Black Father's Influence on Adverse Pregnancy Outcomes in the United States: A Narrative Synthesis of Literature

Few studies have investigated paternal characteristics in relationship with adverse pregnancy outcomes, and results are inconsistent. The purpose of this study was to review studies examining associations between characteristics of Black fathers and adverse pregnancy outcomes in the United States. A systematic narrative synthesis was conducted of research studies examining paternal characteristics of Black fathers in association with adverse pregnancy outcomes: preterm birth, hypertensive disorders of pregnancy, gestational diabetes, spontaneous abortion, and maternal mortality. Seven databases (Academic Search Premier, CINHAL, CENTRAL, ClinicalTrials.gov, Embase, PubMed, and Web of Science) were searched for original research articles from inception to February 2023. Articles were excluded if they (a) were in a language other than English, (b) did not describe original research, (c) included a geographic region outside of the United States, (d) did not include adverse maternal outcomes as a study outcome, (e) did not describe race of fathers in the study sample, and (f) did not describe a paternal characteristic of Black fathers. The search resulted in 210 articles. Six studies were included in the final review; five studies examined associations between paternal characteristics of Black fathers and preterm birth, finding significantly increased odds of preterm birth among births with Black fathers. Among births with non-Hispanic Black paternity, the odds of hypertensive disorders of pregnancy were reduced or not significantly associated. Researchers should continue to explore paternal factors that influence pregnancy outcomes in racial/ethnic-specific models to identify optimal intervention strategies to improve disparities in maternal and child health outcomes.

Investigating the impact of paternal age, paternal heat stress, and estimation of non-genetic paternal variance on dairy cow phenotype

BACKGROUND

Linear models that are commonly used to predict breeding values in livestock species consider paternal influence solely as a genetic effect. However, emerging evidence in several species suggests the potential effect of non-genetic semen-mediated paternal effects on offspring phenotype. This study contributes to such research by analyzing the extent of non-genetic paternal effects on the performance of Holstein, Montbéliarde, and Normande dairy cows. Insemination data, including semen Batch Identifier (BI, a combination of bull identification and collection date), was associated with various traits measured in cows born from the insemination. These traits encompassed stature, milk production (milk, fat, and protein yields), udder health (somatic cell score and clinical mastitis), and female fertility (conception rates of heifers and cows). We estimated (1) the effects of age at collection and heat stress during spermatogenesis, and (2) the variance components associated with BI or Weekly aggregated BI (WBI).

RESULTS

Overall, the non-genetic paternal effect estimates were small and of limited biological importance. However, while heat stress during spermatogenesis did not show significant associations with any of the traits studied in daughters, we observed significant effects of bull age at semen collection on the udder health of daughters. Indeed, cows born from bulls collected after 1500 days of age had higher somatic cell scores compared to those born from bulls collected at a younger age (less than 400 days old) in both Holstein and Normande breeds (+ 3% and + 5% of the phenotypic mean, respectively). In addition, across all breeds and traits analyzed, the estimates of non-genetic paternal variance were consistently low, representing on average 0.13% and 0.09% of the phenotypic variance for BI and WBI, respectively (ranging from 0 to 0.7%). These estimates did not significantly differ from zero, except for milk production traits (milk, fat, and protein yields) in the Holstein breed and protein yield in the Montbéliarde breed when WBI was considered.

CONCLUSIONS

Our findings indicate that non-genetic paternal information transmitted through semen does not substantially influence the offspring phenotype in dairy cattle breeds for routinely measured traits. This lack of substantial impact may be attributed to limited transmission or minimal exposure of elite bulls to adverse conditions.

Factors influencing natural fecundity in fertile couples: a survey of puerperae and their partners

RESEARCH QUESTION

What is the fecundity rate among fertile couples, and which factors influence it?

DESIGN

Retrospective study of all puerperae attending Cruces University Hospital Human Reproduction Unit over 9 months. An anonymous questionnaire was circulated to all patients, and 2510 valid completed questionnaires were collected. The main inclusion criterion was natural conception resulting in delivery. Pregnancies resulting from ART and contraceptive method failure were excluded. Investigated parameters were time to pregnancy, age and smoking (in women and men), previous pregnancies and intercourse frequency. A mathematical formula was developed to predict the per-month fecundity rate (PMFR).

RESULTS

The cumulative fecundity rate was 29.08%, 54.26%, 68.61%, 89.88%, 96.95% and 98.63% (at 1, 3, 6, 12, 24 and 36 months); between 12 and 36 months, the average PMFR ranged from 8.53-7.48%. Only 1.68% of pregnancies occurred between 24 and 36 months, and only 1.37% thereafter. The best fecundity markers were obtained in the group who had sexual intercourse seven to eight times a week. Women and men younger than 25 years had lower fecundity markers than those aged between 25 and 40 years.

CONCLUSIONS

Fertile couples have a non-negligible per-month fecundity rate between 12 and 36 months, which should be considered when planning fertility studies. The lower fecundity rate observed in women and men aged younger than 25 years deserves more study. Coital frequencies of more than two or three times a week did not affect the fecundity rate and was better with frequencies of seven to eight times a week.

Advanced Paternal Age in Focus: Unraveling Its Influence on Assisted Reproductive Technology Outcomes

As global demographics shift toward increasing paternal age, the realm of assisted reproductive technologies (ARTs), particularly in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), faces new challenges and opportunities. This study provides a comprehensive exploration of the implications of advanced paternal age on ART outcomes. Background research highlights the social, cultural, and economic factors driving men toward later fatherhood, with a focus on the impact of delayed paternity on reproductive outcomes. Methods involve a thorough review of existing literature, centering on changes in testicular function, semen quality, and genetic and epigenetic shifts associated with advancing age. Study results point to intricate associations between the father's age and ART outcomes, with older age being linked to diminished semen quality, potential genetic risks, and varied impacts on embryo quality, implantation rates, and birth outcomes. The conclusions drawn from the current study suggest that while advanced paternal age presents certain risks and challenges, understanding and mitigating these through strategies such as sperm cryopreservation, lifestyle modifications, and preimplantation genetic testing can optimize ART outcomes. Future research directions are identified to further comprehend the epigenetic mechanisms and long-term effects of the older father on offspring health. This study underscores the need for a comprehensive approach in navigating the intricacies of delayed fatherhood within the context of ART, aiming for the best possible outcomes for couples and their children.

Paternal age and first trimester placental size and growth: The Rotterdam Periconceptional Cohort

INTRODUCTION

Despite a noticeable trend of delayed fatherhood, less is known about the impact of paternal age on the paternally programmed placenta. We hypothesize that paternal aging affects seminal quality and as such induces ageing-related epigenetic alterations that influence placental growth. Our main aim is to investigate associations between paternal age and first trimester (vascular) placental growth trajectories.

METHODS

Pregnant women were enrolled before 10 weeks of gestation in the Rotterdam Periconceptional Cohort (Predict study). Placental volumes (PV) and utero-placental vascular volumes (uPVV) were measured at 7, 9, and 11 weeks gestation. Associations between paternal age and PV and uPVV were investigated using linear mixed models and the maximum likelihood ratio test to test non-linear relationships. We adjusted for gestational age, fetal sex, parental smoking and maternal age, BMI, education and parity, and stratified for conception mode.

RESULTS

From 808 pregnancies we obtained 1313 PV and from 183 pregnancies 345 uPVV measurements. We show no associations between paternal age and PV (p = 0.934) and uPVV (p = 0.489) in our total population or in pregnancies conceived naturally (PV p = 0.166; uPVV p = 0.446) and after IVF/ICSI (PV p = 0.909; uPVV p = 0.749). For example, PV was 0.9% smaller (95% CI -5.7%-7.1%) in fathers aged 40 compared to 30 years old at 9 weeks gestation in the total study population.

DISCUSSION

We are not demonstrating a significant impact of paternal age on first trimester placental growth in a tertiary care population. Given the trend of increasing paternal age, our study should be repeated in the general population.

Parental overproduction allows siblicidal bird to adjust brood size to climate-driven prey variation

Parental overproduction is hypothesized to hedge against uncertainty over food availability and stochastic death of offspring and to improve brood fitness. Understanding the evolution of overproduction requires quantifying its benefits to parents across a wide range of ecological conditions, which has rarely been done. Using a multiple hypotheses approach and 30 years of data, we evaluated the benefits of overproduction in the Blue-footed booby, a seabird that lays up to three eggs asynchronously, resulting in an aggressive brood hierarchy that facilitates the death of last-hatched chicks under low food abundance. Results support the resource-tracking hypothesis, as low prey abundance (estimated from sea surface temperature and chlorophyll-a concentration) led to rapid brood reduction. The insurance hypothesis was supported in broods of three, where last-hatched chicks' survival increased after a sibling's death. Conversely, in broods of two, results suggested that parents abandoned last-hatched chicks following first-hatched chicks' deaths. No direct evidence supported the facilitation hypothesis: the presence of a last-hatched chick during development did not enhance its sibling's fitness in the short or long term. The value of last-hatched offspring to parents, as "extra" or "insurance" varied with indices of food abundance, brood size, and parental age. Ninety percent of overproduction benefits came from enabling parents to capitalize on favorable conditions by fledging additional offspring. Our study provides insight into the forces driving overproduction, explaining the adaptiveness of this apparently wasteful behavior and allowing us to better predict how overproduction's benefits might be modified by ocean warming.

Change in the perceived reproductive age window and delayed fertility in Europe

While extensive literature documents the massive fertility delay of recent decades, knowledge about whether and how attitudes towards the timing of births have changed in Europe remains limited. Using data from two rounds of the European Social Survey, we investigate these changes and their association with macro-level fertility indicators in 21 countries. Between 2006-07 and 2018-19, societal consensus regarding the existence of optimal childbearing ages remained strong and became more in favour of later parenthood. Decomposition analyses show that these shifts were driven only partially by changes in population composition, supporting the idea that a general attitudinal change in favour of later childbearing is underway. We also find a trend towards gender convergence in upper age limits driven by the increasing social recognition of an age deadline for men's childbearing. Although shifts in perceived reproductive age windows occurred during periods of birth postponement, they corresponded only loosely to country-level changes in fertility.

Frequency, morbidity and equity - the case for increased research on male fertility

Currently, most men with infertility cannot be given an aetiology, which reflects a lack of knowledge around gamete production and how it is affected by genetics and the environment. A failure to recognize the burden of male infertility and its potential as a biomarker for systemic illness exists. The absence of such knowledge results in patients generally being treated as a uniform group, for whom the strategy is to bypass the causality using medically assisted reproduction (MAR) techniques. In doing so, opportunities to prevent co-morbidity are missed and the burden of MAR is shifted to the woman. To advance understanding of men's reproductive health, longitudinal and multi-national centres for data and sample collection are essential. Such programmes must enable an integrated view of the consequences of genetics, epigenetics and environmental factors on fertility and offspring health. Definition and possible amelioration of the consequences of MAR for conceived children are needed. Inherent in this statement is the necessity to promote fertility restoration and/or use the least invasive MAR strategy available. To achieve this aim, protocols must be rigorously tested and the move towards personalized medicine encouraged. Equally, education of the public, governments and clinicians on the frequency and consequences of infertility is needed. Health options, including male contraceptives, must be expanded, and the opportunities encompassed in such investment understood. The pressing questions related to male reproductive health, spanning the spectrum of andrology are identified in the Expert Recommendation.

Paternal age and perinatal outcomes: an observational study

OBJECTIVES

The study's primary aim was to examine the relationship between paternal age and perinatal outcomes.

METHODS

This study used data from two hospital birth registries to examine the association between paternal age and adverse perinatal outcomes. The sample included all live singleton births between 2010 and 2022. The primary exposure was paternal age, and the following perinatal outcomes were considered: mode of conception, mode of delivery, pregnancy complications, and neonatal outcomes.

RESULTS

A total of 15,232 pregnant women were considered. Maternal and paternal ages were 31.9 ± 5.3 and 36.5 ± 6.5 years, respectively. Independent of maternal, paternal age was associated with lower odds of spontaneous conceptions (OR 0.930, 95 % CI 0.968/0.993; p=0.003) and higher odds of intracytoplasmatic sperm injection (OR 1.054, 95 % CI 1.045/1.062; p=0.0001), respectively. In contrast to maternal age, paternal age decreased the odds of any (OR 0.922, 95 % CI 0.985/0.999; p=0.032) and urgent/emergent (OR 0.984, 95 % CI 0.975/0.993; p=0.0001) cesarean delivery. Paternal age did not affect the gestation length, placental or neonatal weight, blood loss during delivery, and neonatal 5th-minute Apgar score.

CONCLUSIONS

Paternal age is associated with perinatal outcomes. These findings suggest that advanced paternal age may have implications for reproductive counseling and prenatal care.

A DNA Methylation Perspective on Infertility

Infertility affects a significant number of couples worldwide and its incidence is increasing. While assisted reproductive technologies (ART) have revolutionized the treatment landscape of infertility, a significant number of couples present with an idiopathic cause for their infertility, hindering effective management. Profiling the genome and transcriptome of infertile men and women has revealed abnormal gene expression. Epigenetic modifications, which comprise dynamic processes that can transduce environmental signals into gene expression changes, may explain these findings. Indeed, aberrant DNA methylation has been widely characterized as a cause of abnormal sperm and oocyte gene expression with potentially deleterious consequences on fertilization and pregnancy outcomes. This review aims to provide a concise overview of male and female infertility through the lens of DNA methylation alterations.

Involvement of Inheritance in Determining Telomere Length beyond Environmental and Lifestyle Factors

All linear chromosomal ends have specific DNA-protein complexes called telomeres. Telomeres serve as a "molecular clock" to estimate the potential length of cell replication. Shortening of telomere length (TL) is associated with cellular senescence, aging, and various age-related diseases in humans. Here we reviewed the structure, function, and regulation of telomeres and the age-related diseases associated with telomere attrition. Among the various determinants of TL, we highlight the connection between TL and heredity to provide a new overview of genetic determinants for TL. Studies across multiple species have shown that maternal and paternal TL influence the TL of their offspring, and this may affect life span and their susceptibility to age-related diseases. Hence, we reviewed the linkage between TL and parental influences and the proposed mechanisms involved. More in-depth studies on the genetic mechanism for TL attrition are needed due to the potential application of this knowledge in human medicine to prevent premature frailty at its earliest stage, as well as promote health and longevity.

Leydig cell metabolic disorder act as a new mechanism affecting for focal spermatogenesis in Klinefelter syndrome patients: a real world cross-sectional study base on the age

Background

Klinefelter's syndrome (KS) was once considered infertile due to congenital chromosomal abnormalities, but the presence of focal spermatozoa changed this. The key to predict and promote spermatogenesis is to find targets that regulate focal spermatogenesis.

Objective

To explore the trend of fertility changes in KS patients at different ages and identify potential therapeutic targets.

Methods

Bibliometric analysis was used to collect clinical research data on KS from the Web of Science Core Collection (WoSCC) from 1992 to 2022. A cross-sectional study was conducted on 75 KS patients who underwent microscopic testicular sperm extraction (mTESE) from 2017 to 2022 in the real world. The reproductive hormones, testicular histopathology, androgen receptors, insulin-like factor 3 (INSL3) receptors and sperm recovery rate (SRR) were analyzed.

Results

Male infertility, dysplasia, Sertoli cells, Leydig cells, testosterone and spermatogenesis were the research focuses related to KS. Luteinizing hormone (LH), testosterone, and INSL3 were evaluation indicators of Leydig cell function that fluctuate with age. Testosterone and LH peaked at ages 13-19 and 30-45, while INSL3 only peaked at ages 13-19. 27 patients (27/75) recovered sperm through mTESE and experienced SRR peaks at the ages of 20, 28, 34, and 37. The SRR of fibrosis patients was 46.15%, fatty degeneration was 7.14%, and melanosis was 40.00%. The INSL3 and androgen receptors were highly expressed and roughly balanced in focal spermatogenesis.

Conclusion

Abnormal metabolism of Leydig cells led to imbalanced expression of INSL3 and androgen receptors, which might be a potential target for spermatogenesis in KS.

Third-party reproduction: a treatment that grows with societal changes

Third-party reproduction refers to the use of eggs, sperm, or embryos that have been donated by a third person (the donor) to enable individuals or couples (the intended parents) with infertility to have a child. This differs from the traditional father-mother family model with no third parties involved. Third-party reproduction is also used by couples that are unable to reproduce by traditional means, same-sex couples, and men and women without a partner. This has emerged as a treatment option with great success rates in a scene of changing family constellations. Consequently, this therapeutic alternative has become a realistic solution which has brought great satisfaction and happiness to people who otherwise would have not been able to achieve parenthood if these options were not medically and legally available.

Impact of paternal age on assisted reproductive technology outcomes and offspring health: a systematic review

BACKGROUND

The increase in paternal age and the percentage of births after assisted reproductive technologies (ART) may have consequences on offspring and society's position regarding access to ART must be questioned. Most countries recommend limiting ART to men under 60 years. What is the rationale for this threshold?

OBJECTIVE

This systematic review assesses scientific arguments to establish links between paternal age, male fertility, and offspring health.

MATERIAL AND METHODS

Using the PRISMA guidelines, this systematic review of the literature analyzed 111 articles selected after screening PubMed, ScienceDirect, and Web of Science for articles published between January 1, 1995 and December 31, 2021.

RESULTS

A strong correlation was highlighted between advanced paternal age and a decrease of some sperm parameters (semen volume and sperm motility) and infant morbidity (exponentially increased incidence of achondroplasia and Apert syndrome, and more moderately increased incidence of autism and schizophrenia). The impact of paternal age on pregnancy and fetal aneuploidy rates is more controversial. No association was found with spontaneous abortion rates.

DISCUSSION AND CONCLUSION

The scientific parameters should be explained to older parents undergoing ART. And for countries that discuss a limit on paternal age for access to ART, the debate requires consideration of social and ethical arguments.

Effect of male age on semen quality in domestic animals: potential for advanced functional and translational research?

Age and other factors like season and breed are often associated with sperm quality and fertility in domestic animals. Even though many studies assessed the relationship between the age of the male and sperm parameters, the effects have not been comprehensively evaluated. Changes in semen quality from pubertal (young) to adult and old age were identified in the bull, ram, buck, boar, dog, and stallion, respectively. The review discusses the association between male age and semen volume, the total number of spermatozoa per ejaculate, sperm concentration, motility, morphology, sperm cell function, sperm DNA integrity, oxidative stress, and antioxidant activity in these species of animals. Generally, semen characteristics improve to a certain age, which declines as the animal ages. Only a few studies evaluated the impact of advanced age or employed advanced functional sperm assessment methods to assess age-related changes in sperm quality and male fertility. Such studies in the dog or stallion, for instance, may contribute to advancing knowledge in human-assisted reproductive techniques used in patients of advanced paternal and maternal age.

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

Defects in sperm capacitation/fertilizing ability are equally prevalent across ages in men seeking fertility assistance

RESEARCH QUESTION

How do capacitation ability, measured by Cap-Score™, and traditional semen analysis measures (volume, concentration, motility) change with age in men questioning their fertility (MQF)?

DESIGN

Cap-Score and semen analysis measures were obtained from MQF (n = 2652; multicentric design: 35 reproductive endocrinologist prescribers, n = 16 clinics). Morphology was not included due to differences among clinics. A Mann-Whitney test was used to compare Cap-Scores between MQF and men with known recent paternity (n = 76). The following age groups were constructed for MQF: 20-24, 25-29, 30-34, 35-39, 40-44, 45-49 and 50+. Associations between semen analysis, Cap-Score and age groups were evaluated using mixed-model analysis of variance to identify possible influence of Cap-Score collection kit type (n = 763 collected at home; n = 1889 collected at clinics).

RESULTS

MQF had reduced capacitation ability (mean ± SE; 29.25 ± 0.15 versus 35.34 ± 0.88; P < 0.001). No change in Cap-Score (P = 0.916) or concentration (P = 0.926) was detected with age group. In contrast, both volume (P = 0.008) and % motility (P < 0.001) declined with age.

CONCLUSIONS

Men presenting because of difficulties in generating pregnancy showed equivalent reductions in capacitation ability regardless of age. In contrast, motility and volume declined with age. These data suggest that capacitation ability is a more sensitive indicator of male fertility across age groups than traditional semen analysis and should not be reserved for older men. Importantly, these data do not address whether sperm fertilizing ability declines in the general population as men age. Instead, they indicate that if men are having difficulty conceiving, no matter what their age, then defects in sperm fertilizing ability are equally likely to be the cause.

Pre-but not post-meiotic senescence affects sperm quality and reproductive success in the North African houbara bustard

Age-dependent reduction in reproductive success can arise due to multiple factors including a deterioration of reproductive physiology. Senescing males have been shown to produce ejaculates with poor sperm quality, which impinges on male reproductive success. In addition to individual age, gamete age can also affect male reproductive success. Accordingly, variance in male reproductive success can be due to pre-meiotic (referring to individual age) and post-meiotic senescence (sperm age). Here, we tested whether male senescence and sperm cell aging have additive or interactive effects on male reproductive success in a bird with a promiscuous mating system, the North African houbara bustard. To assess the effect of pre-meiotic aging, we compared male reproductive success between two age classes (3-6- and 12–16-year-old). To infer the effect of post-meiotic aging, male ejaculates were collected at three-time intervals following a common initial collection (day 1, 5, and 10). Therefore, day 1 ejaculates are supposed to contain younger sperm than day 5 and 10 ejaculates. Following controlled artificial inseminations, reproductive success was assessed using three fitness-linked traits (hatching success, chick growth rate and survival). In addition to reproductive output, we also assessed whether pre- and post-meiotic aging affected a wide range of sperm and ejaculate traits. In agreement with previous reports, we found that males in the older age class produced less sperm with poorer motility compared to young individuals. However, contrary to the prediction, we found that ejaculates collected at day 5 and 10 tended to have better sperm traits such as motility and velocity. The results on sperm traits were generally mirrored in the effect on reproductive success since young males produced offspring that grew faster and had better survival during the first month of life, and eggs fertilized by sperm collected at day 5 had the highest hatching success. In any of the models, there was evidence for interactive effects of male and sperm age. Overall, these results confirm the role of pre-meiotic aging on male reproductive success. The lack of evidence for sperm aging could come from the experimental design but might also reflect the pattern of mating frequency in a species with a lek-based mating system.

Subclinical Hypothyroidism and Sperm DNA Fragmentation: A Cross-sectional Study of 5401 Men Seeking Infertility Care

CONTEXT

Our previous study showed that paternal subclinical hypothyroidism (SCH) had a detrimental effect on the clinical outcomes of assisted reproductive technologies. However, it remains to be determined whether paternal SCH affects sperm DNA integrity.

OBJECTIVE

To investigate the association between SCH and sperm DNA fragmentation in men seeking infertility care.

METHODS

This cross-sectional study included 4983 men with euthyroidism and 418 men with SCH seeking infertility treatment in a tertiary care academic medical center between January 2017 and December 2021. The outcome measures were the absolute DNA fragmentation index (DFI) and the risk of abnormal DFI (defined as DFI ≥ 25% or ≥ 30%).

RESULTS

The mean (SD) age of men with euthyroidism and men with SCH was 34.20 (5.97) and 35.35 (6.48) years, respectively (P < 0.001). The difference in DFI was not statistically significant (adjusted mean: 19.7% vs 18.9% in the SCH and euthyroidism groups, respectively; P = 0.07) after confounder adjustment. A DFI ≥25% was significantly more frequent in men with SCH (20.57%) than in men with euthyroidism (14.49%) after confounder adjustment [odds ratio (OR) 1.43 (95% CI 1.09-1.88)]. DFI ≥ 30% was also significantly more common in men with SCH (11.72%) than in men with euthyroidism [6.74%; OR 1.84 (95% CI 1.34-2.52)]. In addition, thyroid-stimulating hormone concentration was significantly associated with an increased risk of having a DFI ≥25% (P < 0.001) or ≥30% (P = 0.011).

CONCLUSION

SCH was significantly associated with an increased risk of an abnormal DFI.

Klausen T, K. Danielsen A, Thomsen T, Bentin-Ley U, B. Knudsen U, Laursen S, R. Petersen M, Haahr K, Petersen K, Lemmen JG, Hindkjær J, Kirk J, Fedder J, J. Almind G, Hnida C, Troest B, B. Povlsen B, Zedeler A, Gabrielsen A, Larsen T, S. Kesmodel U. Is paternal age associated with transfer day, developmental stage, morphology, and initial hCG-rise of the competent blastocyst leading to live birth? A multicenter cohort study

In this study we investigated whether age of men undergoing assisted reproductive technology (ART) treatment was associated with day of transfer, stage, morphology, and initial hCG-rise of the competent blastocyst leading to a live birth? The design was a multicenter historical cohort study based on exposure (age) and outcome data (blastocyst stage and morphology and initial hCG-rise) from men whose partner underwent single blastocyst transfer resulting in singleton pregnancy/birth. The ART treatments were carried out at sixteen private and university-based public fertility clinics. We included 7246 men and women, who between 2014 and 2018 underwent controlled ovarian stimulation (COS) or Frozen-thawed Embryo Transfer (FET) with a single blastocyst transfer resulting in singleton pregnancy were identified. 4842 men with a partner giving birth were included, by linking data to the Danish Medical Birth Registry. We showed that the adjusted association between paternal age and transfer day in COS treatments was OR 1.06, 95% CI (1.00;1.13). Meaning that for every increase of one year, men had a 6% increased probability that the competent blastocyst was transferred on day 6 compared to day 5. Further we showed that the mean difference in hCG values when comparing paternal age group 30–34, 35–39 and 40–45 with the age group 25–29 in those receiving COS treatment, all showed significantly lower adjusted values for older men. In conclusion we hypothesize that the later transfer (day 6) in female partners of older men may be due to longer time spent by the oocyte to repair fragmented DNA of the sperm cells, which should be a focus of future research in men.

Separating the effects of paternal age and mating history: Evidence for sex-specific paternal effect in eastern mosquitofish

Paternal age and past mating effort by males are often confounded, which can affect our understanding of a father's age effects. To our knowledge, only a few studies have standardized mating history when testing for effects of paternal age, and none has simultaneously disentangled how paternal age and mating history might jointly influence offspring traits. Here, we experimentally manipulated male mating history to tease apart its effects from those of paternal age on female fertility and offspring traits in the eastern mosquitofish (Gambusia holbrooki). Male age did not affect female fertility. However, males with greater past mating effort produced significantly larger broods. Paternal age and mating history interacted to affect sons' body size: sons sired by old-virgin males were larger than those sired by old-mated males, but this was not the case for younger fathers. Intriguingly, however, sons sired by old-virgin males tended to produce fewer sperms than those sired by old-mated males, indicating a potential trade-off in beneficial paternal effects. Finally, neither paternal age nor mating history affected daughter's fitness. Our results highlight that variation in offspring traits attributed to paternal age effect could partly arise due to a father's mating history, and not simply to his chronological age.

Assisted reproductive technology and childhood morbidity: a longitudinal cohort study

OBJECTIVE

To evaluate the association between assisted reproductive technology (ART) and offspring morbidity in the first decade of life.

DESIGN

Longitudinal cohort study.

SETTING

Provincial health registry in Quebec, Canada.

PATIENT(S)

A total of 797,654 singleton children born between 2008 and 2019, followed up to 2020.

INTERVENTION(S)

Retrospective, noninterventional study of any ART procedure vs. no ART.

MAIN OUTCOME MEASURE(S)

Childhood morbidity, including hospitalization for infectious, allergic, malignant, and other diseases, assessed using adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association with ART. We controlled for unmeasured family-level confounders that were shared among siblings through stratified Cox regression. To do so, we restricted the analysis to 10,097 siblings with discordant exposure to ART and compared the risk of outcomes in exposed vs. unexposed siblings.

RESULT(S)

Compared with no ART, ART was associated with 1.23 times the risk of any hospitalization (95% CI 1.19-1.27), 1.25 times the risk of infectious disease hospitalization (95% CI 1.21-1.29), and 1.25 times the risk of allergy hospitalization (95% CI 1.14-1.38). When we used a sibling design to control for shared genetic and environmental confounders, ART was not associated with a greater risk of childhood hospitalization (HR 0.92, 95% CI 0.78-1.08).

CONCLUSION(S)

ART is associated with an elevated risk of hospitalization up to 11 years of age, but discordant sibling analysis suggests that the association may be due to genetic, environmental, or other shared familial confounders.

Normal-Range Paternal Serum-Free Thyroxine Concentrations and Outcomes of Assisted Reproductive Technologies

Background: A recent study showed that paternal subclinical hypothyroidism adversely affects the clinical outcomes of assisted reproductive technologies (ARTs). The aim of this study was to determine whether paternal serum-free thyroxine (fT4) concentrations within the reference range are associated with ART outcomes. Methods: This retrospective cohort study included 4066 couples who received 4894 ART treatment cycles in our clinic between April 1, 2016 and August 31, 2021. The differences in sperm parameters and ART outcomes across the paternal fT4 concentration tertiles were compared by using generalized linear models or generalized estimation equation models. The primary outcomes were clinical pregnancy rate (CPR) and live birth rate (LBR) per oocyte retrieval after the first embryo transfer cycle. Results: The mean ages of the males and their female partners were 32.8 (standard deviation, 5.0) and 30.7 (standard deviation, 4.1) years, respectively. No significant differences were observed in the sperm parameters or ART outcomes between the paternal fT4 concentration tertiles of the overall population. However, a stratified analysis of men aged ≥35 showed an adjusted CPR of 0.36 [confidence interval, CI: 0.27-0.45] for the lower paternal fT4 concentration tertile relative to the middle (adjusted rate: 0.45, CI: 0.38-0.53) and upper (adjusted rate: 0.43, CI: 0.36-0.51) tertiles (p for trend >0.05). The adjusted LBRs were 0.21 [CI: 0.15-0.30] for men aged ≥35 in the lower fT4 concentration tertile (p = 0.024, with reference to the upper tertile), 0.27 [CI: 0.21-0.35] for those in the middle tertile, and 0.30 [CI: 0.23-0.38] for those in the upper tertile. No differences in these outcomes were observed in men aged <35. The nonlinear smoothing curve obtained by using fT4 concentration as a continuous variable further supported these findings. Conclusions: Men of older reproductive age (≥35 years old) with low-normal fT4 concentrations within the reference range are associated with a decreased LBR. Future prospective studies are warranted to confirm the detrimental effects of low-normal paternal fT4 concentrations on ART outcomes.

Birth order differences in education originate in postnatal environments

Siblings share many environments and much of their genetics. Yet, siblings turn out different. Intelligence and education are influenced by birth order, with earlier-born siblings outperforming later-borns. We investigate whether birth order differences in education are caused by biological differences present at birth, that is, genetic differences or in utero differences. Using family data that spans two generations, combining registry, survey, and genotype information, this study is based on the Norwegian Mother, Father, and Child Cohort Study (MoBa). We show that there are no genetic differences by birth order as captured by polygenic scores (PGSs) for educational attainment. Earlier-born have lower birth weight than later-born, indicating worse uterine environments. Educational outcomes are still higher for earlier-born children when we adjust for PGSs and in utero variables, indicating that birth order differences arise postnatally. Finally, we consider potential environmental influences, such as differences according to maternal age, parental educational attainment, and sibling genetic nurture. We show that birth order differences are not biological in origin, but pinning down their specific causes remains elusive.

Age-Related Decline of Male Fertility: Mitochondrial Dysfunction and the Antioxidant Interventions

Mitochondria are structurally and functionally unique organelles in male gametes. Apparently, as the only organelles remaining in mature sperm, mitochondria not only produce adeno-sine triphosphate (ATP) through oxidative phosphorylation (OXPHOS) to support sperm mobility, but also play key roles in regulating reactive oxidation species (ROS) signaling, calcium homeostasis, steroid hormone biosynthesis, and apoptosis. Mitochondrial dysfunction is often associated with the aging process. Age-dependent alterations of the epididymis can cause alterations in sperm mitochondrial functioning. The resultant cellular defects in sperm have been implicated in male infertility. Among these, oxidative stress (OS) due to the overproduction of ROS in mitochondria may represent one of the major causes of these disorders. Excessive ROS can trigger DNA damage, disturb calcium homeostasis, impair OXPHOS, disrupt the integrity of the sperm lipid membrane, and induce apoptosis. Given these facts, scavenging ROS by antioxidants hold great potential in terms of finding promising therapeutic strategies to treat male infertility. Here, we summarize the progress made in understanding mitochondrial dysfunction, aging, and male infertility. The clinical potential of antioxidant interventions was also discussed.

Parenthood aspirations and understanding of factors that affect the chance of achieving them: A population survey

Most women and men want and expect to have children. Parental age and some health behaviours affect fertility and the chance of conception. The aim of this study was to gauge people's parenthood aspirations and knowledge about the factors that affect their chance of achieving them. Members of an Australian probability-based online panel aged 18-45 years were invited to complete a survey with questions about parenthood goals and knowledge about factors known to affect fertility. Of the 965 eligible people, 716 (74.2%) completed the survey. Only 6% stated that they did not want biological children. Around one in 10 respondents had experienced infertility. Amongst respondents aged 35-45 years, almost one in five (18%) had experienced infertility. Overall, respondents reported high levels of confidence about their understanding of preventative measures associated with safe sex and avoiding unwanted pregnancies. However, confidence in understanding of factors affecting ability to conceive was lower. Almost one-third of respondents believed that female fertility starts to decline between the ages of 35 and 39 years, and another one-third of respondents believed that the decline starts at 40 years of age or later. One in four respondents believed that male fertility starts to decline at 50 years of age or later. Findings suggest that people of reproductive age in Australia have inadequate knowledge about the factors that affect the chance of achieving their parenthood goals. Fertility health education initiatives are needed to allow people to make informed decisions about childbearing, and reduce the risk of unfulfilled parenthood aspirations.

Like Father, Like Child? Paternal Age at Birth and Offspring’s Facial Asymmetry and Distinctiveness

Paternal age at birth, a potential proxy of mutation load transmitted to the offspring, has previously been related to the offspring’s health, biological condition and reproductive potential. As higher facial asymmetry and distinctiveness serve as putative markers of the lower genetic quality of an individual, we hypothesize that more advanced paternal age at birth will be related to children’s higher levels of facial asymmetry and distinctiveness. To the best of our knowledge, this is the first study evaluating the link between paternal age at birth and facial asymmetry in offspring. Based on archived photographs of 159 children born within 47 Polish families, we have conducted facial geometric morphometric measurements and calculated the levels of facial asymmetry and distinctiveness. The relationship between paternal age at birth and the offspring’s facial features was explored with the use of Bayesian Linear Mixed-effects Models, controlling for sex, age and birth order of the offspring, and maternal age at child’s birth. No associations between paternal age at birth and facial asymmetry or distinctiveness in children were found. The lack of such a relationship might be a result of the potentially insufficient influence of newly accumulated paternal mutations affecting the offspring’s phenotype or higher importance of maternal (prenatal) and postnatal environments in shaping facial features.

Parental age and retinoblastoma-a retrospective study of demographic data and genetic analysis

OBJECTIVE

To determine the association between the parental age gap and the absolute parental age with the risk of retinoblastoma (RB) development in an offspring.

METHODS

RB individuals diagnosed between March 2013 and December 2019 in a single tertiary eye care centre were included. We recorded the demographic data, parental age and RB1 gene mutation status in the patient's tumour, blood and the parental blood. We categorised RB1 mutation inheritance as sporadic RB with somatic mutations (only present in tumour), heritable RB with de novo (present in patient's blood) and familial (present in patient and parents' blood) germline mutations. The statistical significance was confirmed by Fisher's exact/Chi-square test.

RESULTS

Out of 259 RB patients, 247 were included in our study. Heritable RB with de novo germline mutations was significantly less common (p value: 0.0387; 95% CI: 0.2676-0.9329) and sporadic RB with somatic mutations was more common (p value: 0.0545; 95% CI: 1.025-3.39), if the parental age gap was <10 years. There were increased odds of a heritable RB with de novo germline mutation with an increase in paternal age and this was more intensified when combined with parental age gap of more than ≥10 years. The heritable RB with de novo germline mutations significantly increased as maternal age progressed, only when it was adjusted to ≥10 years parental age gap (p value: 0.0262; 95% CI: 1.26-17.91).

CONCLUSIONS

An increased parental age gap and increased paternal age are independent risk factors for the development of heritable RB with de novo germline mutation.

Seminal Plasma and Seminal Plasma Exosomes of Aged Male Mice Affect Early Embryo Implantation via Immunomodulation

Seminal plasma (SP), particularly SP exosomes (sExos), alters with age and can affect female mouse uterine immune microenvironment. However, the relationship between fertility decline in reproductively older males, and SP and sExos age-related changes, which may compromise the uterine immune microenvironment, remains unclear. The present study demonstrated that the implantation rate of female mice treated with SP from reproductively older male mice (aged-SP group) was lower than that of those treated with SP from younger male mice (young-SP group). RNA-sequencing analysis revealed altered levels of dendritic cell (DC)-related cytokines and chemokines in the uteri of the former group compared with those of the latter group. In vivo and in vitro experiments demonstrated a weaker inhibitory effect of aged SP on DC maturation than of young SP upon stimulation. After isolating and characterizing sExos from young and advanced-age male mice, we discovered that insemination of a subset of the aged-SP group with sExos from young male mice partially recovered the implantation rate decline. Additional in vivo and in vitro experiments revealed that sExos extracted from age male mice exerted a similar effect on DC maturation as SP of aged mice, indicating an age-related sExos inhibitory effect. In conclusion, our study demonstrated that age-related alterations of sExos may be partially responsible for lower implantation rates in the aged-SP group compared with those in the young-SP group, which were mediated by uterine immunomodulation. These findings provide new insights for clinical seminal adjuvant therapy.

Study to establish visual acuity norms with Teller Acuity Cards II for infants from southern China

OBJECTIVES

To establish the norms of binocular and monocular acuity and interocular acuity differences for southern Chinese infants and compare these norms with the results for northern Chinese infants.

METHODS

A prospective, comparative, and noninterventional study was conducted from January to August 2018. Teller Acuity Cards II were used to determine the binocular and monocular acuity of infants. The tolerance intervals and limits with a stated proportion and probability were used to evaluate the norms of binocular and monocular acuity and interocular acuity differences. An unpaired t-test was used to compare the obtained norms with the reported northern Chinese norms.

RESULTS

The tolerance intervals of binocular acuity (mean acuity of 3.73, 7.35, and 12.01 cpd, respectively, at 12, 24, and 36 months), monocular acuity (mean acuity of 2.88, 6.91, and 10.75 cpd, respectively, at 12, 24, and 36 months), and interocular acuity differences (mean difference of 0.92, 2.89, and 3.99 cpd, respectively, at 12, 24, and 36 months) were obtained, exhibiting an increasing trend with age. The binocular visual acuity norms of southern Chinese infants were significantly lower than those in northern China (4.37 vs. 6.9 cpd at 8 months and 7.35 vs. 26 cpd at 24 months) (P = 0.011).

CONCLUSIONS

Northern and southern Chinese infants exhibited distinct acuity norms and visual development patterns. The establishment of population-specific visual acuity norms is necessary for current populations of infants from different regions.

The role of sperm and oocyte in fetal programming: Is Lamarck making a comeback?

Compelling evidence has shown that parental experiences and age at conception may potentially shape the future health of the next generation(s). Certain factors may affect both the female and, strikingly, the male gametes potentially causing the transmission of acquired traits, which was strongly defended by Jean-Baptiste Lamarck. Neurodevelopmental psychiatric disorders, trinucleotide repeat-associated diseases, cardiovascular pathologies, diabetes, obesity and cancer in the offspring, among others, have now been associated with events occurring at the preconception level. The potential implications of a (trans)generational inheritance of parental disease and exposure effects should be taken into account in counselling and public policy. Further research into how exactly gametes apparently deliver more than DNA to a new generation is warranted.

Social sperm freezing

Increased paternal age has been associated with lower fertility and higher genetic risk for the offspring. One way to prevent these consequences is to freeze sperm at a young age. Social sperm freezing could be developed in a way similar to social oocyte freezing. The main difference between freezing oocytes and sperm is that social sperm freezing is much less focussed on fertility preservation and much more on avoiding increased genetic risk. Contrary to what some people seem to believe, sperm freezing is more complicated than it looks at first sight. This article considers three practical aspects: freezing, storage and testing. It is concluded that the remedy (cryopreservation) may itself cause damage to the quality of the spermatozoon and to its genetic integrity, thus undoing the possible benefits in terms of fertility and health of offspring.

Male age interferes with embryo growth in IVF treatment

STUDY QUESTION

Does male age affect embryo growth or quality in couples undergoing IVF treatment?

SUMMARY ANSWER

Advanced paternal age (APA) is negatively associated with the chance of an optimal eight-cell embryo on the third day of development.

WHAT IS KNOWN ALREADY

Literature shows that APA is associated with decreased sperm quality and fecundity. However, the effect of male age on embryo growth in an IVF setting remains inconclusive. Literature concerning male influences on IVF success is scarce and approaches used to analyse embryo outcomes differ by study.

STUDY DESIGN, SIZE, DURATION

This study was part of the longitudinal Epigenetic Legacy of Paternal Obesity (ELPO) study for which fathers and mothers were followed from pre-pregnancy until the birth of their child. Couples were recruited from April 2015 to September 2017. A total of 1057 embryos from 87 couples were studied.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Dutch-speaking couples planning to undergo an IVF treatment were recruited at the Leuven University Fertility Center in Flanders, Belgium. Anthropometrics were documented and compared to the general Flemish population. Semen characteristics, pregnancy rates and the following embryo characteristics were recorded: number of blastomeres, symmetry and percentage fragmentation. Statistical modelling was applied taking into account correlation of within-cycle outcomes and use of multiple cycles per couple.

MAIN RESULTS AND THE ROLE OF CHANCE

We observed a significant inverse association between APA and a key determinant for scoring of embryo quality: older men were less likely to produce an embryo of eight blastomeres at Day 3, compared to younger fathers; odds ratio for the effect of 1 year equals 0.960 (95% CI: 0.930-0.991; P = 0.011). Our finding remained significant after adjusting for female age and male and female BMI. Degree of fragmentation and symmetry were not significantly related to male age.

LIMITATIONS, REASONS FOR CAUTION

Because of the study's small sample size and its monocentric nature, a larger study is warranted to confirm our results. In addition, distribution of BMI and level of education were not representative of the general Flemish population. Although we corrected for BMI status, we do not exclude that obesity may be one of the determinants of infertility in our study population. Furthermore, it is known from other European countries that a higher education eases access to fertility treatment. Hence, caution should be taken when interpreting our findings from a fertility setting to the general population.

WIDER IMPLICATIONS OF THE FINDINGS

We suggest a heightened need for future research into male age and its potential effects on embryo growth, embryo quality and ART outcomes. Clinical decision-making and preventative public health programmes would benefit from a better understanding of the role of men, carried forward by the Paternal Origins of Health and Disease (POHaD) paradigm. We hope the current finding will encourage others to examine the role of the sperm epigenome in embryo development according to paternal age.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a research grant from KU Leuven University (OT/14/109). The authors declare no competing financial, professional or personal interests.

TRIAL REGISTRATION NUMBER

KU Leuven S57378 (ML11309), B322201523225.

Effects of exposure to methylglyoxal on sperm motility and embryonic development after fertilization in mice

Methylglyoxal (MG) is a precursor for the generation of endogenous advanced glycation end-products involved in various diseases, including infertility. The present study evaluated the motility and developmental competence after in vitro fertilization of mouse sperm which were exposed to MG in the capacitation medium for 1.5 h. Sperm motility was analyzed using an SQA-V automated sperm quality analyzer. Intracellular reactive oxygen species (ROS), membrane integrity, mitochondrial membrane potential, and DNA damage were assessed using flow cytometry. The matured oocytes were inseminated with MG-exposed sperm, and subsequently, the fertilization and embryonic development in vitro were evaluated in vitro. The exposure of sperm to MG did not considerably affect the swim-up of sperm but resulted in a deteriorated sperm motility in a concentration-dependent manner, which was associated with a decreased mitochondrial activity. However, these effects was not accompanied by obvious ROS accumulation or DNA damage. Furthermore, MG diminished the fertilization rate and developmental competence, even after normal fertilization. Collectively, a short-term exposure to MG during sperm capacitation had a critical impact on sperm motility and subsequent embryonic development after fertilization. Considering that sperm would remain in vivo for up to 3 days until fertilization, our findings suggest that sperm can be affected by MG in the female reproductive organs, which may be associated with infertility.

Impact of maternal age on infants' emotional regulation and psychomotor development

BACKGROUND

Maternal age has progressively increased in industrialized countries. Most studies focus on the consequences of delayed motherhood for women's physical and mental health, but little is known about potential effects on infants' neurodevelopment. This prospective study examines the association between maternal age and offspring neurodevelopment in terms of both psychomotor development (Ages & Stages Questionnaires-3) and emotional competences (Early Childhood Behavior Questionnaire).

METHODS

We evaluated a cohort of healthy pregnant women aged 20-41 years and their offspring, assessed at 38 weeks gestation (n = 131) and 24 months after birth (n = 101). Potential age-related variables were considered (paternal age, education level, parity, social support, maternal cortisol levels, and maternal anxiety and depressive symptoms). Bayesian ordinal regression models were performed for each neurodevelopmental outcome.

RESULTS

Maternal age was negatively associated with poor child development in terms of personal-social skills [odds ratio (OR) -0.13, 95% confidence interval (CI) 0.77-0.99] and with difficult temperament in terms of worse emotional regulation (OR -0.13, 95% CI 0.78-0.96) and lower positive affect (OR 0.16, 95% CI 0.75-0.95). As for age-related variables, whereas maternal anxiety symptoms and cortisol levels were also correlated with poor child development and difficult temperament, maternal social support and parental educational level were associated with better psychomotor and emotional competences.

CONCLUSION

Increasing maternal age may be associated with child temperament difficulties and psychomotor delay in terms of social interaction skills. Early detection of neurodevelopment difficulties in these babies would allow preventive psychosocial interventions to avoid future neuropsychiatric disorders.

Influence of age on sperm characteristics evaluated by light and electron microscopies

The impact of male aging on male fertility has only recently become of interest to the scientific community. This study aims to assess the relationship between age and fertility among a sample of men, considering the individual and pathological characteristics. In this retrospective study data of semen analysis and medical history of 1294 Italian male patients were considered. Semen analysis was performed by light microscopy and transmission electron microscopy mathematically elaborated. A generalized linear model was used to explore the influence of male age on semen quality, considering as confounders wine consumption, smoking habits, presence of varicocele, consanguinity and positive semen bacteriological analysis and urethral swab. The mean age of the participants was 36.41 ± 6.379. Male aging without impact of confounders was correlated with a decrease in sperm concentration and motility and an increased in sperm necrosis. Sperm concentration and progressive motility were negatively related to the presence of confounders as wine consumption (sperm motility), urogenital infection (sperm concentration and motility), varicocele (sperm concentration) and consanguinity (sperm motility). Urogenital infection, varicocele and consanguinity positively correlated with sperm necrosis. The most important finding was the observation of a negative effect of male aging on sperm parameters such as concentration, motility, and viability. It is possible to hypothesize age-dependent changes of testicular environment, probably related to reactive oxygen species production. The demonstration, in a large sample of patients, that aging influences sperm quality strongly motivates further research focused on the mechanisms involved in this phenomenon and its effects on offspring fitness.

The European Academy of Andrology (EAA) ultrasound study on healthy, fertile men: Scrotal ultrasound reference ranges and associations with clinical, seminal, and biochemical characteristics

BACKGROUND

Scrotal color Doppler ultrasound (CDUS) still suffers from lack of standardization. Hence, the European Academy of Andrology (EAA) has promoted a multicenter study to assess the CDUS characteristics of healthy fertile men (HFM) to obtain normative parameters.

OBJECTIVES

To report and discuss the scrotal organs CDUS reference ranges and characteristics in HFM and their associations with clinical, seminal, and biochemical parameters.

METHODS

A cohort of 248 HFM (35.3 ± 5.9years) was studied, evaluating, on the same day, clinical, biochemical, seminal, and scrotal CDUS following Standard Operating Procedures.

RESULTS

The CDUS reference range and characteristics of the scrotal organs of HFM are reported here. CDUS showed a higher accuracy than physical examination in detecting scrotal abnormalities. Prader orchidometer (PO)- and US-measured testicular volume (TV) were closely related. The US-assessed TV with the ellipsoid formula showed the best correlation with the PO-TV. The mean TV of HFM was ~ 17 ml. The lowest reference limit for right and left testis was 12 and 11 ml, thresholds defining testicular hypotrophy. The highest reference limit for epididymal head, tail, and vas deferens was 12, 6, and 4.5 mm, respectively. Mean TV was associated positively with sperm concentration and total count and negatively with gonadotropins levels and pulse pressure. Subjects with testicular inhomogeneity or calcifications showed lower sperm vitality and concentration, respectively, than the rest of the sample. Sperm normal morphology and progressive motility were positively associated with epididymal head size/vascularization and vas deferens size, respectively. Increased epididymis and vas deferens sizes were associated with MAR test positivity. Decreased epididymal tail homogeneity/vascularization were positively associated with waistline, which was negatively associated with intratesticular vascularization. CDUS varicocele was detected in 37.2% of men and was not associated with seminal or hormonal parameters. Scrotal CDUS parameters were not associated with time to pregnancy, number of children, history of miscarriage.

CONCLUSIONS

The present findings will help in better understanding male infertility pathophysiology, improving its management.

Paternal Subclinical Hypothyroidism Affects the Clinical Outcomes of In Vitro Fertilization/Intracytoplasmic Sperm Injection

Background: Maternal subclinical hypothyroidism (SCH) is a risk factor for adverse pregnancy outcomes. However, it is still unclear whether SCH affects male fertility. The aim of this study was to determine the association between paternal SCH and clinical outcomes after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Methods: This retrospective study included 2511 couples with paternal euthyroidism (n = 2282) or SCH (n = 229) who visited our clinic for infertility treatment between April 1, 2017, and September 30, 2019. The primary outcomes were the fertilization rate and clinical pregnancy rate; the secondary outcomes were the good-quality embryo rate, blastocyst formation rate, implantation rate, and early miscarriage rate. These outcomes were compared between the euthyroid and the SCH groups after adjusting for various potential confounders. Results: The mean paternal ages in the euthyroid and SCH groups were 34.5 and 36.0 years, respectively (p = 0.002). Semen parameters and sperm DNA fragmentation index were similar between the two groups (all p > 0.05). The adjusted fertilization (0.69 vs. 0.71, p = 0.30), good-quality embryo (0.49 vs. 0.52, p = 0.31), blastocyst formation (0.51 vs. 0.53, p = 0.57), and early miscarriage (0.11 vs. 0.10, p = 0.81) rates were also similar between the two groups. There was a significantly decreased adjusted clinical pregnancy rate [confidence interval, CI] and implantation rate [CI] in the paternal SCH group compared with the euthyroid group (0.32 [0.26-0.40] vs. 0.42 [0.40-0.45], p = 0.009 for the clinical pregnancy rate; 0.24 [0.19-0.29] vs. 0.29 [0.27-0.31], p = 0.037 for the implantation rate). Stratified analysis indicated that these differences were only significant in men aged ≥35 years (p = 0.009 and 0.022, respectively) and not in men <35 years (p = 0.39 and 0.45, respectively). Conclusions: Paternal SCH was associated with worse clinical outcomes after IVF/ICSI, whereas this detrimental impact was only present in males ≥35 years old. Prospective studies and basic research are warranted to confirm these results and to clarify the mechanisms underlying these associations, respectively.

Is there an association between paternal age and aneuploidy? Evidence from young donor oocyte-derived embryos: a systematic review and individual patient data meta-analysis

BACKGROUND

Delayed parenthood, by both women and men, has become more common in developed countries. The adverse effect of advanced maternal age on embryo aneuploidy and reproductive outcomes is well known. However, whether there is an association between paternal age (PA) and embryonic chromosomal aberrations remains controversial. Oocyte donation (OD) is often utilized to minimize maternal age effects on oocyte and embryo aneuploidy, thus providing an optimal model to assess the effect of PA. Several studies have revealed a higher than expected rate of aneuploidy in embryos derived from young oocyte donors, which warrants examination as to whether this may be attributed to advanced PA (APA).

OBJECTIVE AND RATIONALE

The objective of this systematic review and individual patient data (IPD) meta-analysis is to evaluate existing evidence regarding an association between PA and chromosomal aberrations in an OD model.

SEARCH METHODS

This review was conducted according to PRISMA guidelines for systematic reviews and meta-analyses. Medline, Embase and Cochrane databases were searched from inception through March 2020 using the (MeSH) terms: chromosome aberrations, preimplantation genetic screening and IVF. Original research articles, reporting on the types and/or frequency of chromosomal aberrations in embryos derived from donor oocytes, including data regarding PA, were included. Studies reporting results of IVF cycles using only autologous oocytes were excluded. Quality appraisal of included studies was conducted independently by two reviewers using a modified Newcastle-Ottawa Assessment Scale. A one-stage IPD meta-analysis was performed to evaluate whether an association exists between PA and aneuploidy. Meta-analysis was performed using a generalized linear mixed model to account for clustering of embryos within patients and clustering of patients within studies.

OUTCOMES

The search identified 13 032 references, independently screened by 2 reviewers, yielding 6 studies encompassing a total of 2637 IVF-OD cycles (n = 20 024 embryos). Two 'low' quality studies using FISH to screen 12 chromosomes on Day 3 embryos (n = 649) reported higher total aneuploidy rates and specifically higher rates of trisomy 21, 18 and 13 in men ≥50 years. One 'moderate' and three 'high' quality studies, which used 24-chromosome screening, found no association between PA and aneuploidy in Day 5/6 embryos (n = 12 559). The IPD meta-analysis, which included three 'high' quality studies (n = 10 830 Day 5/6 embryos), found no significant effect of PA on the rate of aneuploidy (odds ratio (OR) 0.97 per decade of age, 95% CI 0.91-1.03), which was robust to sensitivity analyses. There was no association between PA and individual chromosome aneuploidy or segmental aberrations, including for chromosomes X and Y (OR 1.06 per decade of age, 95% CI 0.92-1.21). Monosomy was most frequent for chromosome 16 (217/10802, 2.01%, 95% CI 1.76-2.29%) and trisomy was also most frequent for chromosome 16 (194/10802, 1.80%, 95% CI 1.56-2.06%).

WIDER IMPLICATIONS

We conclude, based on the available evidence, that APA is not associated with higher rates of aneuploidy in embryos derived from OD. These results will help fertility practitioners when providing preconception counselling, particularly to older men who desire to have a child.

The other face of advanced paternal age: a scoping review of its terminological, social, public health, psychological, ethical and regulatory aspects

BACKGROUND

There is a global tendency for parents to conceive children later in life. The maternal dimension of the postponement transition has been thoroughly studied, but interest in the paternal side is more recent. For the moment, most literature reviews on the topic have focused on the consequences of advanced paternal age (APA) on fertility, pregnancy and the health of the child.

OBJECTIVE AND RATIONALE

The present review seeks to move the focus away from the biological and medical dimensions of APA and synthesise the knowledge of the other face of APA.

SEARCH METHODS

We used the scoping review methodology. Searches of interdisciplinary articles databases were performed with keywords pertaining to APA and its dimensions outside of biology and medicine. We included scientific articles, original research, essays, commentaries and editorials in the sample. The final sample of 177 documents was analysed with qualitative thematic analysis.

OUTCOMES

We identified six themes highlighting the interdisciplinary nature of APA research. The 'terminological aspects' highlight the lack of consensus on the definition of APA and the strategies developed to offer alternatives. The 'social aspects' focus on the postponement transition towards reproducing later in life and its cultural dimensions. The 'public health aspects' refer to attempts to analyse APA as a problem with wider health and economic implications. The 'psychological aspects' focus on the consequences of APA and older fatherhood on psychological characteristics of the child. The 'ethical aspects' reflect on issues of APA emerging at the intersection of parental autonomy, children's welfare and social responsibility. The 'regulatory aspects' group different suggestions to collectively approach the implications of APA. Our results show that the field of APA is still in the making and that evidence is lacking to fully address the issues of APA. The review suggests promising avenues of research such as introducing the voice of fathers of advanced age into the research agenda.

WIDER IMPLICATIONS

The results of this review will be useful for developing policies and preconception health interventions that consider and include prospective fathers of advanced age.

A germ cell-specific ageing pattern in otherwise healthy men

Life‐long sperm production leads to the assumption that male fecundity remains unchanged throughout life. However, recently it was shown that paternal age has profound consequences for male fertility and offspring health. Paternal age effects are caused by an accumulation of germ cell mutations over time, causing severe congenital diseases. Apart from these well‐described cases, molecular patterns of ageing in germ cells and their impact on DNA integrity have not been studied in detail. In this study, we aimed to assess the effects of ‘pure’ ageing on male reproductive health and germ cell quality. We assembled a cohort of 198 healthy men (18–84 years) for which end points such as semen and hormone profiles, sexual health and well‐being, and sperm DNA parameters were evaluated. Sperm production and hormonal profiles were maintained at physiological levels over a period of six decades. In contrast, we identified a germ cell‐specific ageing pattern characterized by a steady increase of telomere length in sperm and a sharp increase in sperm DNA instability, particularly after the sixth decade. Importantly, we found sperm DNA methylation changes in 236 regions, mostly nearby genes associated with neuronal development. By in silico analysis, we found that 10 of these regions are located in loci which can potentially escape the first wave of genome‐wide demethylation after fertilization. In conclusion, human male germ cells present a unique germline‐specific ageing process, which likely results in diminished fecundity in elderly men and poorer health prognosis for their offspring.

An age-based sperm nomogram: the McGill reference guide

STUDY QUESTION

How does age affect various semen parameters?

SUMMARY ANSWER

For most semen parameters, the nomogram of the entire population was biphasic, peaking around the fourth decade of life.

WHAT IS KNOWN ALREADY

In clinical practice, semen quality is examined by using the WHO 2010 reference limits but these limits do not account for male age. A percentile-based, large-scale nomogram describing how different semen parameters change throughout reproductive life has been lacking.

STUDY DESIGN, SIZE, DURATION

A retrospective study was conducted with 12 188 sperm samples, obtained from individuals who attended the McGill University Health Centre reproductive clinic between 2009 and 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

One sample from each individual who attended the clinic during the study period was analysed by using computer-assisted sperm analysis (CASA). The analysed parameters were human-verified and included sperm concentration, motility, progressive motility, total count, morphology and semen volume. Based on this analysis, the entire dataset (n = 12 188) was further divided into two groups of samples: samples that surpassed the WHO 2010 lower reference limits (‘above reference limits’ group, ARL; n = 6305), and samples that did not (‘below reference limit’ group, BRL; n = 5883). Regression quantiles were fitted as a function of age to generate age-dependent nomograms, and these quantiles were divided into 5th, 25th, 50th, 75th and 95th percentiles.

MAIN RESULTS AND THE ROLE OF CHANCE

In the entire dataset, age had a significant influence (P &lt; 0.001) on all parameters (except morphology) which demonstrated a biphasic trend peaking in the fourth decade of life. In the ARL group, age had a significant influence (P &lt; 0.01) on all semen parameters except sperm concentration and morphology. However, unlike in the entire dataset, only semen volume demonstrated a biphasic trend in the ARL group (peaking in the fourth decade of life), whereas other parameters either remained unchanged (concentration and morphology) or consistently declined with age (sperm motility, progressive motility and total sperm count). Percentile-based nomograms were generated for individuals between the ages of 20 and 60 years in the entire dataset and in the ARL group.

LIMITATIONS, REASONS FOR CAUTION

First, the semen samples were obtained from individuals who were referred to a fertility clinic, such that the entire dataset does not necessarily represent the general population. Second, the cross-sectional sampling design increases variance, and the nomograms are less accurate in the 5th and 95th percentiles and at the extremes of the age distributions. Third, the observed age-dependent changes in semen parameters do not necessarily indicate changes in fertility, as not all factors that affect male fertility were analysed. Fourth, some of our semen analyses employed CASA, which can have variability issues. Finally, our models did not incorporate possible secular trends.

WIDER IMPLICATIONS OF THE FINDINGS

We provide the first nomogram that correlates age with semen quality parameters in different population percentiles, thus complementing the current reference limits set by the WHO in 2010. Most examined semen parameters in our study changed non-linearly with age; therefore, age should be regularly employed as a factor in the clinical analysis of semen samples.

STUDY FUNDING/COMPETING INTEREST(S)

The authors have not received any funding to support this study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Is perception of inability to procreate a temporal phenomenon?: A longitudinal exploration of changes and determinants among women and men of reproductive age in Germany

Continued postponement of births and increasing use of reproductive medicine enhance the relevance of infertility and related perceptions for fertility research. Fertility researchers tend to assume that an existing perception of inability to procreate is a stable trait among persons of reproductive age. This assumption is questionable from a life course perspective and has not been thoroughly investigated. Therefore we investigate the prevalence, stability, and correlates of perceived inability to procreate. We apply between-within logit models to annual panel data (2008-2015) to study variation in perceived inability to procreate within individuals over time and between individuals. We find that approximately every 20th person of reproductive age is affected. There is considerable instability among those who ever perceive an inability to procreate: On average, 39 % of women and 48 % of men who perceive an inability in one year change to not perceiving an inability in the next year. Multivariate analysis shows that increases in age and perception of one's partner as unable to procreate are associated with higher odds of perceiving an inability to procreate. Not using contraception is associated with higher odds of perceiving an inability to procreate. Perceived procreative ability further differs by parity, level of education, immigration background, and religious denomination. In summary, perception of inability to procreate is a temporal phenomenon that is shaped by lifecourse contexts and social group differences.

Advanced paternal age is associated with an increased risk of spontaneous miscarriage: a systematic review and meta-analysis

BACKGROUND

Although spontaneous miscarriage is the most common complication of human pregnancy, potential contributing factors are not fully understood. Advanced maternal age has long been recognised as a major risk factor for miscarriage, being strongly related with fetal chromosomal abnormalities. The relation between paternal age and the risk of miscarriage is less evident, yet it is biologically plausible that an increasing number of genetic and epigenetic sperm abnormalities in older males may contribute to miscarriage. Previous meta-analyses showed associations between advanced paternal age and a broad spectrum of perinatal and paediatric outcomes. This is the first systematic review and meta-analysis on paternal age and spontaneous miscarriage.

OBJECTIVE AND RATIONALE

The aim of this systematic review and meta-analysis is to evaluate the effect of paternal age on the risk of spontaneous miscarriage.

SEARCH METHODS

PubMed, Embase and Cochrane databases were searched to identify relevant studies up to August 2019. The following free text and MeSH terms were used: paternal age, father's age, male age, husband's age, spontaneous abortion, spontaneous miscarriage, abortion, miscarriage, pregnancy loss, fetal loss and fetal death. PRISMA guidelines for systematic reviews and meta-analysis were followed. Original research articles in English language addressing the relation between paternal age and spontaneous miscarriage were included. Exclusion criteria were studies that solely focused on pregnancy outcomes following artificial reproductive technology (ART) and studies that did not adjust their effect estimates for at least maternal age. Risk of bias was qualitatively described for three domains: bias due to confounding, information bias and selection bias.

OUTCOMES

The search resulted in 975 original articles. Ten studies met the inclusion criteria and were included in the qualitative synthesis. Nine of these studies were included in the quantitative synthesis (meta-analysis). Advanced paternal age was found to be associated with an increased risk of miscarriage. Pooled risk estimates for miscarriage for age categories 30-34, 35-39, 40-44 and ≥45 years of age were 1.04 (95% CI 0.90, 1.21), 1.15 (0.92, 1.43), 1.23 (1.06, 1.43) and 1.43 (1.13, 1.81) respectively (reference category 25-29 years). A second meta-analysis was performed for the subgroup of studies investigating first trimester miscarriage. This showed similar pooled risk estimates for the first three age categories and a slightly higher pooled risk estimate for age category ≥45 years (1.74; 95% CI 1.26, 2.41).

WIDER IMPLICATIONS

Over the last decades, childbearing at later ages has become more common. It is known that frequencies of adverse reproductive outcomes, including spontaneous miscarriage, are higher in women with advanced age. We show that advanced paternal age is also associated with an increased risk of spontaneous miscarriage. Although the paternal age effect is less pronounced than that observed with advanced maternal age and residual confounding by maternal age cannot be excluded, it may have implications for preconception counselling of couples comprising an older aged male.

'Doing it in the right order': childless men's intentions regarding family formation

In high-income countries, parental age at first birth has increased and this postponement increases the risk of involuntary childlessness or having fewer children than desired. This interview study was conducted in Denmark and Sweden among childless men (n = 29) in their last year of an education. The aim was to explore the role of individual and societal factors on fertility decision-making and men's reflections on barriers and enablers for earlier family formation. Data were analysed with thematic content analysis. Almost all participants wanted children in the future. Overall, there was a desire to follow the 'right chronology': get educated, having a stable relationship, employment and a good financial status before having children. While most men felt mature enough to have children, they were still not ready. Influences from within the inner social circle, societal expectations, the need for security and stability and being ready to give up freedom and individuality were factors that affected participants' preferred timing of parenthood. Most men did not have suggestions for how earlier family formation could be supported. Results suggest a gap between the ideal biological and ideal social age of family formation that may lead to unfulfilled parenthood aspirations.