Teratozoospermia influences fertilization rate in vitro but not embryo quality

Novel modified criteria for sperm morphology in oocyte insemination could reduce ICSI rates without affecting IVF outcomes

OBJECTIVE

To evaluate the IVF outcomes of conventional insemination for less severe teratozoospermia (LST) patients (sperm morphology >2% and <4% normal forms and total motile sperm count ≥10 × 10⁶) and normal sperm patients defined by WHO criteria 2010 in the interest of reducing intracytoplasmic sperm injection (ICSI) rate in IVF.

MATERIALS AND METHODS

In this retrospective study, a total of 330 patients were recruited in the conventional IVF insemination. Among them, there were 76 patients in LST group and 254 patients in the normal sperm group. Fertilization rate, abnormal fertilization rate, embryo quality, implantation rate, chemical pregnancy rate, clinical pregnancy rate, abortion rate and live birth rate were assessed.

RESULTS

No statistical differences were achieved in the percentage of normally fertilized eggs (85.9% vs. 85.8%), abnormal fertilization rates of 1 PN (2.76% vs. 3.01%) or 3 PN (5.70% vs. 6.30%), good embryo rate (52.4% vs. 51.5%), implantation rate (20.9% vs 17.5%), chemical pregnancy rate (45.1% vs. 39.4%), clinical pregnancy rate (36.0% vs. 31.7%), live birth rate (28.9% vs. 26.7%) and abortion rate (9.6% vs. 10.2%) between LST group and normal sperm group regardless of the sperm morphology.

CONCLUSION

Patients with less severe teratozoospermia may not need ICSI in their IVF treatment since the outcomes particularly the fertilization rates were not affected by the less compromised sperm morphology at all when compared with the normal sperm patients.

The Effect of Teratozoospermia on Sex Chromosomes in Human Embryos

Purpose

The aim of this study is to evaluate the effect of abnormal semen morphology on the frequency of sex chromosomal abnormalities in embryos obtained by ICSI, which represents the first to be studied in Egyptian population.

Methods

Forty-two couples suffering from male infertility due to teratozoospermia were divided into two groups: patients with severe and moderate teratozoospermia (group A and B, respectively). All involved couples were subjected to careful history taking and had a normal clinical examination and karyotype. Females were subjected to hormonal assays, pelvic ultrasound, hysterosalpingography and yielded normal results, while male partners were subjected to computerized semen analysis. Preimplantation genetic diagnosis was performed for all suitably developed embryos including embryo biopsy, fixation of biopsied cells and fluorescent in situ hybridization (FISH) analysis.

Results

Couples included in the two groups were found to be homogenous in terms of age of both partners and duration of infertility. Interpretation of FISH results was performed by evaluation of embryos’ chromosomal constitution as regards abnormalities in chromosomes X, Y and 18. Twenty-seven embryos (48.2%) were found chromosomally abnormal in group A, while only 14 embryos (25.0%) were found chromosomally abnormal in group B. Aneuploidies involved only sex chromosomes were tripled in group A embryos when compared to their frequency in group B embryos (26.8% and 8.3%, respectively) with statistically significant difference between the two groups (p=0.002). Monosomies were the most common type of aneuploidy and were significantly higher in group A (14.3%) when compared to group B (3.6%) (p=0.047). Embryos with mosaic abnormalities were more common in group A (12.5%) when compared to group B (3.6%), however not statistically significantly different (p= 0.162). A significant difference between the two studied groups as regards the total number of potentially viable chromosomal abnormalities detected and the potentially viable sex chromosomal aneuploidies detected (p<0.001 and p=0.002), respectively.

Conclusion

The cases with severe teratozoospermia undergoing ICSI treatment can display a higher rate of sex chromosome aneuploidies in their embryos (threefold) than cases with moderate teratozoospermia.

Influence of sperm morphology on pregnancy outcome and offspring in in vitro fertilization and intracytoplasmic sperm injection: a matched case-control study

Sperm morphology was once believed as one of the most predictive indicators of pregnancy outcome in assisted reproductive technology (ART). However, the impact of teratozoospermia on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes and its offspring remains inconclusive. In order to evaluate the influence of teratozoospermia on pregnancy outcome and newborn status after IVF and ICSI, a retrospective study was conducted. This was a matched case-control study that included 2202 IVF cycles and 2574 ICSI cycles and was conducted at the Reproductive and Genetic Hospital of CITIC-Xiangya in Changsha, China, from June 2013 to June 2018. Patients were divided into two groups based on sperm morphology: teratozoospermia and normal sperm group. The pregnancy outcome and newborn outcome were analyzed. The results indicated that couples with teratozoospermia had a significantly lower optimal embryo rate compared to those with normal sperm morphology in IVF (P = 0.007), while there were no statistically significant differences between the two groups in terms of the fertilization rate, cleavage rate, implantation rate, and pregnancy rate (all P > 0.05). Additionally, teratozoospermia was associated with lower infant birth weight in multiple births after IVF. With regard to ICSI, there was no significant difference in both pregnancy outcome and newborn outcome between the teratozoospermia and normal groups (both P > 0.05). Furthermore, no increase in the risk of birth defects occurred in the teratozoospermia group after IVF/ICSI. Consequently, we believe that teratozoospermia has limited predictive value for pregnancy outcomes in IVF/ICSI, and has little impact on the resulting offspring if multiple pregnancy is avoided.

When to do intracytoplasmic sperm injection: a prospective comparison

PURPOSE

The purpose of the study was to assess the fertilization rate and embryo development in sibling human oocytes after split insemination in patients with and without isolated teratozoospermia.

METHODS

A prospective cohort study at a university affiliated reproduction center was performed. Hundred and three patients during the time periods 01-2013 to 12-2015 had split insemination ordered for their first IVF cycle. The primary outcome measured was fertilization rate. Secondary outcomes were the number and quality of embryos.

RESULTS

Mature oocytes at the time of collection were assigned as follows: 558 to IVF and 556 to ICSI. An additional 48 immature oocytes matured while awaiting spontaneous fertilization with IVF for a total of 606 in that group. The study group of normal strict sperm morphology ≤ 4 included 61 patients, and the control group included 42 patients with normal strict sperm morphology > 4. ICSI was statistically favored over IVF only in cases with normal strict sperm morphology ≤ 4%. There was a higher fertilization rate in ICSI compared to IVF (74.4% vs. 38%, p < 0.0001), a higher number of day 2 (4 ± 3.4 vs. 2.4 ± 2.7, p < 0.0001), day 3 (4 ± 3.4 vs. 2.2 ± 2.7, p < 0.0001) and day 5 embryos (2.2 ± 2.6 vs. 1.2 ± 2, p = 0.001), and they were of better quality; however, it did not reach significance (p = 0.062). A similar advantage for ICSI was seen in a subgroup of unexplained infertility with normal strict sperm morphology > 4%.

CONCLUSIONS

In conclusion, in couples with normal strict sperm morphology ≤ 4%, there is an advantage of ICSI over IVF in terms of fertilization rate, quantity and quality of cleavage stage embryos and blastocysts. Based on the results, ICSI seems reasonable as a first-line treatment in patients with normal strict sperm morphology ≤ 4%, as well as in patients with unexplained infertility.

Re-evaluation of the value of sperm morphology in classical in vitro fertilization in a Northeastern Chinese population

Objective

This study aimed to re-evaluate the clinical value of a 4% cut-off threshold of sperm morphology in in vitro fertilization (IVF) in a cohort of a Northeastern Chinese population.

Methods

A total of 375 IVF cycles that met strict inclusion criteria were included. These cycles were conducted with semen analysis and oocyte fertilization. A total of 188 embryo-transferred cycles proceeded. According to sperm morphology, 375 cycles were divided into group 1 (329 cycles, <4% normal sperm morphology rate [NSMR]) and group 2 (46 cycles, ≥4% NSMR), and 188 transferred cycles into group A (151 cycles, < 4% NSMR) and group B (37 cycles, ≥4% NSMR).

Results

The fertilization and normal fertilization rates were significantly lower in group 1 than in group 2. The normal fertilization rate was significantly correlated with an NSMR < 4% or ≥4%, but the fertilization rate was not significantly correlated with the NSMR. No significant differences were found in pregnancy outcomes between groups A and B.

Conclusions

This study suggests that infertile patients with an NSMR < 4% are more likely to have a poor normal fertilization status in IVF.

Sperm Morphology: History, Challenges, and Impact on Natural and Assisted Fertility

PURPOSE OF REVIEW

The classification of morphologically normal sperm has been progressively redefined. Concurrently, our understanding of the significance of sperm morphology in relation to male factor infertility has evolved. In this review, we will discuss the evolution of sperm morphology assessment and factors that contribute to its measurement variability. We will examine the impact of sperm morphology on natural pregnancy, IUI, IVF, and ICSI outcomes.

RECENT FINDINGS

There is a lack of consensus on sperm morphology classification, technique, and inter-observer grading variability. Current evidence suggests sperm morphology has low predictive value for pregnancy success, for both natural and assisted reproduction. Additionally, the threshold for what is considered an adequate percentage of morphologically normal sperm has changed over time. These variables have called into question the relevance of this variable in predicting fertility outcomes. Our understanding of the impact of sperm morphology on reproductive outcomes continues to evolve and seems to play less of a role than initially thought.

Outcome of conventional IVF and ICSI on sibling oocytes in the case of isolated teratozoospermia

PURPOSE

To reevaluate the effect of isolated teratozoospermia on IVF and determine if there was any therapeutic benefit to isolated teratozoospermia by ICSI, since there are no widely accepted criteria for the treatment technique about isolated teratozoospermia.

METHODS

A total of 441 couples with >20 million and progressive motility >30 % sperm undergoing their first IVF/ICSI cycle were included in the study between 2008 and 2010, for whom at least 8 oocytes were retrived. Isolated teratozoospermia was diagnosed in 183 of the included couples, and the rest couples (normal sperm morphology) were studied as control. Sibling oocytes were randomized to be inseminated either by ICSI or IVF. Fertilization rate, embryo quality, pregnancy rate, implantation rate and spontaneous abortion rate were assessed.

RESULTS

There was no difference in the percentage of eggs fertilized, implantation rate, pregnancy rate and spontaneous abortion rate between conventional IVF and ICSI regardless of the percentage of normal morphology. The day 3 embryonic morphology and rate of development were not different despite the insemination method and percentage of normal morphology.

CONCLUSION

Because isolated teratozoospermia did not influence the major indices of IVF and the unnecessary use of ICSI is time-consuming, costly and potential risks, couples with isolated teratozoospermia need not be subjected to ICSI.

The relationship between isolated teratozoospermia and clinical pregnancy after in vitro fertilization with or without intracytoplasmic sperm injection: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis of data from the literature from the years 1986 to 2009 using teratozoospermia and fertilization or IVF or in vitro fertilization as the keywords. A total of 31 studies were identified, and 4 met the inclusion criteria. Isolated teratozoospermia was not associated with a statistically significantly decreased probability of pregnancy with assisted reproduction.

Influence of oocytes and spermatozoa on early embryonic development

OBJECTIVE

To evaluate the effect of oocytes and spermatozoa on early embryonic development.

DESIGN

Retrospective study.

SETTING

Infertility Clinic, the Family Federation of Finland.

PATIENT(S)

Fifty-nine oocyte donation cycles with oocytes shared among 118 recipient couples.

INTERVENTION(S)

Culture of all fertilized oocytes.

MAIN OUTCOME MEASURE(S)

Standard sperm (concentration, progressive motility, and morphology according to Tygerberg strict criteria) and embryo (morphology and cleavage stage) characteristics.

RESULT(S)

A marked effect of the oocyte on both embryo morphology and blastomere cleavage rate was demonstrated. In addition, a significant sperm effect on blastomere cleavage rate was found. Sperm morphology as determined according to strict criteria rather than sperm count or progressive motility was positively associated with the blastomere cleavage rate. None of the measured sperm characteristics influenced embryo morphology.

CONCLUSION(S)

Embryo morphology, i.e., fragmentation and blastomere uniformity, are predominantly determined by oocyte quality, whereas both the oocyte and spermatozoa influence the blastomere cleavage rate.

[Predictive value of non-automated spermatic parameters and automated kinetic parameters on cleavage rate in fertilization in vitro]

The aim of this work was to determine retrospectively in 114 couples the predictive value of semen analysis for the in vitro fertilization (IVF) outcome when sperm evaluation before IVF was assessed by either conventional parameters or a Hamilton-Thorne automated motility analyser. A backward logistic regression analysis was used to study the relative contribution of each conventional or computerized parameter. Computerized sperm values were the worst index for predicting oocyte fertilization. However a tight relationship between morphology and cleavage ratio was observed. Using ROC analysis, under a 18% threshold, cleavage failure was noted in 71% of couples undergoing an IVF program. This study indicates that morphology is the best parameter for predicting cleavage failure.

Embryo score is a better predictor of pregnancy than the number of transferred embryos or female age

OBJECTIVE

To compare the value of 17 IVF variables, including a new mean score of transferred embryos (MSTE), in predicting pregnancy rate.

DESIGN

Retrospective study.

SETTING

Private IVF unit.

PATIENT(S)

Women who underwent 10,000 embryo transfers.

MAIN OUTCOME MEASURE(S)

Duration of infertility, type of infertility, female age, rank of IVF attempt, type of ovarian treatment, progesterone level, sperm count, sperm motility, sperm morphology, number of retrieved oocytes, number of mature oocytes, maturation rate, number of embryos obtained, fertilization rate, number of transferred embryos, cumulative embryo score (CES), mean score of transferred embryos (MSTE), and pregnancy rate.

RESULT(S)

Outcome of IVF-ET was significantly correlated with female age, type of infertility, number of retrieved oocytes, number of mature oocytes, maturation rate, embryos obtained, fertilization rate, transferred embryos, CES, and MSTE. Multivariate analysis demonstrated that MSTE was a better predictor of pregnancy than the number of transferred embryos and female age.

CONCLUSION(S)

Embryo quality is the best predictor of pregnancy. The embryo score described herein should be used in IVF-ET programs to choose the best embryos for transfer.

Osmotic effects on feline spermatozoa from normospermic versus teratospermic donors

Effects of osmolality stresses on the sperm of normospermic (>60% normal sperm/ejaculate) versus teratospermic (<40% normal sperm) domestic cats and the normospermic leopard cat and the teratospermic clouded leopard were studied. Spermatozoa were exposed to various anisotonic solutions in a single step or returned to near isotonic conditions in a single step after exposure to anisotonic solutions. The percentage of sperm motility was measured subjectively, and dual fluorescent stains were used to assess membrane integrity by flow cytometry. The percentage of sperm motility declined (P < 0.05) in domestic cat sperm exposed to osmolalities <200 and >450 mOsm. Spermatozoa from all felines underwent marked (P < 0.05) membrane disruption following a hypotonic stress, but sperm from teratospermic donors experienced greater (P < 0.05) membrane disruption in response to decreased osmolality. While feline spermatozoa appeared to be highly resistant to hypertonic (600, 1200, and 2400 mOsm) conditions, with >85% of the cells maintaining intact membranes, severe membrane disruption occurred when cells were returned to isotonicity in a single step. There was no difference (P > 0.05) between a 1- and 5-min exposure to various anisotonic solutions. Similarly, sperm from normospermic and teratospermic domestic cats responded identically after exposure to ionic or nonionic solute. Results demonstrate that: (1) spermatozoa from teratospermic males are more vulnerable to a hypotonic stress than sperm from normospermic counterparts; (2) in response to small deviations in osmolality, feline sperm experience a more rapid decline in motility than membrane integrity; and (3) an abrupt return to isotonicity after a hypertonic stress causes extensive sperm membrane damage regardless of ejaculate quality.

Fertilization, embryo quality, and cryosurvival in in vitro fertilization and intracytoplasmic sperm injection cycles

PURPOSE

Our purpose was to investigate the influence of semen quality on fertilization, embryo morphology, cleavage, and cryosurvival in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) programs.

METHODS

A retrospective analysis of 513 couples undergoing IVF and 255 couples undergoing ICSI was done.

RESULTS

Semen quality influenced fertilization in IVF and abnormal fertilization in IVF and ICSI, but no effects on the development, morphology, implantation capacity, or cryosurvival of embryos were found. Fertilization, embryo quality, and cryosurvival rates were similar after IVF and ICSI. The fertilization rate of mature oocytes in IVF was lower when cytoplasmic immaturity in the oocyte population was frequent. The speed of development of embryos was 2 hr faster after ICSI than after IVF. Two-cell-stage embryos survived best after cryopreservation with propanediol and sucrose on day 2.

CONCLUSIONS

After fertilization, semen parameters had no effect on the quality or cryosurvival of embryos in either IVF or ICSI.

Failure of fertilization following intracytoplasmic injection of round-headed sperm

BACKGROUND

Intracytoplasmic sperm injection (ICSI) is a very effective technique for the treatment of male factor infertility, even in severe cases. An exception to this rule is round-headed acrosomeless sperm, for which there is an extremely low success rate. The objective of this study was to report our first experience with ICSI using round-headed spermatozoa.

MATERIALS AND METHODS

A total of four infertile males with globozoospermia underwent the conventional ICSI program during the period from 1995 to 1997. Semen parameters were evaluated according to the WHO criteria. Twenty-eight oocytes were collected following conventional ovarian superovulation.

RESULTS

Volume, pH, and viscosity of the semen were within normal range. Sperm counts and progressive motility were from >1 to 90x10 6 mL, and from 0% to 60%, respectively. Distinct 100% acrosomeless morphology was observed with Giemsa staining. Twenty-two metaphase II oocytes (78.6% of the total) from four ICSI cases were injected with the husbandâs round-headed spermatozoa. Total fertilization failure was observed in all these cases.

CONCLUSION

The results clearly demonstrate the important role of normal head morphology in activating the oocytes, as well as the need to develop a modified but safe ICSI technique, which will be effective in overcoming this severe type of male infertility.