Advanced paternal age and risk of fetal death: a cohort study

Naturally occurring horse model of miscarriage reveals temporal relationship between chromosomal aberration type and point of lethality

Chromosomal abnormalities are a common cause of human miscarriage but rarely reported in any other species. As a result, there are currently inadequate animal models available to study this condition. Horses present one potential model since mares receive intense gynecological care. This allowed us to investigate the prevalence of chromosomal copy number aberrations in 256 products of conception (POC) in a naturally occurring model of pregnancy loss (PL). Triploidy (three haploid sets of chromosomes) was the most common aberration, found in 42% of POCs following PL over the embryonic period. Over the same period, trisomies and monosomies were identified in 11.6% of POCs and subchromosomal aberrations in 4.2%. Whole and subchromosomal aberrations involved 17 autosomes, with chromosomes 3, 4, and 20 having the highest number of aberrations. Triploid fetuses had clear gross developmental anomalies of the brain. Collectively, data demonstrate that alterations in chromosome number contribute to PL similarly in women and mares, with triploidy the dominant ploidy type over the key period of organogenesis. These findings, along with highly conserved synteny between human and horse chromosomes, similar gestation lengths, and the shared single greatest risk for PL being advancing maternal age, provide strong evidence for the first animal model to truly recapitulate many key features of human miscarriage arising due to chromosomal aberrations, with shared benefits for humans and equids.

Relationship between male aging and semen quality: a retrospective study on over 2500 men

PURPOSE

We aimed to evaluate whether and to what extent an association exists between male aging and worsening of semen parameters and to determine whether a threshold age can be identified above which the decline in semen quality becomes statistically significant.

METHODS

2612 men (age: 16-56 years) attending an andrology outpatient clinic for semen analysis and clinical evaluation were studied. Semen analyses were performed according to the ongoing WHO-recommended procedures. Total motile count (TMC) and total progressive motile count (TPMC) were calculated by multiplying total sperm number by total motility and progressive motility, respectively.

RESULTS

Significant negative correlations were found between age and total motility (r = - 0.131, p < 0.0001), progressive motility (r = - 0.112, p < 0.0001), TPMC (r = - 0.042, p = 0.037), and normal sperm morphology (r = - 0.053, p = 0.007). All these associations persisted in multivariate regression models adjusted for abstinence time, smoking, history of male accessory gland infections, varicocele and the year in which semen analysis was performed. When comparisons were performed among quartiles of increasing age, the fourth quartile, corresponding to the age group > 40 years, was associated with a significant decrease in total and progressive motility. An earlier decline in the TPMC and percentage of normal forms was also observed.

CONCLUSION

Advancing male age exhibits an independent association with a decrease in the percentage of motile and morphologically normal spermatozoa, with greater evidence from the age of > 40 years. Further studies are warranted to elucidate the mechanisms and clinical reflections of these associations.

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.

The "Bad Father": Paternal Role in Biology of Pregnancy and in Birth Outcome

Pregnancy is generally studied as a biological interaction between a mother and a fetus; however, the father, with his characteristics, lifestyle, genetics, and living environment, is by no means unrelated to the outcome of pregnancy. The half of the fetal genetic heritage of paternal derivation can be decisive in cases of inherited chromosomal disorders, and can be the result of de novo genetic alterations. In addition to the strictly pathological aspects, paternal genetics may transmit thrombophilic traits that affect the implantation and vascular construction of the feto-placental unit, lead to placenta-mediated diseases such as pre-eclampsia and fetal growth retardation, and contribute to the multifactorial genesis of preterm delivery. Biological aspects of immunological tolerance to paternal antigens also appear to be crucial for these pathologies. Finally, this review describes the biological findings by which the environment, exposure to pathogens, lifestyle, and nutritional style of the father affect fetal pathophysiological and epigenetic definition.

Paternal age does not jeopardize the live birth rate and perinatal outcomes after in vitro fertilization: an analysis based on 56,113 frozen embryo transfer cycles

BACKGROUND

The global trend of delaying childbearing has led to an increasing number of couples seeking in vitro fertilization. The adverse effects of advanced maternal age on pregnancy and perinatal outcomes are well documented, regardless of the conception method. In addition, advanced paternal age may contribute to poor reproductive potential because of high levels of sperm DNA fragmentation. However, it remains challenging to guide older men regarding the effect of paternal age on pregnancy and birth outcomes in the field of assisted reproduction.

OBJECTIVE

This study aimed to investigate the association of paternal age with live birth and perinatal outcomes following in vitro fertilization-frozen embryo transfer.

STUDY DESIGN

A retrospective study was performed at a university-affiliated fertility center, involving women who were younger than 36 years and had undergone frozen embryo transfer from January 2011 to June 2021. Subjects were categorized into 6 groups based on paternal age: <25, 25 to 29, 30 to 34, 35 to 39, 40 to 44, and ≥45 years. A generalized estimating equation logistic regression model was used to account for the clustered nature of data and to adjust for confounders. Paternal age between 25 and 29 years served as the reference group in the logistic regression models.

RESULTS

A total of 56,113 cycles who met the inclusion criteria were included in the final analysis. On unadjusted analyses, the reproductive outcome parameters showed a considerable decline with increasing male age. The live birth rate decreased from 47.9% for men aged 25 to 29 years to 40.3% among men aged ≥40 years. Similarly, the clinical pregnancy rate decreased from 54.4% in the reference group to 47.8% in the ≥40 years age group. Conversely, the miscarriage rate increased as male age increased, from 10.2% among men aged 25 to 29 years to 13.5% among men aged ≥45 years. However, the differences in the reproductive outcomes mentioned above were no longer significant in the multivariable models. Compared with the younger controls, advanced paternal age was not associated with a lower chance of live birth (males aged 40-44 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.85-1.04; males aged ≥45 years: adjusted odds ratio, 0.93; 95% confidence interval, 0.79-1.10). In addition, the rates of clinical pregnancy (males aged 40-44 years: adjusted odds ratio, 0.95; 95% confidence interval, 0.85-1.05; males aged ≥45 years: adjusted odds ratio, 0.94; 95% confidence interval, 0.79-1.12) and miscarriage (males aged 40-44 years: adjusted odds ratio, 1.05; 95% confidence interval, 0.85-1.31; males aged ≥45 years: adjusted odds ratio, 1.07; 95% confidence interval, 0.77-1.50) were comparable between the reference and advanced paternal age groups. Furthermore, men in the youngest age group (<25 years) did not have worse pregnancy outcomes than those in the reference group. Regarding perinatal outcomes, there was no difference among the study cohorts in terms of preterm birth, low birthweight, macrosomia, small for gestational age, and large for gestational age, both in the unadjusted and confounder-adjusted models.

CONCLUSION

This study did not demonstrate a significant association between paternal age and live birth and perinatal outcomes after in vitro fertilization-frozen embryo transfer when the female partners were younger than 36 years. With the global trend toward delaying childbirth, our findings provide useful information for counseling patients that increasing paternal age may not adversely affect pregnancy and perinatal outcomes in assisted reproduction.

Donor sperm treatment: the role of semen parameters in intracervical insemination, a retrospective cohort study

Donor sperm treatment is advised to be performed with frozen-thawed donor semen. A disadvantage of frozen-thawed semen is lower pregnancy rates compared to inseminations with fresh semen. Semen parameters affect ongoing pregnancy rates in intracervical inseminations with frozen-thawed donor semen. In an attempt to translate this into clinical relevance, cohort studies have tried to find cut-off values for semen parameters after thawing for intracervical insemination, but these studies assessed only one semen parameter per study, thereby overlooking the intricate interplay between all semen parameters. We performed a retrospective cohort study and tried to calculate thresholds for all semen parameters that lead to the best possible ongoing pregnancy rates in intracervical insemination with frozen-thawed donor semen. Between April 1999 and December 2015, data from 1,186 women who underwent 7,103 cycles of intracervical insemination with donor semen from 129 sperm donors were available for analysis. Our results showed that total motility and total motile count (TMC) after thawing were associated with ongoing pregnancy rate. The best possible ongoing pregnancy chances after intracervical insemination were obtained at a total motility of ≥20% and a total motile count (TMC) of ≥8 × 106 after thawing.

The Role of Advanced Parental Age in Reproductive Genetics

The increase of parental reproductive age is a worldwide trend in modern society in recent decades. In general, older parents have a significant impact on reproductive genetics and the health of offspring. In particular, advanced parental age contributes to the increase in the risk of adverse neurodevelopmental outcomes in offspring. However, it is currently under debate how and to what extent the health of future generations was affected by the parental age. In this review, we aimed to (i) provide an overview of the effects of age on the fertility and biology of the reproductive organs of the parents, (ii) highlight the candidate biological mechanisms underlying reproductive genetic alterations, and (iii) discuss the relevance of the effect of parental age on offspring between animal experiment and clinical observation. In addition, we think that the impact of environmental factors on cognitive and emotional development of older offspring will be an interesting direction.

The role of miRNA molecules in the miscarriage process

The etiology and pathogenesis of miscarriage, which is the most common pregnancy complication, have not been fully elucidated. There is a constant search for new screening biomarkers that would allow for the early diagnosis of disorders associated with pregnancy pathology. The profiling of microRNA expression is a promising research area, which can help establish the predictive factors for pregnancy diseases. Molecules of microRNAs are involved in several processes crucial for the development and functioning of the body. These processes include cell division and differentiation, programmed cell death, blood vessel formation or tumorigenesis, and the response to oxidative stress. The microRNAs affect the number of individual proteins in the body due to their ability to regulate gene expression at the post-transcriptional level, ensuring the normal course of many cellular processes. Based on the scientific facts available, this paper presents a compendium on the role of microRNA molecules in the miscarriage process. The expression of potential microRNA molecules as early minimally invasive diagnostic biomarkers may be evaluated as early as the first weeks of pregnancy and may constitute a monitoring factor in the individual clinical care of women in early pregnancy, especially after the first miscarriage. To summarize, the described scientific data set a new direction of research in the development of preventive care and prognostic monitoring of the course of pregnancy.

Impact of Advanced Paternal Age on Fertility and Risks of Genetic Disorders in Offspring

The average age of fathers at first pregnancy has risen significantly over the last decade owing to various variables, including a longer life expectancy, more access to contraception, later marriage, and other factors. As has been proven in several studies, women over 35 years of age have an increased risk of infertility, pregnancy problems, spontaneous abortion, congenital malformations, and postnatal issues. There are varying opinions on whether a father's age affects the quality of his sperm or his ability to father a child. First, there is no single accepted definition of old age in a father. Second, much research has reported contradictory findings in the literature, particularly concerning the most frequently examined criteria. Increasing evidence suggests that the father's age contributes to his offspring's higher vulnerability to inheritable diseases. Our comprehensive literature evaluation shows a direct correlation between paternal age and decreased sperm quality and testicular function. Genetic abnormalities, such as DNA mutations and chromosomal aneuploidies, and epigenetic modifications, such as the silencing of essential genes, have all been linked to the father's advancing years. Paternal age has been shown to affect reproductive and fertility outcomes, such as the success rate of in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and premature birth rate. Several diseases, including autism, schizophrenia, bipolar disorders, and paediatric leukaemia, have been linked to the father's advanced years. Therefore, informing infertile couples of the alarming correlations between older fathers and a rise in their offspring's diseases is crucial, so that they can be effectively guided through their reproductive years.

Multivariable analysis to determine risk factors associated with abortion in mares

Risk factors associated with equine reproductive efficiency have been identified along with those associated specifically with early pregnancy loss (EPL). In contrast, no studies have reported risk factors associated with abortion (loss between day 70 and 300 post-cover). Given the causes of abortion differ to those of EPL, likely too will the risk factors. A retrospective cohort study was carried out to identify risk factors associated with abortion in UK and Irish based Thoroughbreds, collecting data on 20 exposure variables over a five-year period. A generalized linear mixed model was utilized to evaluate the associations between exposure variables and abortion, with clustering of observations accounted for at the mare and farm level. Variables with a likelihood ratio test (LRT) p value <0.2 were entered into the model in a forward stepwise approach. Pregnancy outcome was available on 4,439 pregnancies from 2,510 mares. Having had two or more prior abortions (odds ratio (OR) 7.91, 95% confidence interval (CI) 2.86, 21.88), conceiving on the second or subsequent covered estrous cycle (OR 1.84, 95% CI 1.22, 2.78) and conceiving multiple conceptuses (OR 1.68, 95% CI 1.02, 2.76) were associated with an increased risk of abortion compared to null parous, first estrous cycle covers and singleton conceptions respectively. Increasing paternal age (OR 0.95, 95% CI 0.90, 0.99) was associated with a decreasing risk of abortion. Mare and farm variance were not significant in the final model, LRT p=0.43. These findings provide evidence-based data to inform Thoroughbred breeding management practices to help mitigate abortion risk.

Effect of advanced parental age on pregnancy outcome and offspring health

PURPOSE

Fertility at advanced age has become increasingly common, but the aging of parents may adversely affect the maturation of gametes and the development of embryos, and therefore the effects of aging are likely to be transmitted to the next generation. This article reviewed the studies in this field in recent years.

METHODS

We searched the relevant literature in recent years with the keywords of "advanced maternal/paternal age" combined with "adverse pregnancy outcome" or "birth defect" in the PubMed database and classified the effects of parental advanced age on pregnancy outcomes and birth defects. Related studies on the effect of advanced age on birth defects were classified as chromosomal abnormalities, neurological and psychiatric disorders, and other systemic diseases. The effect of assisted reproduction technology (ART) on fertility in advanced age was also discussed.

RESULTS

Differences in the definition of the range of advanced age and other confounding factors among studies were excluded, most studies believed that advanced parental age would affect pregnancy outcomes and birth defects in offspring.

CONCLUSION

To some extent, advanced parental age caused adverse pregnancy outcomes and birth defects. The occurrence of these results was related to the molecular genetic changes caused by aging, such as gene mutations, epigenetic variations, etc. Any etiology of adverse pregnancy outcomes and birth defects related to aging might be more than one. The detrimental effect of advanced age can be corrected to some extent by ART.

External validation of a frequently used prediction model for ongoing pregnancy in couples with unexplained recurrent pregnancy loss

STUDY QUESTION

What is the predictive performance of a currently recommended prediction model in an external Dutch cohort of couples with unexplained recurrent pregnancy loss (RPL)?

SUMMARY ANSWER

The model shows poor predictive performance on a new population; it overestimates, predicts too extremely and has a poor discriminative ability.

WHAT IS KNOWN ALREADY

In 50-75% of couples with RPL, no risk factor or cause can be determined and RPL remains unexplained. Clinical management in RPL is primarily focused on providing supportive care, in which counselling on prognosis is a main pillar. A frequently used prediction model for unexplained RPL, developed by Brigham et al. in 1999, estimates the chance of a successful pregnancy based on number of previous pregnancy losses and maternal age. This prediction model has never been externally validated.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study consisted of 739 couples with unexplained RPL who visited the RPL clinic of the Leiden University Medical Centre between 2004 and 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Unexplained RPL was defined as the loss of two or more pregnancies before 24 weeks, without the presence of an identifiable cause for the pregnancy losses, according to the ESHRE guideline. Obstetrical history and maternal age were noted at intake at the RPL clinic. The outcome of the first pregnancy after intake was documented. The performance of Brigham's model was evaluated through calibration and discrimination, in which the predicted pregnancy rates were compared to the observed pregnancy rates.

MAIN RESULTS AND THE ROLE OF CHANCE

The cohort included 739 women with a mean age of 33.1 years (±4.7 years) and with a median of three pregnancy losses at intake (range 2-10). The mean predicted pregnancy success rate was 9.8 percentage points higher in the Brigham model than the observed pregnancy success rate in the dataset (73.9% vs 64.0% (95% CI for the 9.8% difference 6.3-13.3%)). Calibration showed overestimation of the model and too extreme predictions, with a negative calibration intercept of -0.46 (95% CI -0.62 to -0.31) and a calibration slope of 0.42 (95% CI 0.11-0.73). The discriminative ability of the model was very low with a concordance statistic of 0.55 (95% CI 0.51-0.59). Recalibration of the Brigham model hardly improved the c-statistic (0.57; 95% CI 0.53-0.62).

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study in which only the first pregnancy after intake was registered. There was no time frame as inclusion criterium, which is of importance in the counselling of couples with unexplained RPL. Only cases with a known pregnancy outcome were included.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study externally validating the Brigham prognostic model that estimates the chance of a successful pregnancy in couples with unexplained RPL. The results show that the frequently used model overestimates the chances of a successful pregnancy, that predictions are too extreme on both the high and low ends and that they are not much more discriminative than random luck. There is a need for revising the prediction model to estimate the chance of a successful pregnancy in couples with unexplained RPL more accurately.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used and no competing interests were declared.

TRIAL REGISTRATION NUMBER

N/A.

Association between preconception paternal health and pregnancy loss in the USA: an analysis of US claims data

STUDY QUESTION

Is preconception paternal health associated with pregnancy loss?

SUMMARY ANSWER

Poor preconception paternal health is associated with a higher risk of pregnancy loss as confirmed in sensitivity analyses accounting for maternal age and health.

WHAT IS KNOWN ALREADY

Preconception paternal health can negatively impact perinatal outcomes.

STUDY DESIGN, SIZE, DURATION

Retrospective cohort study of US insurance claims database from 2009 to 2016 covering 958 804 pregnancies.

PARTICIPANTS/MATERIALS, SETTING, METHODS

US insurance claims database including women, men and pregnancies within the USA between 2007 and 2016. Paternal preconception health status (e.g. metabolic syndrome diagnoses (MetS), Charlson comorbidity index (CCI) and individual chronic disease diagnoses) was examined in relation to pregnancy loss (e.g. ectopic pregnancy, miscarriage and stillbirth).

MAIN RESULTS AND THE ROLE OF CHANCE

In all, 958 804 pregnancies were analyzed. The average paternal age was 35.3 years (SD 5.3) and maternal age was 33.1 years (SD 4.4). Twenty-two percent of all pregnancies ended in a loss. After adjusting for maternal factors, the risk of pregnancy loss increased with increasing paternal comorbidity. For example, compared to men with no components of MetS, the risk of pregnancy loss increased for men with one (relative risk (RR) 1.10, 95% CI 1.09-1.12), two (RR 1.15, 95% CI 1.13-1.17) or three or more (RR 1.19, 95% CI 1.14-1.24) components. Specifically, less healthy men had a higher risk of siring a pregnancy ending in spontaneous abortion, stillbirth and ectopic pregnancies. Similar patterns remained with other measures of paternal health (e.g. CCI, chronic diseases, etc.). When stratifying by maternal age as well as maternal health, a similar pattern of increasing pregnancy loss risk for men with 1, 2 or 3+ MetS was observed. A statistically significant but weak association between timing of pregnancy loss and paternal health was found.

LIMITATIONS, REASONS FOR CAUTION

Retrospective study design covering only employer insured individuals may limit generalizability.

WIDER IMPLICATIONS OF THE FINDINGS

Optimization of a father's health may improve pregnancy outcomes.

STUDY FUNDING/COMPETING INTERESTS

National Institutes of Health National Center for Advancing Translational Science Clinical and Translational Science Award (UL1 TR001085). M.L.E. is an advisor for Sandstone Diagnostics, Dadi, Hannah and Underdog. No other competing interests were declared.

TRIAL REGISTRATION NUMBER

N/A.

Aging-induced changes in sperm DNA methylation are modified by low dose of perinatal flame retardants

Aims: Paternal age is increasing in developed countries. Understanding of aging-related epigenetic changes in sperm is needed as well as factors that modify such changes. Materials & methods: Young pubertal and mature rats were exposed perinatally to vehicle or environmental xenobiotic 2,2',4,4'-tetrabromodiphenyl ether. Epididymal sperm was reduced representation bisulfite sequenced. Differentially methylated regions (DMRs) were identified via MethPipe. Results: In control animals, 5319 age-dependent DMRs were identified. Age-related DMRs were enriched for embryonic development. In exposed rats, DNA methylation was higher in young and lower in mature animals then in controls. Conclusions: Sperm methylome undergoes significant age-dependent changes, which may represent a causal link between paternal age and offspring phenotype. Environmental xenobiotics can interfere with the natural process of epigenetic aging.

Aging Induces Profound Changes in sncRNA in Rat Sperm and These Changes Are Modified by Perinatal Exposure to Environmental Flame Retardant

Advanced paternal age at fertilization is a risk factor for multiple disorders in offspring and may be linked to age-related epigenetic changes in the father's sperm. An understanding of aging-related epigenetic changes in sperm and environmental factors that modify such changes is needed. Here, we characterize changes in sperm small non-coding RNA (sncRNA) between young pubertal and mature rats. We also analyze the modification of these changes by exposure to environmental xenobiotic 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). sncRNA libraries prepared from epididymal spermatozoa were sequenced and analyzed using DESeq 2. The distribution of small RNA fractions changed with age, with fractions mapping to rRNA and lncRNA decreasing and fractions mapping to tRNA and miRNA increasing. In total, 249 miRNA, 908 piRNA and 227 tRNA-derived RNA were differentially expressed (twofold change, false discovery rate (FDR) p ≤ 0.05) between age groups in control animals. Differentially expressed miRNA and piRNA were enriched for protein-coding targets involved in development and metabolism, while piRNA were enriched for long terminal repeat (LTR) targets. BDE-47 accelerated age-dependent changes in sncRNA in younger animals, decelerated these changes in older animals and increased the variance in expression of all sncRNA. Our results indicate that the natural aging process has profound effects on sperm sncRNA profiles and this effect may be modified by environmental exposure.

Paternal influences from early pregnancy to postpartum years on child development: A longitudinal study

INTRODUCTION

Although an array of maternal and child-centered risks have been researched, considerably less is known about the effects of paternal influences on child's birth outcomes and early development. This longitudinal study thus examined the effects of paternal influences (parental stress, partner support, childcare and nursing, and father-child interaction) from early pregnancy to 2 years postpartum on pregnancy outcomes and toddlerhood development, with a simultaneous consideration of maternal depression.

METHODS

Pregnant women together with their partners were recruited from 2011 to 2016 at five selected hospitals in Taipei, Taiwan. In total, 440 families completed seven assessments from early pregnancy to 2 years postpartum. Self-reported data were analyzed using logistic regression and generalized estimating equation models.

RESULTS

The increment in parental stress from early to late pregnancy was independently and significantly associated with higher risks of low birthweight (adjusted odds ratio [aOR] = 5.3, 95% confidence interval [CI] = 1.0-27.7). In the postpartum years, paternal poorer childcare and nursing (aOR = 1.7, 95% CI = 1.0-3.0) and father-child interaction (aOR = 1.8, 95% CI = 1.2-2.9) were significantly associated with increased risks of child's suspected developmental delay up to 2 years postpartum, particularly among children of nondepressed mothers' children.

LIMITATIONS

Selecting both parents in metropolitan areas with higher socioeconomic status may compromise the generalizability of the study.

CONCLUSIONS

We suggested the essential role of longitudinal paternal influences from early pregnancy on birth outcomes and child's development during infancy and toddlerhood. Maternal depression remains critical to concern.

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.

Genetic and Epigenetic Etiology Underlying Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a pervasive neurodevelopmental disorder characterized by difficulties in social interaction, language development delays, repeated body movements, and markedly deteriorated activities and interests. Environmental factors, such as viral infection, parental age, and zinc deficiency, can be plausible contributors to ASD susceptibility. As ASD is highly heritable, genetic risk factors involved in neurodevelopment, neural communication, and social interaction provide important clues in explaining the etiology of ASD. Accumulated evidence also shows an important role of epigenetic factors, such as DNA methylation, histone modification, and noncoding RNA, in ASD etiology. In this review, we compiled the research published to date and described the genetic and epigenetic epidemiology together with environmental risk factors underlying the etiology of the different phenotypes of ASD.

Paternal age is affected by genetic abnormalities, perinatal complications and mental health of the offspring

Infertility and fecundity problems concern 10-18% of partners in their reproductive years compromising around one million females and males in Poland. Research and analysis of factors that affect male fertility are limited, especially, regarding the age of the father and determining the age at which quality of semen decreases. Age of the father has greater impact than maternal age, on cases of sporadic autosomal dominant congenital diseases such as Apert, Crouzon, Pfeiffer, Noonan and Costello syndromes, multiple endocrine neoplasia (types 2A and 2B) and achondroplasia. However, there are only a few reports taking paternal advanced age into consideration for pre-mature birth, low Apgar scores or admission to a neonatal intensive care department. Paternal age increases the frequency of congenital diseases such as heart malformations as well as oral, palate and lip cleft. Moreover, mental disorders (autism, schizophrenia, bipolar disorder, low IQ level as well as ADHD) also occur more frequently in advanced father's age. Advanced paternal age is defined differently in every research. It depends on disorders in offspring we are talking about. Paternal age has an impact on child's health and development and it is as significant as maternal age, when it comes to reproductive matters.

Advanced paternal age and the risk of spontaneous abortion: an analysis of the combined 2011-2013 and 2013-2015 National Survey of Family Growth

BACKGROUND

Maternal and paternal age at first birth are increasing across the global population. Spontaneous abortion, one of the most common abnormal pregnancy outcomes, is known to occur more frequently with increasing maternal age. However, the relationship of advanced paternal age and spontaneous abortion is poorly understood, and previous results have yielded conflicting results.

OBJECTIVE

To examine the influence of paternal age on the risk of spontaneous abortion among singleton pregnancies conceived without assisted reproductive technologies.

MATERIALS AND METHODS

This was a retrospective, case-control study using combined pregnancy data from the Centers for Disease Control and Prevention's 2011-2013 and 2013-2015 National Survey of Family Growth. Spontaneous, singleton pregnancy data from women aged 15-45 years were analyzed. Ongoing pregnancies, induced abortions, ectopic pregnancies, preterm births, and intrauterine fetal deaths were excluded. Bivariate associations of pregnancy outcome (spontaneous abortion at <20 weeks and ≤12 weeks vs. live birth at ≥37 weeks) and paternal age were determined, along with those of maternal age and selected demographic and pregnancy characteristics. Significant associations were included in a multivariable logistic regression, which accounted for multiple pregnancies derived from the same respondent.

RESULTS

A total of 12,710 pregnancies from 6979 women were analyzed, consisting of 2300 (18.2%) spontaneous abortions and 10,410 (81.8%) term live births. Median maternal and paternal ages were 25 and 28 years, respectively. After adjusting for maternal age, race/ethnicity, socioeconomic status, marital status, and pregnancy intention, pregnancies resulting in spontaneous abortions had 2.05 (95% confidence interval, 1.06-2.20) times the odds of being from a father aged 50 years or older, vs. 25-29 years of age. These relationships remained significant when defining SABs at ≤12 weeks (adjusted odds ratio, 2.30; 95% confidence interval, 1.17-4.52).

CONCLUSION

Paternal age may increase the odds of spontaneous abortion, independent of selected factors, including demographics, pregnancy intention, and maternal age. This association was robust across several gestational age-based definitions of spontaneous abortion, even after adjustment.

Probing disrupted neurodevelopment in autism using human stem cell-derived neurons and organoids: An outlook into future diagnostics and drug development

Autism spectrum disorders (ASDs) represent a spectrum of neurodevelopmental disorders characterized by impaired social interaction, repetitive or restrictive behaviors, and problems with speech. According to a recent report by the Centers for Disease Control and Prevention, one in 68 children in the US is diagnosed with ASDs. Although ASD-related diagnostics and the knowledge of ASD-associated genetic abnormalities have improved in recent years, our understanding of the cellular and molecular pathways disrupted in ASD remains very limited. As a result, no specific therapies or medications are available for individuals with ASDs. In this review, we describe the neurodevelopmental processes that are likely affected in the brains of individuals with ASDs and discuss how patient-specific stem cell-derived neurons and organoids can be used for investigating these processes at the cellular and molecular levels. Finally, we propose a discovery pipeline to be used in the future for identifying the cellular and molecular deficits and developing novel personalized therapies for individuals with idiopathic ASDs.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Parental age and stillbirth: a population-based cohort of nearly 10 million California deliveries from 1991 to 2011

PURPOSE

Parental age at delivery in the United States has been rising. Advanced maternal and paternal ages have been associated with adverse pregnancy outcomes including stillbirth. However, these relationships come from studies that often do not present results for both mother and father concurrently. The purpose of this study was to estimate the risk of stillbirth for maternal and paternal age in the same cohort of deliveries.

METHODS

This is a population-based cohort study of all live birth and stillbirth deliveries in California from 1991 to 2011. The individual associations between maternal and paternal ages and stillbirth were estimated with hazard ratios from Cox proportional hazard models. Age was modeled continuously with restricted cubic splines to account for nonlinear relationships. Mean parental age was used as the referent group.

RESULTS

J-shaped associations between maternal and paternal ages were observed in crude models where older mothers and fathers had the highest hazard ratios for stillbirth. In maternal models, after adjusting for maternal and paternal covariates, young maternal age no longer showed increased hazard ratio for stillbirth, whereas the association with older mothers remained. In adjusted paternal models, the relationship between young paternal age and stillbirth was unchanged while the hazard ratio for older fathers was slightly smaller.

CONCLUSIONS

After adjusting for both parents' age, education, race/ethnicity, along with parity, older mothers and fathers were independently associated with elevated hazard ratios for stillbirth.

The effect of paternal factors on perinatal and paediatric outcomes: a systematic review and meta-analysis

BACKGROUND

Maternal factors, including increasing childbearing age and various life-style factors, are associated with poorer short- and long-term outcomes for children, whereas knowledge of paternal parameters is limited. Recently, increasing paternal age has been associated with adverse obstetric outcomes, birth defects, autism spectrum disorders and schizophrenia in children.

OBJECTIVE AND RATIONALE

The aim of this systematic review is to describe the influence of paternal factors on adverse short- and long-term child outcomes.

SEARCH METHODS

PubMed, Embase and Cochrane databases up to January 2017 were searched. Paternal factors examined included paternal age and life-style factors such as body mass index (BMI), adiposity and cigarette smoking. The outcome variables assessed were short-term outcomes such as preterm birth, low birth weight, small for gestational age (SGA), stillbirth, birth defects and chromosomal anomalies. Long-term outcome variables included mortality, cancers, psychiatric diseases/disorders and metabolic diseases. The systematic review follows PRISMA guidelines. Relevant meta-analyses were performed.

OUTCOMES

The search included 14 371 articles out of which 238 met the inclusion criteria, and 81 were included in quantitative synthesis (meta-analyses). Paternal age and paternal life-style factors have an association with adverse outcome in offspring. This is particularly evident for psychiatric disorders such as autism, autism spectrum disorders and schizophrenia, but an association is also found with stillbirth, any birth defects, orofacial clefts and trisomy 21. Paternal height, but not BMI, is associated with birth weight in offspring while paternal BMI is associated with BMI, weight and/or body fat in childhood. Paternal smoking is found to be associated with an increase in SGA, birth defects such as congenital heart defects, and orofacial clefts, cancers, brain tumours and acute lymphoblastic leukaemia. These associations are significant although moderate in size, with most pooled estimates between 1.05 and 1.5, and none exceeding 2.0.

WIDER IMPLICATIONS

Although the increased risks of adverse outcome in offspring associated with paternal factors and identified in this report represent serious health effects, the magnitude of these effects seems modest.

Mid-life fertility: Challenges & policy planning

This review highlights the challenges, priority areas of research and planning, strategies for regulation of services and the need to develop guidelines and laws for fertility treatments during mid-life. The success rate of all treatments is poor in advanced age women because of declining ovarian reserve and natural fertility. There is often a need of third-party involvement which has its own ethical, legal and medical issues. Welfare of children born to older women and early death of parents are important concerns. Most of the new techniques such as the pre-implantation genetic diagnosis, oocyte augmentation, use of stem cells or artificial gametes, ovarian tissue preservation and ovarian transplantation are directed to improve, preserve or replace the declining ovarian reserve. These techniques are costly and have limited availability, safety and efficacy data. Continued research and policies are required to keep pace with these techniques. The other important issues include the patients' personal autonomy and right of self-determination, welfare of offspring, public vs. private funding for research and development of new technologies vs. indiscriminate use of unproven technology. It is important that mid-life fertility is recognized as a distinct area of human reproduction requiring special considerations.

Association of paternal age with perinatal outcomes between 2007 and 2016 in the United States: population based cohort study

OBJECTIVE

To evaluate the impact of advanced paternal age on maternal and perinatal outcomes in the United States.

DESIGN

Retrospective, population based cohort study.

SETTING

US.

POPULATION

40 529 905 documented live births between 2007 and 2016.

MAIN OUTCOME MEASURES

Primary perinatal outcomes were gestational age, birth weight, Apgar score at five minutes, admission to a neonatal intensive care unit, need for postpartum antibiotics, and seizures. Primary maternal outcomes were gestational diabetes and pre-eclampsia. Secondary outcome was the number of preventable perinatal events.

RESULTS

Higher paternal age was associated with an increased risk of premature birth, low birth weight, and low Apgar score. After adjustment for maternal age, infants born to fathers aged 45 years or older had 14% higher odds of premature birth (odds ratio 1.14, 95% confidence interval 1.13 to 1.15), independent of gestational age, and 18% higher odds of seizures (1.18, 0.97 to 1.44) compared with infants of fathers aged 25 to 34 years. The odds of gestational diabetes was 34% higher (1.34, 1.29 to 1.38) in mothers with the oldest partners. 13.2% (95% confidence interval 12.5% to 13.9%) of premature births and 18.2% (17.5% to 18.9%) of gestational diabetes in births associated with older fathers were estimated to be attributable to advanced paternal age.

CONCLUSIONS

Advanced paternal age is associated with negative effects on both mothers and offspring. Given the relatively low prevalence of advanced paternal age in the US, population level impacts are currently modest. Nevertheless, as advanced paternal age has doubled in the US over the past generation, further investigation is warranted of the impact on birth outcomes and public health.

Reproductive genetics and the aging male

PURPOSE

To examine current evidence of the known effects of advanced paternal age on sperm genetic and epigenetic changes and associated birth defects and diseases in offspring.

METHODS

Review of published PubMed literature.

RESULTS

Advanced paternal age (> 40 years) is associated with accumulated damage to sperm DNA and mitotic and meiotic quality control mechanisms (mismatch repair) during spermatogenesis. This in turn causes well-delineated abnormalities in sperm chromosomes, both numerical and structural, and increased sperm DNA fragmentation (3%/year of age) and single gene mutations (relative risk, RR 10). An increase in related abnormalities in offspring has also been described, including miscarriage (RR 2) and fetal loss (RR 2). There is also a significant increase in rare, single gene disorders (RR 1.3 to 12) and congenital anomalies (RR 1.2) in offspring. Current research also suggests that autism, schizophrenia, and other forms of "psychiatric morbidity" are more likely in offspring (RR 1.5 to 5.7) with advanced paternal age. Genetic defects related to faulty sperm quality control leading to single gene mutations and epigenetic alterations in several genetic pathways have been implicated as root causes.

CONCLUSIONS

Advanced paternal age is associated with increased genetic and epigenetic risk to offspring. However, the precise age at which risk develops and the magnitude of the risk are poorly understood or may have gradual effects. Currently, there are no clinical screenings or diagnostic panels that target disorders associated with advanced paternal age. Concerned couples and care providers should pursue or recommend genetic counseling and prenatal testing regarding specific disorders.

The potential impact of paternal age on risk of asthma in childhood: a study within the Danish National Birth Cohort

BACKGROUND

Advanced paternal age has been associated with offspring morbidity and mortality, possibly due to de novo mutations and epigenetic changes in male germ cells. Epigenetic changes in the cord blood cells have been linked to asthma symptoms in offspring, but the role of paternal age has been less studied.

METHODS

From the Danish National Birth Cohort, 48,785 children who completed the 7-year follow-up were included. Parental reports of physician-diagnosed asthma had been obtained by a posted or web-based questionnaire. Paternal age at delivery was obtained through linkage with maternal civil registration number in the Danish Civil Registration System and classified into four groups: ≤24, 25-34 (reference), 35-39, and >40 years. We calculated the prevalence proportion of asthma and prevalence ratios (PRs) with 95% confidence intervals (CIs) using log-binomial regression, adjusting for paternal smoking, paternal asthma, and paternal socioeconomic status.

RESULTS

At the 7-year follow-up, 5875 children (12%) had physician-diagnosed asthma. The prevalence of asthma in 7-year old children was higher with paternal age of ≤24 (adjusted PR 1.40; 95% CI: 1.26; 1.55) and lower with the paternal age of ≥35 years (adjusted PR 0.84; 95% CI: 0.78; 0.89) compared to the reference group.

CONCLUSIONS

Paternal age of ≥35 years was associated with a lower prevalence of asthma in childhood, and paternal age of ≤24 years with higher prevalence compared with paternal age of 25-34 years. The potential causes of higher asthma prevalence among offspring of young fathers warrant further investigation.

High percentages of embryos with 21, 18 or 13 trisomy are related to advanced paternal age in donor egg cycles

OBJECTIVE

Advanced paternal age is related to poor sperm quality; however, little is known on its effect on aneuploidy embryo rates and, more importantly, on chromosomal abnormalities like trisomy 21, 18 and 13. The objective of this study was to evaluate the effect of advanced paternal age on the trisomy rates of the chromosomes 21, 18 or 13 in embryos obtained from donated oocytes.

METHODS

A total of 378 embryos, obtained from 52 IVF/ICSI cycles with donated oocytes in conjunction with PGD, were allocated according to paternal age in three groups: Group A: ≤39 years (n=115 embryos), Group B: 40-49 years (n=157 embryos) and Group C: ≥50 year (n=106 embryos). Fertilization rates, embryo quality at day 3, blastocysts development, and aneuploidy embryo rates were then compared.

RESULTS

There was no difference in seminal parameters (volume, concentration and motility) in the studied groups. Fertilization rate, percentages of zygotes that underwent cleavage, and good-quality embryos on Day 3 were similar between the three groups evaluated. The group of men ≥50 years had significantly more sperm with damaged DNA, higher global aneuploidy rates, and significantly more embryos with trisomy 21, 18 or 13 compared to the other two evaluated groups (p<0.05).

CONCLUSIONS

Our data shows that advanced paternal age increases global chromosomal abnormalities, and percentages of trisomy 21, 18 or 13 in embryos, and such effect is significantly important as of the age of 50. Embryo genetic screening is highly recommended in patients in which paternal age is ≥50 years old.

From sperm to offspring: Assessing the heritable genetic consequences of paternal smoking and potential public health impacts

Individuals who smoke generally do so with the knowledge of potential consequences to their own health. What is rarely considered are the effects of smoking on their future children. The objective of this work was to review the scientific literature on the effects of paternal smoking on sperm and assess the consequences to offspring. A literature search identified over 200 studies with relevant data in humans and animal models. The available data were reviewed to assess the weight of evidence that tobacco smoke is a human germ cell mutagen and estimate effect sizes. These results were used to model the potential increase in genetic disease burden in offspring caused by paternal smoking, with specific focus on aneuploid syndromes and intellectual disability, and the socioeconomic impacts of such an effect. The review revealed strong evidence that tobacco smoking is associated with impaired male fertility, and increases in DNA damage, aneuploidies, and mutations in sperm. Studies support that these effects are heritable and adversely impact the offspring. Our model estimates that, with even a modest 25% increase in sperm mutation frequency caused by smoke-exposure, for each generation across the global population there will be millions of smoking-induced de novo mutations transmitted from fathers to offspring. Furthermore, paternal smoking is estimated to contribute to 1.3 million extra cases of aneuploid pregnancies per generation. Thus, the available evidence makes a compelling case that tobacco smoke is a human germ cell mutagen with serious public health and socio-economic implications. Increased public education should be encouraged to promote abstinence from smoking, well in advance of reproduction, to minimize the transmission of harmful mutations to the next-generation.

Advanced paternal age and stillbirth rate: a nationwide register-based cohort study of 944,031 pregnancies in Denmark

Advanced paternal age has been associated with a variety of rare conditions and diseases of great public health impact. An increased number of de novo point mutations in sperm with increasing age have been suggested as a mechanism, which would likely also affect fetal viability. We examined the association between paternal age and stillbirth rate in a large nationwide cohort. We identified all pregnancies in Denmark from 1994 to 2010 carried to a gestational age of at least 22 completed weeks (n = 944,031) as registered in national registers and linked to individual register data about the parents. The hazard ratio of stillbirth according to paternal age was estimated, adjusted for maternal age in 1-year categories, year of outcome, and additionally parental educational levels. The relative rate of stillbirth (n = 4946) according to paternal age was found to be J-shaped with the highest hazard ratio for fathers aged more than 40 years when paternal age was modelled using restricted cubic splines. When modelled categorically, the adjusted hazard ratios of stillbirth were as follows: <25, 1.16 (95% confidence interval, CI 1.01-1.34); 25-29, 1.03 (95% CI 0.95-1.11); 35-39, 1.16 (95% CI 1.07-1.26); 40-44, 1.41 (95% CI 1.26-1.59); 45-49, 1.20 (95% CI 0.97-1.49); 50+, 1.58 (95% CI 1.18-2.11), compared with fathers aged 30-34 years. These estimates attenuated slightly when further adjusted for parental education. Our study showed that paternal age was associated with the relative rate of stillbirth in a J-shaped manner with the highest hazard ratios among fathers aged more than 40 years.

Younger or older parental age and risk of suicidality, premature death, psychiatric illness, and criminality in offspring

BACKGROUND

Younger or older parental age has been linked with a range of adverse offspring endpoints. We investigated associations between parental age and nine adverse offspring outcomes in three correlated domains: (i) Premature death: suicide, unnatural death, natural death; (ii) Psychiatric morbidity: any mental illness, suicide attempt, substance misuse; (iii) Criminality: violent offending, imprisonment, driving whilst intoxicated.

METHODS

Persons born in Denmark 1966-1996 were followed from their 15th until 40th birthday or December 2011 (N=1,793,681). Incidence rate ratios were estimated.

RESULTS

Offspring of teenage mothers had the greatest risks for all nine adverse outcomes, especially for imprisonment, violent offending, substance misuse, and attempted suicide. Teenage fatherhood was also associated with elevated risks for offspring adverse psychiatric and criminality outcomes, but not premature mortality (at ages 15-39 years). For the psychiatric and criminality outcomes there was a U-shape trend linked with paternal age, but risks for premature mortality tended to increase with rising paternal age. On the contrary, maternal age 30 years and over was not linked with raised risks for any of the outcomes examined.

LIMITATIONS

Parental links are based on legal and not biological relationships.

CONCLUSIONS

The substantially elevated risks linked with teenage motherhood for a variety of poor offspring outcomes is a concern for clinicians and policymakers. The associations observed across such a wide array of adverse outcomes also suggest that multiple causal mechanisms may be implicated.

Is advanced paternal age a health risk for the offspring?

In this article we review the epidemiologic evidence for adverse health effects in offspring of fathers of advanced age. First the evidence regarding fetal survival is addressed, and afterward we review the evidence regarding morbidity in children with older fathers. The adverse conditions most consistently associated with increased paternal age are stillbirths, musculo-skeletal syndromes, cleft palate, acute lymphoblastic leukemia and retinoblastoma, and neurodevelopmental disorders in the autism spectrum and schizophrenia. Finally, we consider the public health impact of the increasing paternal age. We conclude that the adverse health effects in children that might be caused by the present increase in paternal age are severe but quantitatively of minor importance. However, identification of morbidities that are more frequent in offspring of older fathers, after having taken any maternal age effects and other confounding into account, may lead to a better understanding of the pathogenesis behind such conditions.

Advanced parental age and autism risk in children: a systematic review and meta-analysis

OBJECTIVE

Advanced parental age has raised additional concern as a risk factor of autism. We conducted a meta-analysis of observational studies investigating the association between advanced parental age and risk of autism.

METHOD

PubMed, EMBASE, and Web of Science were searched for reports published up to November 11, 2015. Risk estimates from individual studies were pooled using random-effects models.

RESULTS

Twenty-seven studies were included in the meta-analysis. Compared with the reference points, the lowest parental age category was associated with a reduced risk of autism in the offspring, with adjusted odds ratios (ORs) 0.89 (95% confidence intervals [CIs] 0.75-1.06) and 0.81 (95% CI 0.73-0.89) for mother and father, respectively, and the highest parental age category was associated with an increased risk of autism in the offspring, with adjusted ORs 1.41 (95% CI 1.29-1.55) and 1.55 (95% CI 1.39-1.73) for mother and father respectively. Dose-response meta-analysis indicated that an increase of 10 years in maternal and paternal age was associated with an 18% and 21% higher risk of autism.

CONCLUSION

Advanced parental age was associated with an increased risk of autism in the offspring. More mechanistic studies are needed to further explain this positive association.

Does age of the sperm donor influence live birth outcome in assisted reproduction?

STUDY QUESTION

Does age of the sperm donor have an effect on reproductive outcomes (live birth rate and miscarriage occurrence) of donor insemination or in vitro fertilization treatment using donated sperm?

SUMMARY ANSWER

Live birth and miscarriage occurrence in assisted reproduction treatment using donor sperms was not found to be affected by the age of sperm donors up to 45 years old.

WHAT IS ALREADY KNOWN

Literature on the effect of sperm donor age on outcome of medically assisted reproduction is scarce. Most researchers agree that semen parameters deteriorate with increasing paternal age. However, there is no substantial evidence to suggest that this deterioration adversely affects the reproductive outcomes in couples undergoing medically assisted reproduction.

STUDY DESIGN, SIZE, DURATION

This retrospective cohort study analysed 46 078 first donor insemination treatments and fresh in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles using donated sperm from 1991 to 2012.

PARTICIPANTS/ DURATION/METHODS

The first fresh donor insemination and IVF/ICSI treatment cycles (46 078 treatment cycles) using donated sperm from the long-term anonymized data registry from 1991 to 2012 of the HFEA, the UK regulator, were analysed by the binary logistic modelling technique for association between sperm donor age and reproductive outcomes (live birth occurrence and miscarriage occurrence). The statistical package SPSS (version 21) was used for analysis and results were considered to be statistically significant if the P-value was <0.05.

MAIN RESULTS AND THE ROLE OF CHANCE

Of 46 078 women, 84.6% (N = 38 974) underwent donor insemination treatment and the remainder, 15.4% (N = 7104), had IVF/ICSI treatment with donor sperm. The live birth occurrence decreased with increasing female age in both treatment groups; In the donor insemination treatment group, it was 11.1% in 18-34 year old women, 8.3% in 35-37 year old women and 4.7% in 38-50 year old women. The corresponding figures in the IVF/ICSI treatment group were 28.9, 22.0 and 12.9% respectively. In each of these subgroups, no evidence of declining likelihood of live birth with increasing sperm donor age was found (P > 0.05). The miscarriage occurrence (i.e. number of miscarriages per 100 women commencing treatment) was 1.3% in 18-34 year old women, 1.9% in 35-37 year old women and 1.9% in 38-50 year old women undergoing donor insemination treatment. In the sperm donation IVF/ICSI treatment group, these figures were 5.7, 8.4 and 6.8% respectively. The results were not suggestive of any unfavourable effect of advancing sperm donor age on the odds of miscarriage occurrence (P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

As sperm donors are a select population based on good semen indices, the generalization of results to the paternal population at large may not be possible. Although the study subgroups were controlled for female age, treatment modality and effect of previous treatment cycles, adjustments for certain potential compounding factors, such as smoking status, BMI of women and stimulation protocol used in IVF/ICSI treatment cycles, were not possible.

WIDER IMPLICATIONS OF THE FINDINGS

Live birth and miscarriage occurrence following assisted reproduction weren't adversely affected by increasing sperm donor age up to 45 years. In view of the increasing demand for donor sperm, further studies may be required to ascertain the safe upper age limit for sperm donors.

STUDY FUNDING/COMPETING INTERESTS

No funding was received from any individual or funding agency. NG was on a Commonwealth Scholarship for the duration of the study. The authors do not have any conflicts of interest to declare.

Advanced Paternal Age and Risk of Musculoskeletal Congenital Anomalies in Offspring

OBJECTIVE

Previous research suggests that advanced paternal age increases the risk of musculoskeletal congenital anomalies (CAs) in offspring, but findings are inconsistent. This study aims to investigate the risk of musculoskeletal CAs according to paternal age at birth in an unselected population covering cohort of children.

STUDY DESIGN

A register-based prospective study of 1,605,885 children born in Denmark, 1978-2004, using information from record-linked health and administrative registers. The association between paternal age and overall musculoskeletal CAs, limb anomalies, craniosynostosis, skeletal dysplasias, syndromic musculoskeletal CAs, and other musculoskeletal CAs were investigated by multiple logistic regression analysis.

RESULTS

For overall musculoskeletal CAs, a slightly higher risk per 10-year increase in paternal age was found (odds ratio [OR] = 1.06 [95% CI: 1.01-1.11; where CI is confidence interval]). A 26% (95% CI: 2-56%) excess risk was found for fathers aged 50+ years compared to fathers aged 30-34 years. For syndromic musculoskeletal CAs, excess risks were found for fathers aged 40+ years, compared to fathers aged 30-34 years (40-44: OR = 1.38 [95% CI: 1.01-1.88], 45-49: OR = 1.45 [95% CI: 0.89-2.34], 50+: OR = 1.42 [95% CI: 0.73-2.79]). The risks in all other subgroups of musculoskeletal CAs were increased for fathers aged 50+ years.

CONCLUSIONS

A slightly higher risk for overall musculoskeletal CAs in offspring was found with increasing paternal age, mainly due to an excess risk of syndromic musculoskeletal CAs for fathers aged 40+ years. While associations between paternal age 50+ years and increased risk of all subtypes of musculoskeletal CAs were indicated, advanced paternal age likely plays a minor role in the etiology of these anomalies.

Effects of increased paternal age on sperm quality, reproductive outcome and associated epigenetic risks to offspring

Over the last decade, there has been a significant increase in average paternal age when the first child is conceived, either due to increased life expectancy, widespread use of contraception, late marriages and other factors. While the effect of maternal ageing on fertilization and reproduction is well known and several studies have shown that women over 35 years have a higher risk of infertility, pregnancy complications, spontaneous abortion, congenital anomalies, and perinatal complications. The effect of paternal age on semen quality and reproductive function is controversial for several reasons. First, there is no universal definition for advanced paternal ageing. Secondly, the literature is full of studies with conflicting results, especially for the most common parameters tested. Advancing paternal age also has been associated with increased risk of genetic disease. Our exhaustive literature review has demonstrated negative effects on sperm quality and testicular functions with increasing paternal age. Epigenetics changes, DNA mutations along with chromosomal aneuploidies have been associated with increasing paternal age. In addition to increased risk of male infertility, paternal age has also been demonstrated to impact reproductive and fertility outcomes including a decrease in IVF/ICSI success rate and increasing rate of preterm birth. Increasing paternal age has shown to increase the incidence of different types of disorders like autism, schizophrenia, bipolar disorders, and childhood leukemia in the progeny. It is thereby essential to educate the infertile couples on the disturbing links between increased paternal age and rising disorders in their offspring, to better counsel them during their reproductive years.

Male biological clock: a critical analysis of advanced paternal age

Extensive research defines the impact of advanced maternal age on couples' fecundity and reproductive outcomes, but significantly less research has been focused on understanding the impact of advanced paternal age. Yet it is increasingly common for couples at advanced ages to conceive children. Limited research suggests that the importance of paternal age is significantly less than that of maternal age, but advanced age of the father is implicated in a variety of conditions affecting the offspring. This review examines three aspects of advanced paternal age: the potential problems with conception and pregnancy that couples with advanced paternal age may encounter, the concept of discussing a limit to paternal age in a clinical setting, and the risks of diseases associated with advanced paternal age. As paternal age increases, it presents no absolute barrier to conception, but it does present greater risks and complications. The current body of knowledge does not justify dissuading older men from trying to initiate a pregnancy, but the medical community must do a better job of communicating to couples the current understanding of the risks of conception with advanced paternal age.

Consistent age-dependent declines in human semen quality: a systematic review and meta-analysis

Reduced fertility typically occurs among women in their late 30s, but increasing evidence indicates that advanced paternal age is associated with changes in reproduction as well. Numerous studies have investigated age-based declines in semen traits, but the impact of paternal age on semen parameter values remains inconclusive. Using data from 90 studies (93,839 subjects), we conducted a systematic review and meta-analysis to quantify the effect of male age on seven ejaculate traits (semen volume, sperm concentration, total sperm count, morphology, total motility, progressive motility and DNA fragmentation). Age-associated declines in semen volume, percentage motility, progressive motility, normal morphology and unfragmented cells were statistically significant and results generally seemed to be robust against confounding factors. Unexpectedly, sperm concentration did not decline with increasing male age, even though we found that sperm concentration declined over time. Our findings indicate that male age needs more recognition as a potential contributor to the negative pregnancy outcomes and reduced offspring health associated with delayed first reproduction. We suggest that greater focus on collection of DNA fragmentation and progressive motility in a clinical setting may lead to better patient outcomes during fertility treatments of aging couples.

Delayed fatherhood

Birth data from developed countries indicates that the average paternal age is increasing. As the trend to older fatherhood has become established, concerns have been raised that this may be linked to adverse outcomes, such as pregnancy complications, congenital anomalies, and long-term health implications for the child. Since the sperm of older fathers may be impaired due to the general effects of ageing, their offspring may be at risk due to defects in sperm quality at conception. A literature search was performed to identify pregnancy complications, fetal anomalies and health issues for the child when the father is in an older age bracket. Evidence for impairment in the sperm and genetic material of older fathers was reviewed. With an older father, there is evidence of an increase in stillbirths and a slightly increased risk of autism, bipolar disorder and schizophrenia in the offspring later in life. The increased risk of achondroplasia has long been recognised. For the mother, there is an increased rate of Caesarean section. Investigations of other possible adverse outcomes have produced mixed findings. Further robust and longitudinal studies are needed to clarify these issues.

Risk factors for early miscarriage among Chinese: a hospital-based case-control study

OBJECTIVE

To investigate the risk factors for early miscarriage among Chinese women.

DESIGN

Hospital-based matched case-control study.

SETTING

Academic medical center and maternal health hospital.

PATIENT(S)

620 women with early miscarriage (less than 13 weeks of gestation) and 1,240 normal pregnant women.

INTERVENTION(S)

Face-to-face questionnaire.

MAIN OUTCOME MEASURE(S)

Multivariable conditional odds ratio (OR) and 95% confidence interval (CI) to measure risk factors.

RESULT(S)

After adjustment for confounding factors, the following were independently associated with increased risk: history of miscarriage, repeated induced abortion, working night shifts, and frequent staying up late. Vitamin supplementation and regular physical activity reduced the risk of miscarriage. We did not find paternal age, alcohol consumption, or smoking status to be linked with early miscarriage.

CONCLUSION(S)

Our findings suggest that a healthy diet, regular physical activity, and planned pregnancy may be advantageous for women in pre-pregnancy or early pregnancy. Induced abortion, working night shifts, and frequent staying up late were associated with an increased risk of miscarriage. Further work in larger populations is warranted.

Fathers matter: the role of paternal age in infant mortality

Infant mortality is the most widely used indicator of a nation's health status and is associated with a plethora of maternal and socioeconomic factors. Although the association between young and old maternal age and the risk of infant mortality is well established, the link between paternal age and birth outcomes has received far less attention. This study seeks to examine the added impact of paternal age on infant mortality, above and beyond that of maternal age among married couples. Using the 2002 linked birth and infant death data set (N = 63,754), hazard odds ratios for the association between combined adolescent and adult maternal and paternal age and the risk of infant mortality were estimated. Maternal demographic characteristics, such as education and race/ethnicity were controlled. The findings indicate that, independent of maternal education and race/ethnicity, adolescent father adds additional risk, above and beyond that of maternal age, only when the mother is older (21-45 years; hazard ratio = 2.7). This study highlights that for married couples, adolescent fathers add to the risk of infant mortality when the mothers are older, providing insight into the role of paternal age in infant mortality. Implications for additional research are discussed.

Paternal age, placental weight and placental to birthweight ratio: a population-based study of 590,835 pregnancies

STUDY QUESTION

Is the age of the father associated with placental weight or the ratio of placental weight to birthweight?

SUMMARY ANSWER

Placental weight and placental to birthweight ratio increased according to increasing paternal age, also after adjustment for maternal age.

WHAT IS KNOWN ALREADY

High paternal age and also high placental to birthweight ratio have been associated with adverse pregnancy outcome.

STUDY DESIGN, SIZE AND DURATION

We performed a population-based study and included all singleton births after 22 weeks of gestation in the Medical Birth Registry of Norway (n = 590,835) during the years 1999-2009.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We compared mean placental weight and placental to birthweight ratio between paternal age groups. The association of paternal age with placental weight was estimated by linear regression analyses, and adjustments were made for maternal age, birthweight, parity, offspring sex, gestational age at birth, maternal smoking, pre-eclampsia, maternal diabetes mellitus and pregnancy after assisted reproductive technology (ART).

MAIN RESULTS AND THE ROLE OF CHANCE

In pregnancies with fathers aged 20-24 years old, the mean placental weight was 656.2 g [standard deviation (SD) 142.8], whereas it was 677.8 g (SD 160.0) in pregnancies with fathers aged 50 years or older (P < 0.001). The mean offspring birthweight in pregnancies with fathers aged 20-24 year old was 3465.0 g (SD 583.8), and it was 3498.9 g (SD 621.8) when the father was 50 years or older (P < 0.001). The placental to birthweight ratio in the corresponding paternal age groups were 0.191 (SD 0.039) and 0.196 (SD 0.044) (P < 0.001). In multivariable linear regression analysis the placentas in pregnancies fathered by a man of 50 years or older were estimated to weigh 13.99 g [95% confidence interval (CI) 10.88-17.10] more than in pregnancies with a 20-24-year-old father (P < 0.001) after adjustment for maternal age, birthweight, parity, offspring sex, gestational age at birth, maternal smoking, pre-eclampsia, maternal diabetes mellitus and pregnancy after ART.

LIMITATIONS, REASONS FOR CAUTION

Paternal age explains only a small proportion of the total variation in placental weight.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings may increase the understanding of the father's role in human pregnancy.

STUDY FUNDING/ COMPETING INTEREST(S)

Norwegian Resource Centre for Women's Health, Norway. No conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.