Y chromosome microdeletions, sperm DNA fragmentation and sperm oxidative stress as causes of recurrent spontaneous abortion of unknown etiology

Exploring Differentially Expressed Sperm miRNAs in Idiopathic Recurrent Pregnancy Loss and Their Association with Early Embryonic Development

The high incidence of idiopathic recurrent pregnancy loss (iRPL) may stem from the limited research on male contributory factors. Many studies suggest that sperm DNA fragmentation and oxidative stress contribute to iRPL, but their roles are still debated. MicroRNAs (miRNAs) are short non-coding RNAs that regulate various biological processes by modulating gene expression. While differential expression of specific miRNAs has been observed in women suffering from recurrent miscarriages, paternal miRNAs remain unexplored. We hypothesize that analyzing sperm miRNAs can provide crucial insights into the pathophysiology of iRPL. Therefore, this study aims to identify dysregulated miRNAs in the spermatozoa of male partners of iRPL patients. Total mRNA was extracted from sperm samples of iRPL and control groups, followed by miRNA library preparation and high-output miRNA sequencing. Subsequently, raw sequence reads were processed for differential expression analysis, target prediction, and bioinformatics analysis. Twelve differentially expressed miRNAs were identified in the iRPL group, with eight miRNAs upregulated (hsa-miR-4454, hsa-miR-142-3p, hsa-miR-145-5p, hsa-miR-1290, hsa-miR-1246, hsa-miR-7977, hsa-miR-449c-5p, and hsa-miR-92b-3p) and four downregulated (hsa-miR-29c-3p, hsa-miR-30b-5p, hsa-miR-519a-2-5p, and hsa-miR-520b-5p). Functional enrichment analysis revealed that gene targets of the upregulated miRNAs are involved in various biological processes closely associated with sperm quality and embryonic development.

A prospective cohort study of preconception COVID-19 vaccination and miscarriage

STUDY QUESTION

To what extent is preconception maternal or paternal coronavirus disease 2019 (COVID-19) vaccination associated with miscarriage incidence?

SUMMARY ANSWER

COVID-19 vaccination in either partner at any time before conception is not associated with an increased rate of miscarriage.

WHAT IS KNOWN ALREADY

Several observational studies have evaluated the safety of COVID-19 vaccination during pregnancy and found no association with miscarriage, though no study prospectively evaluated the risk of early miscarriage (gestational weeks [GW] <8) in relation to COVID-19 vaccination. Moreover, no study has evaluated the role of preconception vaccination in both male and female partners.

STUDY DESIGN, SIZE, DURATION

An Internet-based, prospective preconception cohort study of couples residing in the USA and Canada. We analyzed data from 1815 female participants who conceived during December 2020-November 2022, including 1570 couples with data on male partner vaccination.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible female participants were aged 21-45 years and were trying to conceive without use of fertility treatment at enrollment. Female participants completed questionnaires at baseline, every 8 weeks until pregnancy, and during early and late pregnancy; they could also invite their male partners to complete a baseline questionnaire. We collected data on COVID-19 vaccination (brand and date of doses), history of SARS-CoV-2 infection (yes/no and date of positive test), potential confounders (demographic, reproductive, and lifestyle characteristics), and pregnancy status on all questionnaires. Vaccination status was categorized as never (0 doses before conception), ever (≥1 dose before conception), having a full primary sequence before conception, and completing the full primary sequence ≤3 months before conception. These categories were not mutually exclusive. Participants were followed up from their first positive pregnancy test until miscarriage or a censoring event (induced abortion, ectopic pregnancy, loss to follow-up, 20 weeks' gestation), whichever occurred first. We estimated incidence rate ratios (IRRs) for miscarriage and corresponding 95% CIs using Cox proportional hazards models with GW as the time scale. We used propensity score fine stratification weights to adjust for confounding.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 1815 eligible female participants, 75% had received at least one dose of a COVID-19 vaccine by the time of conception. Almost one-quarter of pregnancies resulted in miscarriage, and 75% of miscarriages occurred <8 weeks' gestation. The propensity score-weighted IRR comparing female participants who received at least one dose any time before conception versus those who had not been vaccinated was 0.85 (95% CI: 0.63, 1.14). COVID-19 vaccination was not associated with increased risk of either early miscarriage (GW: <8) or late miscarriage (GW: 8-19). There was no indication of an increased risk of miscarriage associated with male partner vaccination (IRR = 0.90; 95% CI: 0.56, 1.44).

LIMITATIONS, REASONS FOR CAUTION

The present study relied on self-reported vaccination status and infection history. Thus, there may be some non-differential misclassification of exposure status. While misclassification of miscarriage is also possible, the preconception cohort design and high prevalence of home pregnancy testing in this cohort reduced the potential for under-ascertainment of miscarriage. As in all observational studies, residual or unmeasured confounding is possible.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to evaluate prospectively the relation between preconception COVID-19 vaccination in both partners and miscarriage, with more complete ascertainment of early miscarriages than earlier studies of vaccination. The findings are informative for individuals planning a pregnancy and their healthcare providers.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Health [R01-HD086742 (PI: L.A.W.); R01-HD105863S1 (PI: L.A.W. and M.L.E.)], the National Institute of Allergy and Infectious Diseases (R03-AI154544; PI: A.K.R.), and the National Science Foundation (NSF-1914792; PI: L.A.W.). The funders had no role in the study design, data collection, analysis and interpretation of data, writing of the report, or the decision to submit the paper for publication. L.A.W. is a fibroid consultant for AbbVie, Inc. She also receives in-kind donations from Swiss Precision Diagnostics (Clearblue home pregnancy tests) and Kindara.com (fertility apps). M.L.E. received consulting fees from Ro, Hannah, Dadi, VSeat, and Underdog, holds stock in Ro, Hannah, Dadi, and Underdog, is a past president of SSMR, and is a board member of SMRU. K.F.H. reports being an investigator on grants to her institution from UCB and Takeda, unrelated to this study. S.H.-D. reports being an investigator on grants to her institution from Takeda, unrelated to this study, and a methods consultant for UCB and Roche for unrelated drugs. The authors report no other relationships or activities that could appear to have influenced the submitted work.

TRIAL REGISTRATION NUMBER

N/A.

Differential Sperm Proteomics Reveals the Significance of Fatty Acid Synthase and Clusterin in Idiopathic Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is a pervasive health issue affecting a large number of couples globally, which leads to increased emotional and financial strain on the affected families. While female factors have been extensively studied and are well known, the contribution of male factors to RPL remains largely unknown. As high as 40% of RPL cases are unexplained, which are termed as idiopathic RPL (iRPL), necessitating the investigation of male factors. The role of spermatozoa in early embryonic development is now well established, and recent research studies have shown that oxidative stress and DNA fragmentation in sperm cells are linked to RPL. The aim of this study was to identify proteomic markers of iRPL in human spermatozoa using tandem mass spectrometry. A label-free method quantified a total of 1820 proteins, and statistical analysis identified 359 differentially expressed proteins, the majority of which were downregulated in iRPL samples (344). Bioinformatics analysis revealed that proteomic alterations were mainly associated with biological processes such as response to stress, protein folding, chromatin organization, DNA conformation change, oxidative phosphorylation, and electron transport chain. In coherence with past studies, we determined fatty acid synthase (FASN) and clusterin (CLU) to be the most potential sperm markers for iRPL and confirmed their expression changes in iRPL by western blotting. Conclusively, we believe that FASN and CLU might serve as potential markers of iRPL and suggest exploratory functional studies to identify their specific role in pregnancy loss.

Male Contributory Factors in Recurrent Pregnancy Loss

With 40% of idiopathic cases, recurrent pregnancy loss (RPL) is a problem of great concern for patients and clinicians. In addition to financial burden, it causes a lot of frustration and anxiety in affected couples. The primary objective of this review was to gain knowledge of recent advances in the field of recurrent pregnancy losses and to understand the role of male contributory factors in idiopathic cases. For a long time, researchers and clinicians were seeking an explanation for idiopathic RPL (iRPL) in females only; however, with recent advances in reproductive biology, the role of spermatozoa in early embryonic development has caught the attention of researchers. Clinically, only routine semen parameters and karyotyping are investigated in iRPL male partners, which seem to be insufficient in the present scenario, and thus, more information at the molecular level is required for a comprehensive understanding of iRPL. In concluding remarks, we suggest targeted multi-omics investigations in a large cohort to improve our understanding of the role of male contributory factors in iRPL.

The Role of Seminal Oxidative Stress in Recurrent Pregnancy Loss

Recurrent pregnancy loss is a distressing condition affecting 1–2% of couples. Traditionally investigations have focused on the female, however more recently researchers have started to explore the potential contribution of the male partner. Seminal reactive oxygen species have a physiological function in male reproduction but in excess are suspected to generate structural and functional damage to the sperm. Evidence is mounting to support an association between elevated seminal reaction oxygen species and recurrent pregnancy loss. Studies suggest that the rates of sperm DNA damage are higher in the male partners of women affected by recurrent pregnancy loss compared with unaffected men. However, the available pool of data is conflicting, and interpretation is limited by the recent change in nomenclature and the heterogeneity of study methodologies. Furthermore, investigation into the effects of oxidative stress on the epigenome show promise. The value of antioxidant therapy in the management of recurrent pregnancy loss currently remains unclear.

Association of male factors with recurrent pregnancy loss

The role of male factors in recurrent pregnancy loss (RPL) is receiving increased attention since sperm quantity and quality, male genetic mutations, as well as epigenetic modifications, have all been associated with RPL. A growing number of studies have been published on the relationship between male factors and RPL; however, these reports are limited due to small sample sizes, inconsistent inclusion criteria, and detection methods. Herein, we investigate the effects of several male factors on RPL from a genetic and non-genetic perspective to aid clinicians in determining the etiology and optimal treatment strategy for patients with RPL.

Influence of sperm DNA fragmentation on the clinical outcome of in vitro fertilization-embryo transfer (IVF-ET)

PURPOSE

To evaluate the effect of elevated sperm DNA fragmentation index (DFI) on fresh and frozen embryo transfer cycles.

METHODS

A retrospective study was performed with 549 fresh embryo transfer cycles and 1340 frozen embryo transfer cycles after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) from 2016 to 2021.

RESULTS

The statistical results of 549 fresh embryo transfer cycles showed that the delivery rate in the normal sperm DFI group (43.9% vs. 27.1%, P = 0.014) was significantly higher than that in the abnormal sperm DFI group, and there were no significant differences in the biochemical pregnancy rate (59.0% vs. 50.8%, P = 0.232), clinical pregnancy rate (53.1% vs. 40.7%, P = 0.072), or miscarriage rate (17.3% vs. 33.3%, P = 0.098) between the two groups. The results of 1340 frozen embryo transfer cycles showed that the biochemical pregnancy rate (57.9% vs. 45.6%, P = 0.006) and clinical pregnancy rate (50.3% vs. 40.7%, P = 0.027) in the normal sperm DFI group were significantly higher than those in the abnormal sperm DFI group. The delivery rate (40.9% vs. 33.3%, P = 0.074) and miscarriage rate (18.6% vs. 18.0%, P = 0.919) were not significantly different between the two groups.

CONCLUSION

The increase of sperm DFI significantly reduced the delivery rate of fresh embryo transfer cycles and the biochemical pregnancy rate and clinical pregnancy rate of frozen embryo transfer cycles.

Label-free proteomics of spermatozoa identifies candidate protein markers of idiopathic recurrent pregnancy loss

Recurrent pregnancy loss (RPL) affects a large number of couples worldwide, increasing their mental and financial burdens. While female factors that contribute to RPL have been studied extensively, the role of male factors is largely unknown, and approximately 40 % RPL cases remain unexplained despite thorough clinical examinations. These cases are clinically termed as idiopathic RPL (iRPL). Several studies have recently found that spermatozoa play an important role, beyond fertilization, in iRPL, specifically in early embryonic development. Consequently, scientists explored spermatozoa to understand iRPL and revealed that both oxidative stress and DNA fragmentation contribute to RPL. In this study, we analyzed sperm samples from male partners of iRPL patients and fertile men who recently fathered a child by LC-MS/MS to identify proteomic markers of iRPL. A total of 1,988 proteins were quantified by a label-free method, and stringent statistical analysis was performed for the selection of candidate biomarkers of iRPL. Out of 1,647 proteins quantified, only 7 proteins qualified the selection criteria, which are lactotransferrin, ATP synthase subunit beta mitochondrial, fatty acid synthase, anterior gradient protein 2 homolog, hemoglobin subunit beta, short-chain specific acyl-CoA dehydrogenase mitochondrial, cytoplasmic dynein 1 heavy chain, and 14-3-3 protein sigma. We then performed gene annotations, pathways, and network analyses to gain more biological insights, identifying an association between oxidative stress and iRPL.

Sperm DNA fragmentation in Chinese couples with unexplained recurrent pregnancy loss

We aimed to study the association between sperm DNA fragmentation and recurrent pregnancy loss (RPL) in the Chinese population via a retrospective observational study of Chinese couples who had experienced RPL between May 2013 and August 2018. The study population included 461 men from couples with RPL and 411 men from a control group (couples with clinical pregnancy via in vitro fertilization owing to female causes). Routine semen analysis, sperm chromatin analysis, and microscopic (high-power) morphological analysis were performed using semen samples. Semen samples were assessed for volume, sperm count, and motility. The sperm DNA fragmentation index (DFI) was calculated, and the median DFI was obtained. Men were categorized as having normal (37.8%; DFI ≤ 15.0%), moderate (33.6%; 15.0% < DFI < 30.0%), or severe (28.6%; DFI ≥ 30.0%) DNA fragmentation levels. The percentage of men with severe DNA fragmentation was significantly higher in the RPL (42.3%) group than that in the control group (13.1%), whereas the percentage of men with normal levels of DNA fragmentation was significantly lower in the RPL group (22.8%) than that in the control group (54.7%). Subsequent analysis also demonstrated that the sperm DNA fragmentation rate had a moderate reverse correlation with the sperm progressive motility rate (r = −0.47, P < 0.001) and the total motile sperm count (r = −0.31, P < 0.001). We found a positive correlation between RPL and sperm DNA fragmentation. The results suggest that increased sperm DNA damage is associated with RPL.

Male sperm quality and risk of recurrent spontaneous abortion in Chinese couples: A systematic review and meta-analysis

OBJECTIVE

To assess the association of conventional semen parameters and sperm DNA fragmentation with risk of recurrent spontaneous abortion (RSA).

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENTS

Total 1,690 male partners of women with RSA, and 1,337 male partners of fertile control women.

INTERVENTIONS

Case-control or cohort studies were determined by searching PubMed, Google Scholar, Cochrane Libraries, China Biology Medicine disc, Chinese Scientific Journals Fulltext Database, China National Knowledge Infrastructure, and Wanfang Database. RSA was defined as two or more previous pregnancy losses. The fertile women refer to the reproductive women who have had at least a normal pregnancy history and no history of abortion.

MAIN OUTCOME MEASURES

This study included eight outcome measures: semen volume(ml), semen pH value, sperm density(106/ml), sperm viability (%), sperm progressive motility rate (%), normal sperm morphology rate (%), sperm deformity rate(%), sperm DNA fragmentation index (DFI) (%). The summary measures were reported as standardized mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Finally, twenty-four studies were included for analysis. Overall, male partners of women with RSA had a significantly lower level of sperm density (SMD = -0.53, 95%CI: - 0.75 to -0.30), sperm viability (SMD = -1.03, 95%CI: - 1.52 to -0.54), sperm progressive motility rate (SMD = -0.76, 95%CI:-1.06 - -0.46), and normal sperm morphology rate (SMD =  -0.56, 95%CI: - 0.99 to -0.12), and had a significantly higher rate of sperm deformity rate (SMD = 1.29, 95%CI: 0.60 - 1.97), and sperm DFI (SMD = 1.60, 95%CI: 1.04 to 2.17), when compared with the reference group. However, there were no statistically significant differences for semen volume (SMD = -0.03, 95%CI: -0.14 - 0.08) and semen pH value (SMD =  -0.23, 95% CI: -0.50 to 0.05) among 2 groups.

CONCLUSIONS

The results of this analysis support an association of sperm density, sperm viability, sperm progressive motility rate, normal sperm morphology rate, sperm deformity rate, as well as sperm DFI with RSA. However, given the significant heterogeneity between studies and the lack of more detailed data on the subjects, further large-scale prospective studies are needed.

The effects of Y chromosome microdeletions on in vitro fertilization outcomes, health abnormalities in offspring and recurrent pregnancy loss

Male factor infertility accounts for approximately 50% of all infertility evaluations. A common cause of severe oligozoospermia and azoospermia is Y chromosome microdeletions (YCMs). Men with these genetic microdeletions must typically undergo assisted reproductive technology (ART) procedures to obtain paternity. In this review, we performed a thorough and extensive search of the literature to summarize the effects of YCMs on in vitro fertilization (IVF) outcomes, health abnormalities in offspring and recurrent pregnancy loss (RPL). The PubMed database was searched using specific search terms and papers were identified using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Sperm retrieval amongst men with complete AZFa and/or AZFb deletions is extremely rare and thus data on ARTs is largely unavailable. In AZFc-deleted men undergoing assisted reproduction, the collective fertilization rate (FR) is 59.8%, the clinical pregnancy rate is 28.6% and the live birth rate is 23.4%. When successful, the YCM is always transmitted to the male offspring and the deletion size either remains unchanged or widens. YCMs generally result in decreased fertilization, clinical pregnancy and live birth rates compared to men with intact Y chromosomes during ART interventions. There is a minimal or absent association of YCMs with abnormalities in the offspring or RPL.

Sperm DNA Fragmentation: A New Guideline for Clinicians

Sperm DNA integrity is crucial for fertilization and development of healthy offspring. The spermatozoon undergoes extensive molecular remodeling of its nucleus during later phases of spermatogenesis, which imparts compaction and protects the genetic content. Testicular (defective maturation and abortive apoptosis) and post-testicular (oxidative stress) mechanisms are implicated in the etiology of sperm DNA fragmentation (SDF), which affects both natural and assisted reproduction. Several clinical and environmental factors are known to negatively impact sperm DNA integrity. An increasing number of reports emphasizes the direct relationship between sperm DNA damage and male infertility. Currently, several assays are available to assess sperm DNA damage, however, routine assessment of SDF in clinical practice is not recommended by professional organizations. This article provides an overview of SDF types, origin and comparative analysis of various SDF assays while primarily focusing on the clinical indications of SDF testing. Importantly, we report four clinical cases where SDF testing had played a significant role in improving fertility outcome. In light of these clinical case reports and recent scientific evidence, this review provides expert recommendations on SDF testing and examines the advantages and drawbacks of the clinical utility of SDF testing using Strength-Weaknesses-Opportunities-Threats (SWOT) analysis.

Sperm DNA fragmentation valued by SCSA and its correlation with conventional sperm parameters in male partner of recurrent spontaneous abortion couple

The objective of this study is to evaluate the predictive value of sperm DNA fragmentation Index (DFI) in unexplained recurrent spontaneous abortion (RSA) and to investigate its correlation with conventional sperm parameters. Besides, we aimed to reveal the necessity of establishing a DFI clinical threshold of each laboratory for the prognostic diagnosis of RSA and establish our own DFI threshold. Semen samples were collected from male partners of RSA patients (n = 139) and healthy recent fathers (control, n = 200). DFI was tested using SCSA and conventional semen analysis was performed using an automatic semen analyzer. The DFI value and distribution were compared between the two groups using corresponding statistical software. The diagnostic threshold value was established by ROC curve. The correlation between DFI and the conventional semen parameters of the 139 cases was further analyzed using Student's t test and Mann-Whitney U test. Our result showed that DFI was significantly higher in RSA patients compared with normal donor controls. We established our own DFI threshold at 13.59%. There was only a weak partial correlation between DFI values and conventional sperm analysis parameters. Our present study suggested that DFI might be used as a valuable predictor for RSA independent of conventional sperm parameters. Additionally, we recommend that each laboratory should establish its own clinical DFI threshold for more precise prediction of RSA and we recommend that sperm DNA fragmentation test should be included in complete sperm quality assessment in addition to conventional semen analysis for RSA male partners.

Association between sperm DNA fragmentation and idiopathic recurrent pregnancy loss: a systematic review and meta-analysis

Sperm DNA fragmentation (sDF) has emerged as a valuable tool for evaluating male fertility, yet the relationship between DNA fragmentation in the male gamete and idiopathic recurrent pregnancy loss (RPL) remains a topic of ongoing debate. Hence, a meta-analysis was conducted of 12 prospective and 2 retrospective studies involving 530 men with a history of RPL who underwent sDF testing compared with 639 fertile control participants. The main outcome measures were sDF measured by comet assay, TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labelling (TUNEL), sperm chromatin dispersion (SCD) or sperm chromatin structure assay. Overall, couples with a history of idiopathic RPL demonstrated higher levels of sDF than fertile couples (average mean difference 11.98, P < 0.001). Subgroup analysis demonstrated a similar average mean difference between the RPL and control groups using SCD compared with TUNEL, while mean paternal age and mean sperm motility in the RPL groups tested by meta-regression demonstrated no significant effect on the mean differences in sDF (P > 0.10). These results support the diagnostic value of sDF over standard semen analysis, as well as a possible paternally derived genetic origin of unexplained RPL. Further prospective studies are required to further assess the predictive utility of sDF for assessing couples with unexplained RPL.

Cellular and molecular mechanisms of sulfur mustard toxicity on spermatozoa and male fertility

Sulfur mustard (SM) is a toxic compound that can target human spermatozoa. SM induces a wide variety of pathological effects in human reproductive organs, including sexual hormone disturbance, testicular atrophy, impaired spermatogenesis, poor sperm quality, defects in embryo development, childhood physical abnormalities, and severe fertility problems. However, the molecular and cellular mechanisms of SM action on male reproductive health and human sperm function are unclear. Excessive production of reactive oxygen species and the resulting oxidative stress is likely a significant mechanism of SM action, and could be associated with sperm DNA damage, membrane lipid peroxidation, reduced membrane fluidity, mitochondrial deficiency, apoptosis, and poor sperm quality. In this review, we aim to discuss the cellular and molecular mechanisms of SM action on sperm and reproductive health, the significance of OS, and the mechanisms through which SM enhances the infertility rate among SM-exposed individuals.

Mechanisms of diazinon effects on impaired spermatogenesis and male infertility

Diazinon (DZN) is an organophosphate insecticide that has cytotoxic and pathological effects on the reproductive system. It causes a wide variety of pathological effects on the reproductive system such as testicular atrophy, disturbance in sex hormones, impaired spermatogenesis, low quality of sperm, and fertility problems. However, molecular and cellular mechanisms of its adverse effects are not well understood. General events such as testicular damage, inflammation, mitochondrial deficiency, DNA fragmentation, disintegration of sperm plasma membrane, apoptosis, and cell death are observed in DZN-exposed animals. Oxidative stress (OS) induced by reactive oxygen species may be a main mechanism, which can be associated with sperm DNA fragmentation, reduced integrity of sperm cell membrane, apoptosis, depletion of antioxidants, and subsequently poor sperm quality and male infertility. Therefore, identification of these pathways may provide valuable information regarding the mechanisms of DZN action on the male reproductive system. In this review, we aim to discuss the proposed cellular and molecular mechanisms of DZN action on male reproductive system, the importance of OS and mechanisms by which DZN induces OS and depletion of other antioxidants.

Interventions for investigating and identifying the causes of stillbirth

BACKGROUND

Identification of the causes of stillbirth is critical to the primary prevention of stillbirth and to the provision of optimal care in subsequent pregnancies. A wide variety of investigations are available, but there is currently no consensus on the optimal approach. Given their cost and potential to add further emotional burden to parents, there is a need to systematically assess the effect of these interventions on outcomes for parents, including psychosocial outcomes, economic costs, and on rates of diagnosis of the causes of stillbirth.

OBJECTIVES

To assess the effect of different tests, protocols or guidelines for investigating and identifying the causes of stillbirth on outcomes for parents, including psychosocial outcomes, economic costs, and rates of diagnosis of the causes of stillbirth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (31 August 2017), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (15 May 2017).

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs), quasi-RCTs, and cluster-RCTs. We planned to include studies published as abstract only, provided there was sufficient information to allow us to assess study eligibility. We planned to exclude cross-over trials.Participants included parents (including mothers, fathers, and partners) who had experienced a stillbirth of 20 weeks' gestation or greater.This review focused on interventions for investigating and identifying the causes of stillbirth. Such interventions are likely to be diverse, but could include:* review of maternal and family history, and current pregnancy and birth history;* clinical history of present illness;* maternal investigations (such as ultrasound, amniocentesis, antibody screening, etc.);* examination of the stillborn baby (including full autopsy, partial autopsy or noninvasive components, such as magnetic resonance imaging (MRI), computerised tomography (CT) scanning, and radiography);* umbilical cord examination;* placental examination including histopathology (microscopic examination of placental tissue); and* verbal autopsy (interviews with care providers and support people to ascertain causes, without examination of the baby).We planned to include trials assessing any test, protocol or guideline (or combinations of tests/protocols/guidelines) for investigating the causes of stillbirth, compared with the absence of a test, protocol or guideline, or usual care (further details are presented in the Background, see Description of the intervention).We also planned to include trials comparing any test, protocol or guideline (or combinations of tests/protocols/guidelines) for investigating the causes of stillbirth with another, for example, the use of a limited investigation protocol compared with a comprehensive investigation protocol.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility independently.

MAIN RESULTS

We excluded five studies that were not RCTs. There were no eligible trials for inclusion in this review.

AUTHORS' CONCLUSIONS

There is currently a lack of RCT evidence regarding the effectiveness of interventions for investigating and identifying the causes of stillbirth. Seeking to determine the causes of stillbirth is an essential component of quality maternity care, but it remains unclear what impact these interventions have on the psychosocial outcomes of parents and families, the rates of diagnosis of the causes of stillbirth, and the care and management of subsequent pregnancies following stillbirth. Due to the absence of trials, this review is unable to inform clinical practice regarding the investigation of stillbirths, and the specific investigations that would determine the causes.Future RCTs addressing this research question would be beneficial, but the settings in which the trials take place, and their design, need to be given careful consideration. Trials need to be conducted with the utmost care and consideration for the needs, concerns, and values of parents and families. Assessment of longer-term psychosocial variables, economic costs to health services, and effects on subsequent pregnancy care and outcomes should also be considered in any future trials.

Sperm aneuploidy and DNA fragmentation in unexplained recurrent pregnancy loss: a multicenter case-control study

Background

Recurrent pregnancy loss (RPL) is defined as the loss of at least three pregnancies in the first trimester. Although the most common cause is embryo aneuploidy, and despite female checkup and couple karyotyping, in about 50% of cases RPL remain unexplained. Male implication has little been investigated and results are discordant. In this context, we conducted a multi-center prospective case-control study to investigate male gamete implication in unexplained RPL.

Methods

A total of 33 cases and 27 controls were included from three university hospitals. We investigated environmental and family factors with a detailed questionnaire and andrological examination, sperm characteristics, sperm DNA/chromatin status using the sperm chromatin structure assay (SCSA) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and sperm aneuploidy using fluorescence in situ hybridization (FISH). The Mann-Whitney test and the Wilcoxon or Fisher exact tests were used. A non-parametric Spearman correlation was performed in order to analyze the relationship between various sperm parameters and FISH and sperm DNA fragmentation results.

Results

We found significant differences between cases and controls in time to conceive, body mass index (BMI), family history of infertility and living environment. In cases, total sperm motility and the percentage of morphologically normal spermatozoa were significantly decreased. No difference was found between cases and controls in sperm DNA fragmentation or chromatin integrity. In cases, spermatozoa with aneuploidy, hyperhaploidy and chromosome 18 disomy were significantly increased.

Conclusions

This prospective case-control study is one of the largest to examine environmental factors, sperm characteristics, sperm DNA fragmentation and chromatin, and chromosome anomalies in spermatozoa in relation to unexplained recurrent pregnancy loss. The originality of our study lies in the comprehensive andrological examination and search for risk factors and fertility history. Further studies are needed to confirm the links between unexplained RPL and a male family history of infertility or miscarriages. The increased sperm aneuploidy observed in unexplained RPL supports a male etiology. These data pave the way for further studies to demonstrate the value of preimplantation genetic screening in men with increased sperm aneuploidy whose partners experience unexplained RPL.

Sperm DNA fragmentation, recurrent implantation failure and recurrent miscarriage

Evidence is increasing that the integrity of sperm DNA may also be related to implantation failure and recurrent miscarriage (RM). To investigate this, the sperm DNA fragmentation in partners of 35 women with recurrent implantation failure (RIF) following in vitro fertilization, 16 women diagnosed with RM and seven recent fathers (control) were examined. Sperm were examined pre- and post-density centrifugation by the sperm chromatin dispersion (SCD) test and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. There were no significant differences in the age of either partner or sperm concentration, motility or morphology between three groups. Moreover, there were no obvious differences in sperm DNA fragmentation measured by either test. However, whilst on average sperm DNA fragmentation in all groups was statistically lower in prepared sperm when measured by the SCD test, this was not seen with the results from the TUNEL assay. These results do not support the hypothesis that sperm DNA fragmentation is an important cause of RIF or RM, or that sperm DNA integrity testing has value in such patients. It also highlights significant differences between test methodologies and sperm preparation methods in interpreting the data from sperm DNA fragmentation tests.

DNA Double Strand Break Response and Limited Repair Capacity in Mouse Elongated Spermatids

Spermatids are extremely sensitive to genotoxic exposures since during spermiogenesis only error-prone non homologous end joining (NHEJ) repair pathways are available. Hence, genomic damage may accumulate in sperm and be transmitted to the zygote. Indirect, delayed DNA fragmentation and lesions associated with apoptotic-like processes have been observed during spermatid elongation, 27 days after irradiation. The proliferating spermatogonia and early meiotic prophase cells have been suggested to retain a memory of a radiation insult leading later to this delayed fragmentation. Here, we used meiotic spread preparations to localize phosphorylate histone H2 variant (γ-H2AX) foci marking DNA double strand breaks (DSBs) in elongated spermatids. This technique enabled us to determine the background level of DSB foci in elongated spermatids of RAD54/RAD54B double knockout (dko) mice, severe combined immunodeficiency SCID mice, and poly adenosine diphosphate (ADP)-ribose polymerase 1 (PARP1) inhibitor (DPQ)-treated mice to compare them with the appropriate wild type controls. The repair kinetics data and the protein expression patterns observed indicate that the conventional NHEJ repair pathway is not available for elongated spermatids to repair the programmed and the IR-induced DSBs, reflecting the limited repair capacity of these cells. However, although elongated spermatids express the proteins of the alternative NHEJ, PARP1-inhibition had no effect on the repair kinetics after IR, suggesting that DNA damage may be passed onto sperm. Finally, our genetic mutant analysis suggests that an incomplete or defective meiotic recombinational repair of Spo11-induced DSBs may lead to a carry-over of the DSB damage or induce a delayed nuclear fragmentation during the sensitive programmed chromatin remodeling occurring in elongated spermatids.

Increased chromosome 16 disomy rates in human spermatozoa and recurrent spontaneous abortions

OBJECTIVE

To investigate if unexplained recurrent spontaneous abortions (RSA) are associated with increased rates of aneuploidy in spermatozoa of RSA partners ("RSA-men").

DESIGN

Case-control study.

SETTING

Academic research center.

PATIENT(S)

Patients enrolled at the Hormone and Fertility Center and controls at the Department of Urology (LMU-Munich).

INTERVENTION(S)

Sperm samples of 11 partners of unexplained RSA cases evaluated for elevated diploidy and disomy levels of chromosomes 1-22, X, and Y by multicolor sperm fluorescence in situ hybridization (FISH).

MAIN OUTCOME MEASURE(S)

Aneuploidy rates obtained in RSA-men compared with controls from the literature and internally; an increase of the aneuploidy rate was considered statistically significant, when it differed ≥ 2 standard deviations from the mean baseline level in controls.

RESULT(S)

Our sperm FISH data on RSA men showed increased disomy rates for at least three chromosomes in more than 60% of patients but no statistically significant increase of the overall mean sperm disomy or diploidy rate. In particular, meiotic errors involving chromosome 16 contributed to increased sperm disomy in more than 60% of our patients.

CONCLUSION(S)

These data suggest that among paternal meiotic errors nondisjunction of chromosome 16 might have similar relative influence on fetal aneuploidy compared with maternal chromosome 16 disomy.

Sperm DNA fragmentation abnormalities in men from couples with a history of recurrent miscarriage

BACKGROUND

Previous studies have described an association between sperm with DNA damage and a history of recurrent miscarriage (RM), although it is not clear whether there is benefit in screening for sperm DNA fragmentation and to what extent DNA fragmentation impacts upon RM.

AIMS

To identify what proportion of couples experiencing RM are affected by DNA fragmentation abnormalities.

MATERIALS AND METHODS

In this retrospective study, between 2008 and 2013, couples with a history of recurrent miscarriage (≥3 first trimester miscarriages) were investigated comprehensively for known causes (karyotype, uterine, antiphospholipid syndrome, thrombophilia) and also by semen analysis, including DNA fragmentation [sperm chromatin structure analysis (SCSA)]. Statistical analysis was performed on SPSS software with significance taken as P < 0.05.

RESULTS

There were 108 couples with a median sperm DNA fragmentation index (DFI) of 9.50%. Normal levels were found in 70.5% of men (DFI < 15%), 23% had high levels (DFI 15-30%), and 6.5% had very high levels (DFI > 30%). Couples with otherwise unexplained recurrent miscarriage had significantly higher DFI than those with other causes identified on routine screening (P = 0.012).

CONCLUSIONS

In couples experiencing RM, 30% (32/108) of men had sperm with high levels of DNA fragmentation (DFI > 15%). This may be a contributing factor to the clinical syndrome of RM, and future clinical trials of therapies for these couples are warranted.

The sperm quality and clinical outcomes were not affected by sY152 deletion in Y chromosome for oligozoospermia or azoospermia men after ICSI treatment

Azoospermia factor (AZF) microdeletion plays a key role in the genetic etiology of male infertility. The relationship between sY152 deletion in the AZFc region and clinical outcomes is still unclear. This study was to determine the effects of sY152 deletion on the sperm parameters and clinical outcomes of non-obstructive azoospermia or oligozoospermia men after intracytoplasmic sperm injection (ICSI) treatment. A total of 61 infertile men with AZFc microdeletion of the Y chromosome from January 2008 to December 2012 were recruited in the present study. They were divided into two groups, the sY152 group (n=12) and the AZFc group (n=49), based upon whether they have deleted single sY152 marker or all AZFc markers. Fifty azoospermia or oligozoospermia patients without Y chromosome microdeletion were included as the control group. The sperm quality and clinical data were compared among the three groups. Retrospective cohort-control study was performed. The sperm concentration and motility in sY152 group were better than AZFc group (P<0.05), and were comparable to the control group (P>0.05); the morphology, seminal zinc, seminal fructose and seminal carnitine were similar among the three groups (P>0.05). Patients in both sY152 and AZFc groups had lower fertilization rates (68.40% and 70.63%, respectively) than those in the control group (74.91%), and the differences were statistically significant (P<0.05). No significant differences were found in terms of MII oocyte, high-grade embryo rate, 2PN zygote, number of available embryos and transferred embryos, clinical pregnancy rate, implantation rate, miscarriage rate, multiple pregnancy rate, delivery rate, preterm rate and the male/female ratio among the three groups (P>0.05). Single sY152 deletion might cause a lower fertilization rate, but no adverse effects on sperm quality and clinical outcomes were found. Our study may provide more information for consultation in these patients.

Decrease in fertilization and cleavage rates, but not in clinical outcomes for infertile men with AZF microdeletion of the Y chromosome

This study aimed to explore whether the presence of a Y chromosome azoospermia factor (AZF) microdeletion confers any adverse effect on embryonic development and clinical outcomes after intracytoplasmic sperm injection (ICSI) treatment. Fifty-seven patients with AZF microdeletion were included in the present study and 114 oligozoospermia and azoospermia patients without AZF microdeletion were recruited as controls. Both AZF and control groups were further divided into subgroups based upon the methods of semen collection: the AZF-testicular sperm extraction subgroup (AZF-TESE, n = 14), the AZF-ejaculation subgroup (AZF-EJA, n = 43), the control-TESE subgroup (n = 28) and the control-EJA subgroup (n = 86). Clinical data were analyzed in the two groups and four subgroups respectively. A retrospective case-control study was performed. A significantly lower fertilization rate (69.27 versus 75.70%, P = 0.000) and cleavage rate (89.55 versus 94.39%, P = 0.000) was found in AZF group compared with the control group. Furthermore, in AZF-TESE subgroup, the fertilization rate (67.54 versus 74.25%, P = 0.037) and cleavage rate (88.96 versus 94.79%, P = 0.022) were significantly lower than in the control-TESE subgroup; similarly, the fertilization rate (69.85 versus 75.85%, P = 0.004) and cleavage rate (89.36 versus 94.26%, P = 0.002) in AZF-EJA subgroup were significantly lower than in the control-EJA subgroup; however, the fertilization rate and cleavage rate in AZF-TESE (control-TESE) subgroup was similar to that in the AZF-EJA (control-EJA) subgroup. The other clinical outcomes were comparable between four subgroups (P > 0.05). Therefore, sperm from patients with AZF microdeletion, obtained either by ejaculation or TESE, may have lower fertilization and cleavage rates, but seem to have comparable clinical outcomes to those from patients without AZF microdeletion.

Sperm selection: effect on sperm DNA quality

The selection of spermatozoa without DNA fragmentation and chromosomal diseases prior to assisted reproductive techniques helps to optimize the outcome of the treatment; in particular, sperm selection prior to in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) is crucial. In fact, although ICSI has been successfully and safely applied worldwide for almost 20 years, at the present time we have no real knowledge regarding the hypothetical long-term side effects on ICSI adults, given the increased likelihood of spermatozoa with defective nuclear content fertilizing oocytes.In the case of DNA damage, the basal sperm DNA fragmentation rate can be significantly reduced by some sperm processing procedures that improve the percentage of spermatozoa with normal chromatin structure by filtering out DNA-damaged spermatozoa. After this first step, new advances in micromanipulation can be performed to choose the "ideal" mature spermatozoa for ICSI, reducing potential damage to the gametes. In fact, it is possible to prevent fertilization by DNA-damaged and chromosomal-unbalanced spermatozoa by selecting ICSI sperm by maturation markers such as hyaluronic acid or other zona pellucida receptors. Furthermore, novel noninvasive imaging techniques can be valid tools for helping in the morphological selection of ICSI spermatozoa.

Paternal factors in spontaneous first trimester miscarriage

Objectives: To determine whether paternal factors i.e., age, tobacco use and genital tract infection increase the risk for spontaneous first trimester miscarriage.

Methodology: This case control study was conducted in the Department of Obstetrics & Gynaecology, Unit V / IV, Dow Medical College & Lyari General Hospital, Dow University of Health Sciences, Karachi, Pakistan. Duration of study was two and half years, from Nov, 2007 to Apr, 2010. Inclusion criteria were pregnant women with age 20 – 35 years irrespective of parity. Exclusion criteria were known medical illness in either partner, induced abortion and recurrent miscarriages. Studied paternal factors were age, tobacco use and genital tract infection. Data was computed using SPSS version 16. Significance of paternal factors was determined by Logistic Regression Analysis.

Results: Total cases studied were 200, while there were 400 controls. Mean maternal age was 27.6±4.9 years in cases and 26.5±4.5 years in controls. Mean paternal age was 35.5±6.2 years in cases and 32.3±5.4 years in controls. Paternal age was >35 years in 54.5% cases and 16.8% controls. Spearman Bivariate correlation revealed paternal age > 35 years (p=0.000) and genital tract infection (p=0.043) as significant factors. Only paternal age >35 years (p=0.000) remained significant in Final Model after entering into logistic regression.

Conclusion: Paternal age beyond 35 years was found to be significantly related to first trimester spontaneous miscarriages.

Ubiquitin-specific protease (USP26) gene alterations associated with male infertility and recurrent pregnancy loss (RPL) in Iranian infertile patients

BACKGROUND AND PURPOSE

The human X chromosome is enriched with testis-specific genes that may be crucial for male fertility. Mutations in USP26 gene have been proposed to be associated with male infertility. Moreover, the importance of the ubiquitin pathway during different stages of mammalian fertilization and even embryo development has been addressed. Some mutations and haplotypes on this gene have been proposed to be associated with male infertility. In this study, five different mutations on USP26 were investigated: 1737 G > A, 1090 C > T, 370-371ins ACA, 494 T > C and 1423 C > T.

METHODS

The study included 166 infertile men with non-obstructive azoospermia, 72 male partners of couples who had previously experienced ≥3 clinical first trimester spontaneous abortions and 60 fertile men. Besides family history of reproduction, hormonal evaluation and semen analysis were performed. DNA was extracted from blood samples. PCR-SSCP, PCR-RFLP and PCR Product Cloning methods were used and resumed by sequencing to insure about the mutations. Moreover, USP26 gene expression was studied by Real-Time PCR after RNA extraction followed by cDNA synthesis from 24 testis biopsies in obstructive and non-obstructive azoospermia patients.

RESULTS

The results indicate that there is a haplotype between three observed mutations in Iranian population include: 370-371insACA, 1423C > T and 494 T > C. This haplotype was seen in control group as well. Surprisingly, total frequency of mutations in men with history of idiopathic RPL and azoospermic cases were significantly higher than that of in control groups (p < 0.05). Serum testosterone concentrations and testicular volume did not differ in the mutation positive group compared with the non-mutation group. About the USP26 gene expression, there is a significant difference between the expression levels of obstructive azoospermia, complete maturation arrest samples and SCO samples (P < 0.05).

CONCLUSIONS

According to our results, the USP26 gene may play an important role in male reproduction. The alterations of this gene may be involved in male infertility and RPL in Iranian population and may negatively affect testicular function.

Y chromosome AZFc microdeletion may not affect the outcomes of ICSI for infertile males with fresh ejaculated sperm

PURPOSE

To explore whether the presence of a Y chromosome AZFc microdeletion confers any adverse effect on the outcomes of intracytoplasmic sperm injection (ICSI) with fresh ejaculated sperm.

METHODS

A total of 143 oligozoospermia patients with Y chromosome AZFc microdeletion in ICSI cycles in a five-year period were studied. Infertile men with normal Y chromosome in ICSI at the same time-frame were used as controls matched to the study group for age of female, female's body mass index, male's age, infertility duration and number of oocytes retrieved. Retrospective case-control study was used.

RESULTS

There were no significant differences between groups in clinical outcomes of endometrial thickness, transferred embryos, good embryo rates, implantation rates, biochemical pregnancy rates, clinical pregnancy rates, ectopic pregnancy rates, miscarriage rates, preterm birth rates, the ratio of male and female babies, newborn body height, newborn weight, low birth weight and birth defects (P > 0.05). Patients with Y chromosome AZFc microdeletion had a lower fertilization rate (61.8 % vs. 67.8 %, P < 0.05) and higher cleaved embryo rate (94.0 % vs. 88.1 %, P < 0.05).

CONCLUSIONS

ICSI clinical outcomes for oligozoospermic patients with Y chromosome AZFc microdeletion are basically comparable to that of infertile patients with normal Y chromosomes. The results of ICSI were not affected by the AZFc deletion. Preimplantation genetic diagnosis (PGD) before ICSI for Y chromosome AZFc microdeletion may not be a justifiable regular procedure if the couples didn't care the vertical transmission of Y chromosome deletion.

The utility of sperm DNA damage assay using toluidine blue and aniline blue staining in routine semen analysis

OBJECTIVE

The aim of the present study was to examine the relationship among male age, strict morphology, and sperm chromatin structure and condensation.

METHODS

Sperm samples from a total of 100 men underwent semen analysis, and sperm chromatin structure and condensation were assessed with toluidine blue (TB) and aniline blue (AB) tests.

RESULTS

Prevalence of strict morphology of less than 4%, and abnormal sperm chromatin structure and condensation did not show any statistically significant differences according to male age (p=0.605, p=0.235, and p=0.080). No significant correlation was demonstrated among age of male partners, strict morphology, and abnormal sperm chromatin structure using TB and AB tests. However, abnormal sperm chromatin condensation was positively associated with sperm chromatin structure (r=0.594, p=0.000) and showed negative correlation with strict morphology (r=-0.219, p=0.029).

CONCLUSION

The tests for sperm chromatin condensation showed a significant association with strict morphology. Further study is needed to elucidate the relationship between clinical outcome and sperm chromatin tests.

Development of a specific method to evaluate 8-hydroxy,2-deoxyguanosine in sperm nuclei: relationship with semen quality in a cohort of 94 subjects

Oxidative stress (OS) is involved in many disoders including male infertility. Human spermatozoa are very sensitive targets of reactive oxygen species (ROS) and most sperm functions are impaired in the case of OS. In addition unbalanced production of ROS is considered one of the most important causes of sperm DNA fragmentation, a semen trait of infertile men. The relationship between oxidative damage and semen quality is partially controversial, probably due to the different methods and/or targets used to reveal the OS. In this study, by fluorescence microscopy and flow cytometry, we compared two methods to reveal 8-hydroxy,2-deoxyguanosine (8-OHdG), the hallmark of oxidative DNA damage: an immunofluorescence method and the commercial OxyDNA kit. We found that although both methods localized the labelling in sperm nuclei they yielded different measures, and only with the immunofluorescence method was the labelling specific for sperm 8-OHdG. The immunofluorescence method, coupled to flow cytometry, was thus selected to analyse the 8-OHdG content in semen samples from 94 subfertile patients and to investigate the relationship with semen quality. We found that the percentages of spermatozoa with 8-OHdG (mean±s.d., 11.4±6.9%) were related to sperm count (Pearson's correlation coefficient (r)=−0.27, P=0.04 (ANOVA and student's t-test)), motility (progressive: r=−0.22, P=0.04; non-progressive: r=0.25, P=0.01), and normal morphology (r=−0.27, P=0.01). In conclusion, we demonstrate that immunofluorescence/flow cytometry is a reliable and specific method to detect 8-OHdG at single-cell level and show that oxidative damage only partially overlaps poor semen quality, suggesting that it could provide additional information on male fertility with respect to routine semen analysis.

Y chromosome azoospermia factor region microdeletions are not associated with idiopathic recurrent spontaneous abortion in a Slovenian population: association study and literature review

OBJECTIVE

To investigate the potential association of Y chromosome microdeletions with idiopathic recurrent spontaneous abortion (IRSA) in a Slovenian population and compare our results with those of previously published studies in different populations, with the intention of clarifying the potential impact of Y chromosome microdeletions on IRSA.

DESIGN

Case-control and association study.

SETTING

Departments of gynecology and obstetrics and university-based research laboratory.

PATIENT(S)

Male partners of 148 couples with at least three spontaneous pregnancy losses of unknown etiology, and 148 fertile men.

INTERVENTION(S)

Multiplex polymerase chain reactions.

MAIN OUTCOME MEASURE(S)

Azoospermia factor (AZF) regions were tested for Y chromosome microdeletions according to European Academy of Andrology/European Molecular Genetics Quality Network guidelines. The PubMed database was searched to retrieve articles linking Y chromosome microdeletions and susceptibility to IRSA.

RESULT(S)

None of the IRSA or control men had microdeletions in the AZFa, AZFb, or AZFc regions. A total of nine previous studies examined the relationship between Y chromosome microdeletions and IRSA, yielding contradictory results, which we discuss in detail.

CONCLUSION(S)

On the basis of our comparisons, it is unlikely that Y chromosome microdeletions contribute to IRSA and are therefore currently not recommended for the routine evaluation of IRSA couples.

Sperm DNA damage: how relevant is it clinically?

PURPOSE OF REVIEW

The true impact of the current sperm DNA fragmentation testing needs further scrutiny to assess whether clinically meaningful information is conveyed.

RECENT FINDINGS

Various studies have suggested different or no threshold values with assorted tests for the percentage of DNA fragmentation in the ejaculated sperm above which natural conception, fertilization or embryo development and/or clinical pregnancy rates are compromised. Current DNA fragmentation assessment methods provide very little specific information on the nature and severity of the DNA damage detected. Although sperm DNA fragmentation is associated with lower pregnancy rates through natural conception or intrauterine insemination, it does not seem to affect intracytoplasmic sperm injection outcome. Although animal studies demonstrated adverse reproductive effects of sperm DNA fragmentation, any conclusive evidence in humans is yet to be demonstrated. It is not clear whether interventions aimed at enrichment of sperm with decreased DNA fragmentation are effective in preventing the potential adverse effects of sperm DNA fragmentation in humans. Major concern about the use of sperm DNA integrity tests as prognostic parameters is that the direct evaluation of DNA fragmentation in individual sperm fertilizing the oocyte is not possible.

SUMMARY

The lack of consensus in defining a clinically relevant standard DNA fragmentation test with a meaningful cut-off level brings challenges in implementing the routine use of sperm DNA integrity assessment in daily practice.

Double stranded sperm DNA breaks, measured by Comet assay, are associated with unexplained recurrent miscarriage in couples without a female factor

It is known that sperm samples from recurrent pregnancy loss (RPL) couples have an increase in their sperm DNA fragmentation (SDF), but no studies have been performed in order to identify differences between single stranded SDF (ssSDF) and double stranded SDF (dsSDF) in these patients. This could be relevant because the type of DNA damage could have different effects. Semen samples were classified attending their clinical status: 25 fertile donors and 20 RPL patients with at least two unexplained first trimester miscarriages. SDF was analysed using alkaline and neutral Comet assay, SCD test and pulsed-field gel electrophoresis (PFGE), and ROC analysis including data from 105 more infertile patients (n = 150) was performed to establish predictive threshold values. SDF for alkaline and neutral Comet, and the SCD test was analysed in these categories of individuals. Data revealed the presence of two subgroups within fertile donors. The values obtained were 21.10±9.13, 23.35±10.45 and 12.31±4.31, respectively, for fertile donors with low values for both ssSDF and dsSDF; 27.86±12.64, 80.69±12.67 and 12.43±5.22, for fertile donors with low ssSDF and high dsSDF; and 33.61±15.50, 84.64±11.28 and 19.28±6.05, for unexplained RPL patients, also showing a low ssSDF and high dsSDF profile. This latter profile was seen in 85% of unexplained RPL and 33% of fertile donors, suggesting that it may be associated to a male risk factor for undergoing RPL. ROC analysis regarding recurrent miscarriage set the cut-off value at 77.50% of dsDNA SDF. PFGE for low ssSDF and high dsSDF profile samples and positive controls treated with DNase, to induce dsDNA breaks, showed a more intense band of about 48 kb, which fits the toroid model of DNA compaction in sperm, pointing out that some nuclease activity may be affecting their sperm DNA in RPL patients. This work identifies a very specific SDF profile related to the paternal risk of having RPL.

The effect of sperm DNA fragmentation on miscarriage rates: a systematic review and meta-analysis

STUDY QUESTION

Is there an association between high levels of sperm DNA damage and miscarriage?

SUMMARY ANSWER

Miscarriage rates are positively correlated with sperm DNA damage levels.

WHAT IS KNOWN ALREADY

Most ejaculates contain a subpopulation of sperm with DNA damage, also referred to as DNA fragmentation, in the form of double or single-strand breaks which have been induced in the DNA prior to or following ejaculation. This DNA damage may be particularly elevated in some subfertile men, hence several studies have examined the link between sperm DNA damage levels and conception and miscarriage rates.

STUDY DESIGN, SIZE, DURATION

A systematic review and meta-analysis of studies which examined the effect of sperm DNA damage on miscarriage rates was performed. Searches were conducted on MEDLINE, EMBASE and the Cochrane Library without any language restrictions from database inception to January 2012.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used the terms 'DNA damage' or 'DNA fragmentation' combined with 'miscarriage', 'abortion' or 'pregnancy' to generate a set of relevant citations. Data extraction was performed by two reviewers. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analysis of relative risks of miscarriage was performed with a random effects model. Subgroup analyses were performed by the type of DNA damage test, whether the sperm examined were prepared or from raw semen and for pregnancies resulting from IVF or ICSI treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified 16 cohort studies (2969 couples), 14 of which were prospective. Eight studies used acridine orange-based assays, six the TUNEL assay and two the COMET assay. Meta-analysis showed a significant increase in miscarriage in patients with high DNA damage compared with those with low DNA damage [risk ratio (RR) = 2.16 (1.54, 3.03), P < 0.00001)]. A subgroup analysis showed that the miscarriage association is strongest for the TUNEL assay (RR = 3.94 (2.45, 6.32), P < 0.00001).

LIMITATIONS, REASONS FOR CAUTION

There is some variation in study characteristics, including the use of different assays and different thresholds for DNA damage and the definition of pregnancy loss.

WIDER IMPLICATIONS OF THE FINDINGS

The use of methods which select sperm without DNA damage for use in assisted conception treatment may reduce the risk of miscarriage. This finding indicates that assays detecting DNA damage could be considered in those suffering from recurrent pregnancy loss. Further research is necessary to study the mechanisms of DNA damage and the potential therapeutic effects of antioxidant therapy.

STUDY FUNDING/COMPETING INTEREST(S)

None.

Predictive value of DNA integrity analysis in idiopathic recurrent pregnancy loss following spontaneous conception

PURPOSE

Standard semen parameters are poor predictors of fertility potential. To date, apart from, paternal karyotyping sperm factors are not evaluated in recurrent pregnancy loss (RPL), only recent studies have emphasized the role of sperm factors in early embryonic development as sperm transcribes genes critical for early embryonic development. Sperm DNA integrity is useful diagnostic and prognostic marker and has clinical implications in idiopathic recurrent pregnancy loss (iRPL) following spontaneous conception. The aim of this study was to assess DNA integrity in cases experiencing iRPL following spontaneous conception.

METHODS

Semen samples from 45 patients and 20 controls were analyzed as per WHO 1999 guidelines and sperm chromatin structure assay (SCSA) was used to measure DNA fragmentation index (DFI).

RESULTS

By applying receiver operating curve (ROC) analysis, sperm DFI of approximately 26 % was found in male partner of couples experiencing iRPL.

CONCLUSIONS

Our data indicate that sperm from men with a history of iRPL have a higher percentage of DNA damage as compared to control group, and this can explain pregnancy loss in these patients. Men with higher DFI are infertile whereas men with lower DFI (26 %) are able to conceive but experience recurrent pregnancy loss. Thus it is important to evaluate sperm DFI in couples experiencing iRPL to understand exact aetiology of RPL and determine prognosis and management.

Sperm DNA fragmentation index does not correlate with the sperm or embryo aneuploidy rate in recurrent miscarriage or implantation failure patients

BACKGROUND

The aneuploidy rate is higher in poor-quality sperm samples, which also have higher DNA fragmentation index values. The aim of this study was to assess the relationship between sperm DNA fragmentation in samples from infertile men belonging to couples with recurrent miscarriage or implantation failure and the aneuploidy rate in spermatozoa as well as in embryos from patients.

METHODS

This prospective study evaluated DNA damage and the aneuploidy rate in fresh and processed (density gradient centrifugation) ejaculated sperm as well as the aneuploidy rate in biopsied embryos from fertility cycles. Fluorescence in situ hybridization was used for the aneuploidy analysis. Results were compared using linear regression and analysis of variance.

RESULTS

A total of 154 embryos were evaluated from 38 patients undergoing PGD cycles; 35.2% of the embryos were chromosomally normal. Analysis of the same sperm samples showed an increased DNA fragmentation after sperm preparation in 76% of the patients. There was no correlation between DNA fragmentation and the aneuploidy rate in embryos or in fresh or processed sperm samples.

CONCLUSIONS

Sperm DNA fragmentation is not related to chromosomal anomalies in embryos from patients with recurrent miscarriage or implantation failure. However, we cannot rule out the possibility that a relationship between DNA fragmentation and aneuploidy exists for other causes of infertility. Furthermore, the different methods used to evaluate DNA fragmentation may produce different results.

Y chromosome microdeletions in Mexican males of couples with idiopathic recurrent pregnancy loss

AIM

To analyze the presence of Y chromosome microdeletions in males of Mexican couples with idiopathic recurrent pregnancy losses (RPL).

METHODS

Seventy-one males from couples with RPL and 66 fertile males as controls were studied. DNA was isolated from peripheral lymphocytes and used to run multiplex polymerase chain reactions. Regions AZFa (sY84, sY86), AZFb (sY127, sY134) and AZFc (sY254, sY255) of the Y chromosome were analyzed according to valid guidelines recommended by the European Academy of Andrology and the European Molecular Genetics Quality Network. Also, the sequence tagged sites (STSs): DYS262 (sY67), DYS220 (sY129), DYF85S1 (sY150), DYF86S1 (sY152) and DYF87S1 (sY153) were included in order to analyze STSs previously reported as deleted. A power analysis to support our simple size was performed.

RESULTS

Results show an absence of Y chromosome microdeletions in males of couples with RPL and controls with an acceptable statistical power.

CONCLUSION

The study did not show an association of recurrent pregnancy loss and Y chromosome microdeletions in Mexican male partners. Based on the results, the study of Y chromosome microdeletions in couples with RPL is not considered clinically relevant.

Sperm DNA Fragmentation: Origin and Impact on Human Reproduction

Sperm DNA can be damaged due to a multitude of different noxae, which include disease, and occupational and environmental factors. Depending on the magnitude of the damage, such lesions may be repaired by the oocyte or the embryo. If this is not possible, a permanent damage can be manifested leading to mutations of the male genome. In cases where the oocyte or the embryo does not counter these damages to the male genome in terms of repair or an early abortion, sperm DNA damage and fragmentation can be a cause of numerous diseases including childhood cancer.

Semen parameters and sperm DNA fragmentation as causes of recurrent pregnancy loss

OBJECTIVES

To evaluate and compare standard sperm parameters, and sperm DNA fragmentation in seminal ejaculates from men whose partners had a history of recurrent pregnancy loss (RPL) and in a control group of men who had recently established their fertility.

METHODS

Semen samples from 31 patients with a history of recurrent pregnancy loss and 20 men with proven fertility were analyzed according to World Health Organization guidelines. Sperm DNA fragmentation was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay.

RESULTS

When sperm quality of the control group was compared with that of the RPL group, a significant difference was observed in sperm motility, but not in other parameters. The mean number of sperm cells with fragmented DNA was significantly increased in the RPL group (32.22 ± 6.14%) compared with control donors (10.20 ± 2.1%).

CONCLUSIONS

Our data indicate that sperm from men with a history of RPL have a higher incidence of DNA damage and poor motility than sperm from a control group, and this can explain in part the pregnancy loss in these patients.

Cytogenetic, Y chromosome microdeletion, sperm chromatin and oxidative stress analysis in male partners of couples experiencing recurrent spontaneous abortions

PURPOSE

Etiology in majority of couples experiencing recurrent spontaneous abortions (RSA) is still unknown. The aim of the study was to find the role of cytogenetic abnormalities, Y chromosome microdeletion, oxidative stress (OS) and sperm DNA fragmentation in male partners of couples experiencing RSA.

METHODS

Forty-eight couples with history of RSA and 20 fertile controls were included in the study. The study subjects were divided into male partners of RSA couples with abnormal sperm parameters (SA) (N = 16), male partners of RSA couples with normal sperm parameters (NS) (N = 32) and age-matched fertile controls with normal sperm parameters (FC) (N = 20).

RESULTS

One of 48 men (2%) showed 46, XY (1qh-) chromosomal complement. None of the cases including FC showed deletion in any of the 3 AZF loci on Y chromosome long arm. Sperm count was found be significantly lower in SA cases as compared to group NS cases (P < 0.0001) and FC (P < 0.005). Sperm forward motility was found to be significantly (P < 0.05) lower in SA cases as compared to NS and FC. Male partners of RSA couples with abnormal sperm parameters had higher reactive oxygen species (ROS) levels (P < 0.005) and sperm DNA damage (P < 0.0001), however, in male partners of RSA couples with normal sperm parameters had only increased (P < 0.0001) sperm DNA damage.

CONCLUSION

Other than chromosomal anomalies, sperm DNA fragmentation and seminal OS may be the underlying pathology in RSA, thus screening for seminal ROS levels and DNA fragmentation has diagnostic and prognostic capabilities.