected infertile couples. The lack of statistical power in these PIT subgroups means that we must remain cautious in interpreting results.

CONCLUSION

Our results support the interest of this simplified test for certain couples with normal/subnormal sperm to help choose the most efficient ART technique, even as first-line treatment.

Evaluation of structural problems in the application of strict criteria for sperm morphology assessment

BACKGROUND

The WHO manual for basic semen analysis and ISO 23162 describe sperm morphology assessment as a standard part of semen analysis. Older studies showed a correlation between morphology results and (artificial) conception. In more recent studies this relationship was less apparent and there is more emphasis on sperm morphology as a marker for healthy spermatogenesis (and general male health). Meantime, many laboratories ceased morphology assessment, probably due to unfamiliarity with this paradigmatic shift and to technical difficulties in the assessment, like the interpretation of morphological criteria.

OBJECTIVES

The aim of this study was to identify morphological criteria with high variability in results in the Dutch External Quality Control (EQC) program.

MATERIAL AND METHODS

Over the period 2015-2020, a total of 72 photos of sperm cells along with dichotomous propositions based on 14 criteria as defined in WHO5 (2010) were distributed in the Dutch EQC program for semen analysis. The EQC results were evaluated for variability per criterion and for trends in time.

RESULTS

Between 2015 and 2020, 40 to 60 laboratories assessed the photos. Criteria with low variability between participants were related to acrosomal vacuoles, excessive residual cytoplasm, and tail metrics. In contrast, head ovality, regularity of head and midpiece contours, and alignment of the major axis of the midpiece and head led to the highest variability in outcomes. In general, there was a slightly positive trend (lower variability) in time, except for the criteria with the highest variability (stable or declining trend).

DISCUSSION AND CONCLUSION

This study indicates that there are (high) variabilities in the interpretation of the morphological criteria, leading to inconsistent outcomes of morphology assessment. The results are discussed from the perspective of imperfections in definitions and examples of the criteria as given in the WHO manuals.

Stain-Free Sperm Analysis and Selection for Intracytoplasmic Sperm Injection Complying with WHO Strict Normal Criteria

This multi-center study evaluated a novel microscope system capable of quantitative phase microscopy (QPM) for label-free sperm-cell selection for intracytoplasmic sperm injection (ICSI). Seventy-three patients were enrolled in four in vitro fertilization (IVF) units, where senior embryologists were asked to select 11 apparently normal and 11 overtly abnormal sperm cells, in accordance with current clinical practice, using a micromanipulator and 60× bright field microscopy. Following sperm selection and imaging via QPM, the individual sperm cell was chemically stained per World Health Organization (WHO) 2021 protocols and imaged via bright field microscopy for subsequent manual measurements by embryologists who were blinded to the QPM measurements. A comparison of the two modalities resulted in mean differences of 0.18 µm (CI -0.442-0.808 µm, 95%, STD-0.32 µm) for head length, -0.26 µm (CI -0.86-0.33 µm, 95%, STD-0.29 µm) for head width, 0.17 (CI -0.12-0.478, 95%, STD-0.15) for length-width ratio and 5.7 for acrosome-head area ratio (CI -12.81-24.33, 95%, STD-9.6). The repeatability of the measurements was significantly higher in the QPM modality. Surprisingly, only 19% of the subjectively pre-selected normal cells were found to be normal according to the WHO2021 criteria. The measurements of cells imaged stain-free through QPM were found to be in good agreement with the measurements performed on the reference method of stained cells imaged through bright field microscopy. QPM is non-toxic and non-invasive and can improve the clinical effectiveness of ICSI by choosing sperm cells that meet the strict criteria of the WHO2021.

Comment on 'Importance of real-time measurement of sperm head morphology in intracytoplasmic sperm injection' by Fumiaki Itoi et al

We present a commentary on the article published in the Zygote FirstView: 'Importance of real-time measurement of sperm head morphology in intracytoplasmic sperm injection' by Fumiaki Itoi and colleagues. We comment on the importance of providing the microscope setup details whenever sperm morphology visualization is discussed. The claim of ×6000-10,000 magnification is misleading as such levels of magnification are impossible to achieve.

Bibliometric analysis and visualization of literature on assisted reproduction technology

Introduction

Assisted reproductive technology (ART) is a method that uses various techniques to process sperm or ova. Assisted reproductive technology involves removing ova from a woman's ovaries, combining them with sperm in the laboratory, and returning them to the woman's body or donating them to another woman.

Methods

Based on the web of science core collection database, we firstly analyzed the quantity and quality of publications in the field of ART, secondly profiled the publishing groups in terms of country, institution, author's publication and cooperation network, and finally sorted out and summarized the hot topics of research.

Results

In total, 6,288 articles on ART were published between 2001 and 2022 in 1,013 journals. Most of these published articles represent the global research status, potential hotspots and future research directions. Publications and citations of research on assisted reproductive technology have steadily increased over the past few decades. Academic institutions in Europe and the United States have been leading in assisted reproductive technology research. The countries, institutions, journals, and authors with the most published articles were the United States (1864), Harvard Univ (108), Fertility and Sterility (819), and Stern, Judy E. (64). The most commonly used keywords are Assisted reproductive technology (3303) and in-vitro Fertilization (2139), Ivf (1140), Pregnancy (1140), Women (769), Intracytoplasmic Sperm injection (644), In Fertilization (632), Risk (545), and Outcome (423).

Conclusion

Frozen embryo transfer, intracytoplasmic sperm injection, and in vitro fertilization are the main research topics and hotspots in the field of assisted reproductive technology.