Men's body mass index in relation to embryo quality and clinical outcomes in couples undergoing in vitro fertilization

A ripple effect? The impact of obesity on sperm quality and function

Infertility affects approximately 15% of couples trying to conceive. Male-related causes account for roughly 50% of cases, with obesity emerging as a possible significant factor. Obesity, defined as a body mass index of 30.0 or higher, has become a widespread epidemic associated with numerous health issues, including a decrease of fertility. This review discusses the relationship between obesity and male infertility, particularly focusing on sperm quality and function. An overview of the literature suggests that obesity may influence the male reproductive system via disruptions in hormonal profiles, oxidative stress, and inflammation, leading to changes in sperm parameters. Several studies have discussed if obesity causes a decrease in sperm concentration, motility, and normal morphology, so far without a consensus being reached. However, available evidence suggests an impairment of sperm function in obese men, due to an increase in DNA damage and oxidative stress, impaired mitochondrial function and acrosome reaction in response to progesterone. Finally, the relationship between obesity and assisted reproductive technologies outcomes remains debatable, with conflicting evidence regarding the influence on fertilisation, pregnancy, and live birth rates. Therefore, the actual impact of obesity on human spermatozoa still needs to be clarified, due to the multiple factors potentially in play.

Infertility Improvement after Medical Weight Loss in Women and Men: A Review of the Literature

Infertility is a modern health problem. Obesity is another expanding health issue associated with chronic diseases among which infertility is also included. This review will focus on the effects of weight loss by medical therapy on fertility regarding reproductive hormonal profile, ovulation rates, time to pregnancy, implantation rates, pregnancy rates, normal embryo development, and live birth rates. We comprised medicine already used for weight loss, such as orlistat and metformin, and emerging medical treatments, such as Glucagon-Like Peptide-1 receptor agonists (GLP-1 RA). Their use is not recommended during a planned pregnancy, and they should be discontinued in such cases. The main outcomes of this literature review are the following: modest weight loss after medication and the duration of the treatment are important factors for fertility improvement. The fecundity outcomes upon which medical-induced weight loss provides significant results are the female reproductive hormonal profile, menstrual cyclicity, ovulation and conception rates, and pregnancy rates. Regarding the male reproductive system, the fertility outcomes that feature significant alterations after medically induced weight loss are as follows: the male reproductive hormonal profile, sperm motility, movement and morphology, weight of reproductive organs, and sexual function. The newer promising GLP-1 RAs show expectations regarding fertility improvement, as they have evidenced encouraging effects on improving ovulation rates and regulating the menstrual cycle. However, more human studies are needed to confirm this. Future research should aim to provide answers about whether medical weight loss therapies affect fertility indirectly through weight loss or by a possible direct action on the reproductive system.

Effect of Paternal Body Mass Index on In Vitro Fertilization and Neonatal Outcomes among Oligozoospermia and Asthenospermia Patients

PURPOSE

Male overweight and obesity could affect sperm quality and reproductive health. However, the impact of body mass index (BMI) on assisted reproductive technology (ART) outcomes in oligospermia and/or asthenospermia patients is yet lacking. This study aims to assess the impact of paternal BMI on ART and neonatal outcomes among oligozoospermia and/or asthenospermia patients undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

MATERIALS AND METHODS

In this study, 2,075 couples undergoing their first fresh embryo transfer between January 2015 and June 2022 were recruited. Following the World Health Organization's (WHO's) categories, couples were stratified into three cohorts based on paternal BMI: normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obese (≥30.0 kg/m²). Modified Poisson regression models were used to assess the associations of paternal BMI with fertilization, in vitro embryonic development, and pregnancy outcomes. Logistic regression models were performed to investigate the associations of paternal BMI with pregnancy loss and neonatal outcomes. Furthermore, stratified analyses were performed based on fertilization methods, male infertility cause, and maternal BMI.

RESULTS

Higher paternal BMI is associated with a lower likelihood of achieving normal fertilized (p-trend=0.002), Day 3 transferable (p-trend=0.007), and high-quality embryos (p-trend=0.046) in IVF cycles, rather than in ICSI cycles. Paternal BMI of oligospermia or asthenospermia was negatively correlated with day 3 transferable (p-trend=0.013 and 0.030) and high-quality embryos (p-trend=0.024 and 0.027). Moreover, for neonatal outcomes, paternal BMI was positively associated with macrosomia (p-trend=0.019), large for gestational age (LGA) (p-trend=0.031), and very LGA (p-trend=0.045).

CONCLUSIONS

Our data suggested that higher paternal BMI was associated with fetal overgrowth, reduced fertilization, and embryonic development potential. Among males with oligospermia and/or asthenospermia, the impact of overweight and obesity on the choice of fertilization method and the long-term effects on their offspring need to be further investigated.

Obesity and male infertility

The worldwide prevalence of obesity is increasing among both sexes, with associated impacts on chronic health and medical comorbidities. Similarly, the effects of obesity on reproductive health are increasingly being recognized. Adiposity is associated with reduced fertility in men, with a complex and multifactorial etiology. The reported effects of obesity on semen parameters and impaired fertility are contrasting, with some studies showing a clear reduction in reproductive outcomes associated with increased body mass index, while others do not show such impacts. These controversies may be due to the complex pathophysiology and interplay between gonadotropins and end organs, as well as genetic and epigenetic changes and oxidative stress on male fertility and function. These different aspects have led to heterogeneous participants in studies and varying implications for assisted reproductive outcomes as well as offspring health. Treatment modalities to manage obesity include lifestyle, medical, and surgical options, with emerging and effective medical treatments showing promise in reproductive outcomes.

The effect of obesity on human reproductive health and foetal life

Obesity in both women and men is regarded as one of the many factors that may contribute to impaired reproductive health. Obesity can be accompanied by several neuroendocrine and ovarian dysfunctions, including chronic oligo/anovulation, menstrual irregularities, subfertility, and the increased risk of pregnancy in women. Insulin resistance, elevated triglyceride and fatty acid levels, and the secretion of adipocytokines caused by the excessive accumulation of adipose tissue associated with obesity adversely affect reproductive functions. Alterations in sperm quality and motility and hormone levels related to a rise in body mass index (BMI) may predispose men to infertility. The mechanisms of action of obesity on male infertility include endocrinopathy, erectile dysfunction, epididymitis, increased leptin and adipocytes, increased aromatase, inflammatory cytokines secreted by fat tissue, and sperm DNA fragmentation. This study reports that an increased BMI may lead to low semen quality, poor sperm motility, and reduced fertilization rates in men as well as anovulation, pregnancy loss, diminished pregnancy, and low live birth rates in women. Having optimal weight with balanced nutrition enables one to maintain a continuity of reproductive health throughout the entire life cycle, which is extremely important in terms of having a healthy embryo, including pre-foetal life, in the continuity of pregnancy and having a live birth.

The effect of maternal body mass index on embryo division timings in women undergoing in vitro fertilization

Objective

To measure the impact of maternal body mass index (BMI) on the morphokinetics of embryo development as monitored by a time-lapse system.

Design

A retrospective chart review of in vitro fertilization (IVF) cycles from September 2016 to January 2019.

Setting

Academic IVF practice.

Patients

Patients <age 38 years undergoing IVF with their own gametes.

Interventions

Not applicable.

Main outcome measures

The primary outcome was to compare embryo division timings between morbidly obese, obese, overweight, and normal-weight patients. A multilevel mixed effects model was performed to investigate the relationships between BMI categories and embryo division timings. Log or square transformation were used to improve fit.

Results

A total of 366 patients met inclusion criteria, yielding 4,475 embryos: 1,948 embryos from 162 normal-weight women (BMI 18.5-24.9), 1,242 embryos from 96 overweight women (BMI 25.0-29.9), 1,119 embryos from 91 obese women (BMI 30.0-39.9), and 166 embryos from 17 morbidly obese women (BMI ≥40). There were no differences in age, Antimüllerian hormone, or IVF cycle outcomes among the different BMI categories. When comparing embryo division timings based on BMI, controlling for covariates, embryos from obese patients had a shorter time to division to 2 cell embryo (T2) than normal-weight patients. When analyzing BMI as a continuous variable, there was no significant relationship between BMI and embryo division timing.

Conclusions

Early embryo divisions were accelerated in only certain categories of obesity. This suggests a more complex mechanism for the effect of obesity on embryo development that may not be perceptible through the assessment of cell division timing events.

Impact of paternal body mass index on assisted reproduction treatment outcomes: An updated systematic review and meta-analysis

AIM

The aim was to provide updated evidence on the association of male body mass index (BMI) with outcomes of assisted reproduction technology (ART).

METHODS

PubMed, Embase, and Scopus databases were systematically searched. The review included observational studies in patients undergoing ART, that is, either in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and compared rate of clinical pregnancy and live birth based on different categories of male BMI. Quality of the pooled findings was assessed using the GRADE criteria.

RESULTS

A total of 19 studies were included in the review. Among subjects undergoing IVF, there were no significant differences in the rates of clinical pregnancy among overweight (odds ratio [OR] 1.38, 95% confidence interval [CI]: 0.65, 2.96) and obese (OR 1.86, 95% CI: 0.75, 4.58) BMI, compared to normal male BMI. Similarly, there were no significant differences in the rates of live birth among overweight (OR 1.04, 95% CI: 0.97, 1.13) and obese BMI (OR 0.90, 95% CI: 0.69, 1.18) when compared to males with normal BMI. Further, among those undergoing ICSI, there were no significant differences in the odds of clinical pregnancy among overweight (OR 0.98, 95% CI: 0.73, 1.33) and obese (OR 0.89, 95% CI: 0.62, 1.29). The odds of live births among overweight (OR 0.97, 95% CI: 0.89, 1.05) and obese (OR 0.95, 95% CI: 0.84, 1.07) male BMI were statistically similar to males with normal BMI undergoing ICSI.

CONCLUSIONS

The low to very low-quality findings suggest no significant association of overweight and obese BMI with clinical pregnancy and live birth rates among couples undergoing either IVF or ICSI.

Pregnancy Achievement by Medical Assisted Reproduction Is Correlated to the G Protein-Coupled Receptor 30 mRNA Abundance in Human Spermatozoa

Estrogens, specifically 17β-estradiol (E2), play an important role in male health, including male fertility. The G protein-coupled receptor for estrogen 30 (GPR30) is essential for mediating the rapid non-genomic effects of E2 on a variety of testicular cells, including spermatozoa, although its molecular effects remain largely unknown. In this work, we hypothesized that the GPR30 mRNA abundance in spermatozoa could be correlated to sperm quality. Sperm GPR30 mRNA could also be carried into the oocyte, potentially impacting embryo development and the success of a pregnancy. For this study, 81 sperm samples were collected from couples seeking fertility treatment and undergoing medically assisted reproduction treatments (ART), following the World Health Organization guidelines. GPR30 mRNA abundance in spermatozoa was assessed with a quantitative polymerase chain reaction. The resulting data show that there is no correlation between the abundance of the GPR30 transcript with paternal BMI, age, or sperm quality parameters. Interestingly, we observed that higher levels of GPR30 mRNA abundance in spermatozoa were related to the achievement of biochemical pregnancy and clinical pregnancy (p < 0.05) by couples undergoing treatment. These results highlight the role of the sperm’s RNA cargo in offspring development, suggesting that spermatozoa mRNA content can influence ART success.

Protamines and DNA integrity as a biomarkers of sperm quality and assisted conception outcome

Present research aim was to identify functional tests in semen associated with DNA damage and chromatin maturity (protamination) which predict the outcome in assisted reproduction. Couples were grouped according to male partner semen parameters, into normozoospermia (NZs), severe male factor (SMF) and mild male factor (MMF). DNA fragmentation index (DFI) in spermatozoa was analysed by sperms chromatin dispersion (SCD), sperm chromatin structure assay (SCSA) and acridine orange testing (AOT). Chromomycin A3 (CMA3) and toluidine blue (TB) staining to measure sperm chromatin maturity (CM). DFI and chromatin decondensation were significantly lower in N compared to male factor categories (MMF and SMF). Aneuploidy embryos were significantly higher in couples with male factor infertility (MMF and SMF). A positive correlation was observed between fertilization rate (FR) and live birth rate (LBR) with sperm concentration, motility, vitality, normal sperm morphology and negative correlation between sperm DFI and sperm CM. No correlation was observed between embryo aneuploidy and sperm DFI or CM. Lower percentage of spermatozoa chromatin integrity are associated with low fertilization and live birth rate. Male factor infertility, due to impaired semen parameters and chromatin defects could be regarded in future as an indication of IVF/ICSI, and predictor of assisted reproductive techniques outcome.

Is a Ketogenic Diet Superior to a High-Fat, High-Cholesterol Diet Regarding Testicular Function and Spermatogenesis?

The study aimed to determine effects of a ketogenic diet on metabolic dysfunction, testicular antioxidant capacity, apoptosis, inflammation, and spermatogenesis in a high-fat and high-cholesterol diet-induced obese mice model. Forty-two male C57BL/6 mice were fed either a normal diet (NC group) or a high-fat and high-cholesterol (HFC) diet (HFC group) for 16 weeks, and mice from the HFC group were later randomly divided into two groups: the first were maintained on the original HFC diet, and the second were fed a medium-chain triacylglycerol (MCT)-based ketogenic diet for 8 weeks (KD group). A poor semen quality was observed in the HFC group, but this was eliminated by the ketogenic diet. Both the HFC and KD groups exhibited enhanced apoptosis protein expressions in testis tissue, including caspase 3 and cleaved PARP, and higher inflammation protein expressions, including TNF-α and NF-κB. However, the KD group exhibited a statistically-significant reduction in lipid peroxidation and an increased glutathione peroxidase level as compared with the HFC group. The HFC diet induced obesity in mice, which developed body weight gain, abnormal relative organ weights, metabolic dysfunction, and liver injury. Overall, the results showed that a ketogenic diet attenuated oxidative stress and improved the semen quality reduced by the HFC diet.

Men's Sleep Quality and Assisted Reproductive Technology Outcomes in Couples Referred to a Fertility Clinic: A Chinese Cohort Study

BACKGROUND

Poor sleep quality has been linked to lower semen quality, but it is unclear whether this result in decreased fertility. To address this question, we retrospectively evaluated the relationship between men's sleep quality and treatment outcomes in subfertile couples receiving assisted reproductive technology (ART).

PATIENT ENROLLMENT AND METHODS

From September 2017 to November 2019, 282 subfertile couples referred to a Chinese fertility clinic and eligible for ART procedures were enrolled in our study. Sociodemographic characteristics, life habits, and sleep habits in the year prior to ART were recorded. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI). We first divided the patients into two groups based on sleep quality (good sleep: PSQI < 5 and poor sleep: PSQI ≥ 5). Then, the ART outcomes (fertilization rate, good quality embryo rate, implantation rate, positive pregnancy rate, clinical pregnancy rate, live birth rate, miscarriage rate, and birth weight) of each group were analyzed. Finally, multivariate linear and logistic regression analysis were used to examine the relationship between sleep quality (discrete variable or dichotomous variable) and ART outcomes.

RESULTS

The participants in the poor sleep group showed a lower fertilization rate of 60.13% (543/903) when compared with 67.36% for the good sleep group (902/1339), P < 0.001. The global PSQI score had a significant influence on birth weight (β, -63.81; 95% CI, -119.91- -8.52; P = 0.047), and live birth rate (OR, 0.88; 95% CI, 0.78- 0.99; P = 0.047) after adjusting for the interfering factors. Men's sleep quality was unrelated to good quality embryos rate, implantation rate, positive pregnancy rate, clinical pregnancy rate, or miscarriage rate.

CONCLUSION

Men's sleep quality was positively associated with fertilization rate, birth weight, and live birth rate among couples undergoing ART.

Obesity and reproduction: a committee opinion

The purpose of this American Society for Reproductive Medicine Practice Committee report is to provide clinicians with principles and strategies for the evaluation and treatment of couples with infertility associated with obesity. This revised document replaces the Practice Committee document titled "Obesity and reproduction: an educational bulletin" last published in 2015 (Fertil Steril 2015;104:1116-26).

Low protein diet and methyl-donor supplements modify testicular physiology in mice

The link between male diet and sperm quality has received significant investigation. However, the impact diet and dietary supplements have on the testicular environment has been examined to a lesser extent. Here, we establish the impact of a sub-optimal low protein diet (LPD) on testicular morphology, apoptosis and serum fatty acid profiles. Furthermore, we define whether supplementing a LPD with specific methyl donors abrogates any detrimental effects of the LPD. Male C57BL6 mice were fed either a control normal protein diet (NPD; 18% protein; n = 8), an isocaloric LPD (LPD; 9% protein; n = 8) or an LPD supplemented with methyl donors (MD-LPD; choline chloride, betaine, methionine, folic acid, vitamin B12; n = 8) for a minimum of 7 weeks. Analysis of male serum fatty acid profiles by gas chromatography revealed elevated levels of saturated fatty acids and lower levels of mono- and polyunsaturated fatty acids in MD-LPD males when compared to NPD and/or LPD males. Testes of LPD males displayed larger seminiferous tubule cross section area when compared to NPD and MD-LPD males, while MD-LPD tubules displayed a larger luminal area. Furthermore, TUNNEL staining revealed LPD males possessed a reduced number of tubules positive for apoptosis, while gene expression analysis showed MD-LPD testes displayed decreased expression of the pro-apoptotic genes Bax, Csap1 and Fas when compared to NPD males. Finally, testes from MD-LPD males displayed a reduced telomere length but increased telomerase activity. These data reveal the significance of sub-optimal nutrition for paternal metabolic and reproductive physiology.

A decrease of docosahexaenoic acid in testes of mice fed a high-fat diet is associated with impaired sperm acrosome reaction and fertility

Obesity is a major worldwide health problem that is related to most chronic diseases, including male infertility. Owing to its wide impact on health, mechanisms underlying obesity-related infertility remain unknown. In this study, we report that mice fed a high-fat diet (HFD) for over 2 months showed reduced fertility rates and increased germ cell apoptosis, seminiferous tubule degeneration, and decreased intratesticular estradiol (E2) and E2-to-testosterone ratio. Interestingly, we also detected a decrease in testicular fatty acid levels, behenic acid (C22:0), and docosahexaenoic acid (DHA, 22:6n-3), which may be related to the production of dysfunctional spermatozoa. Overall, we did not detect any changes in the frequency of seminiferous tubule stages, sperm count, or rate of in vitro capacitation. However, there was an increase in spontaneous and progesterone-induced acrosomal exocytosis (acrosome reaction) in spermatozoa from HFD-fed mice. These data suggest that a decrease in E2 and fatty acid levels influences spermatogenesis and some steps of acrosome biogenesis that will have consequences for fertilization. Thus, our results add new evidence about the adverse effect of obesity in male reproduction and suggest that the acrosomal reaction can also be affected under this condition.

A pilot investigation of couple-level phthalates exposure and in vitro fertilization (IVF) outcomes

Phthalates are reproductive toxicants in experimental animal studies and exposure has been associated with infertility in human populations, although the results have been inconsistent. To help to address the data gap, we conducted a hypothesis-generating investigation of associations between urinary phthalate metabolites and reproductive outcomes among women (n = 56) and their male partners (n = 43) undergoing in vitro fertilization (IVF). Urine was collected from participants on the day of oocyte retrieval. Samples were analyzed for a series of phthalates, MEP, MBP, MPP, MHxP, MEHP, MEHHP, MECPP, MiNP, MiDP, MCHP, and MBzP, using liquid chromatography-tandem mass spectrometry. We employed Poisson regression with robust variance estimation to estimate associations between urinary phthalate levels and biochemical pregnancy and live birth, adjusted for partner's concentration and confounding factors. Doublings in women's MBP (relative risk (RR) = 0.32, 95 % CI: 0.13, 0.78), and men's MEHP (RR = 0.28, 95 % CI: 0.09, 0.83), were associated with a lower likelihood for pregnancy. Doublings in women's (RR = 0.08, 95 % CI: 0.01, 0.67) and men's (RR = 0.13, 95 % CI: 0.02, 0.92) MHxP were associated with a lower likelihood of live birth. Our results suggest that phthalate exposure may impact IVF outcomes, and underscore the importance of including male partners when investigating the impact of phthalate exposure on IVF. These results also suggest that clinical recommendations should include male partners for limiting phthalate exposure. Still, a larger and more comprehensive investigation is necessary to more definitively assess the risks.

Impact of paternal age on embryology and pregnancy outcomes in the setting of a euploid single-embryo transfer with ejaculated sperm: retrospective cohort study

Objective

To evaluate the impact of paternal age on embryology and pregnancy outcomes in the setting of a euploid single-embryo transfer.

Design

Retrospective cohort study.

Setting

Not applicable.

Patient(s)

Couples undergoing a first in vitro fertilization cycle with fresh ejaculated sperm who used intracytoplasmic sperm injection for fertilization followed by preimplantation genetic testing for aneuploidy and single-embryo transfer of a euploid embryo between January 2012 and December 2018.

Intervention(s)

Not applicable.

Main Outcome Measure(s)

Embryology outcomes assessed were fertilization rate, blastulation rate, and euploid rate. Pregnancy outcomes assessed included positive human chorionic gonadotropin rate, delivery rate, biochemical loss rate, and clinical loss rate.

Results

A total of 4,058 patients were assessed. After adjusting for female age, increased paternal age in the setting of fresh ejaculated sperm use was associated with decreased blastulation and decreased euploid rate using 40 years as an age cutoff.

Conclusion(s)

In this study, advancing paternal age appears to have a detrimental impact on rates of blastocyst formation and euploid status. However, if a euploid embryo is achieved, older paternal age does not appear to affect negatively pregnancy outcomes.

The impact of body mass index on reproductive hormones, testosterone/estradiol ratio and semen parameters

Introduction

The aim of this study was to evaluate the relationship between body mass index (BMI) and sperm parameters and reproductive hormone levels in patients with no known risk factors for infertility.

Material and methods

Four hundred patients who met the study's inclusion criteria were divided into three groups according to their BMI values as normal weight (BMI: 18.5-24.9 kg/m²), overweight (BMI 25-29.9 kg/m²), and obese (BMI ≥30 kg/m²). Semen parameters, reproductive hormone levels and testosterone/estradiol ratio were compared retrospectively between the groups.

Results

There was no significant difference between the groups in terms of age and infertility period. The mean BMI of all the patients was 26.6 ±4.08, and the BMI in the normal, overweight and obese groups were 22.6 ±1.7, 27.4 ±1.3, and 33.4 ±2.9, respectively (p <0.001). There was no significant difference between the groups in terms of serum follicle stimulating hormone, luteinizing hormone, estradiol, prolactin, semen volume, sperm concentration, total sperm count, and progressive and total motility. Serum testosterone (T) level and testosterone/estradiol (T/E2) ratio were significantly higher in the normal BMI group (p <0.001).

Conclusions

Adipose tissue increase was not significantly correlated with change in the semen parameters and it was negatively correlated with T levels and T/E2 ratio.

Potential Adverse Effects of Female and Male Obesity on Fertility: A Narrative Review

CONTEXT

Despite several studies documenting that obesity affects female and male fertility and leads to multiple adverse reproductive outcomes, the mechanisms involved are not elucidated. We aimed to summarize the potential adverse effects of female and male obesity, as well as the impact of weight loss on their fertility status.

EVIDENCE ACQUISITION

This review summarizes papers investigating the potential adverse effects of female and male obesity and the impact of weight-loss interventions on fertility among reproductive age populations. PubMed, Scopus, Web of Science, and Google Scholar databases were searched for retrieving studies published up to November 2019 on obesity/overweight among reproductive age populations.

RESULTS

The review of 68 studies revealed that female and male obesity/overweight increases the risk of sub-fecundity and infertility. The destructive effects of female obesity on reproduction are attributed to a variety of ovarian and extra-ovarian factors. In women with overweight or obesity, the time taken to conceive is longer, and they have a decreased fertility rate, increased requirement for gonadotropins, and higher miscarriage rate when compared to those with normal weight. Male obesity may lead to subfertility, mainly because of the disruption of the hypothalamus-pituitary-gonadal (HPG) axis, increased testicular temperature, impairment of the physical and molecular structure of sperm, decreased sperm quality, and erectile dysfunction due to peripheral vascular disease. Most studies recommend lifestyle interventions as first-line therapy in the general population of women and men with obesity and infertility.

CONCLUSIONS

This study shows the negative effects of female and male overweight and obesity on fertility. Therefore, educational interventions on the adverse effects of obesity and the benefits of weight reduction, such as increasing pregnancy rate, should be considered for couples seeking fertility.

Preconception diet, fertility, and later health in pregnancy

PURPOSE OF REVIEW

Women should enter pregnancy in the best possible health. There is increasing recognition of the importance of nutrition for reproductive health; however, key dietary factors in relation to optimizing fertility are nonexistent. The purpose of this review is to investigate dietary factors, preconception, and the association with fertility and later health in pregnancy.

RECENT FINDINGS

This article summarizes recent literature assessing preconception dietary intake and the association with fertility, time to pregnancy, and also the relationship with polycystic ovary syndrome and gestational diabetes; these conditions associate with each other, and also with infertility. The impact of paternal diet is also reported.

SUMMARY

There is recent interest investigating diet and time to pregnancy, suggesting higher intakes of fruit, minimal intake of fast food and sugar sweetened beverages, and a diet lower in glycemic load, may improve time to pregnancy. There is minimal recent literature on paternal diet and impact on fertility. Present advice to women with polycystic ovary syndrome is in line with international recommendations for lifestyle management to improve reproductive outcomes; and for gestational diabetes, prepregnancy may be an optimal time to improve dietary intakes, particularly through consumption of an overall healthy dietary pattern or a Mediterranean-style dietary pattern.

Evaluating the role of paternal factors in aetiology and prognosis of recurrent pregnancy loss: study protocol for a hospital-based multicentre case-control study and cohort study (REMI III project)

INTRODUCTION

Recurrent pregnancy loss (RPL) is defined as the spontaneous demise of two or more pregnancies before the fetus reaches viability. Despite investigation of multiple known maternal risk factors, in more than 50% of couples, this condition remains unexplained. Studies focusing on paternal factors in RPL are scarce, and therefore, paternal evaluation in RPL is currently very limited. However, regarding single miscarriage, there are multiple publications suggesting a contributive role of paternal factors. In this project, we aim to identify paternal factors associated with RPL and to improve couple-specific prediction of future pregnancy outcomes by developing a prediction model containing both maternal and paternal factors.

METHODS AND ANALYSIS

In a case-control design, the relation between unexplained RPL and paternal age, lifestyle factors, sperm DNA damage and immunomodulatory factors in peripheral blood and semen will be studied. Prospectively, 135 couples with naturally conceived unexplained RPL (cases) and 135 fertile couples without a history of pregnancy loss (controls) will be included, with collection of paternal blood and semen samples and documentation of clinical and lifestyle characteristics. In addition, 600 couples from both groups will be included retrospectively. To adjust for confounders, multivariate logistic regression will be used. The predictive value of paternal and maternal factors will be studied in the total RPL cohort consisting of approximately 735 couples. The primary outcome of the cohort study is live birth within 5 years after initial visit of the clinic. Secondary outcomes are ongoing pregnancy, time interval until next pregnancy and pregnancy complications.

ETHICS AND DISSEMINATION

This project is approved by the Medical Research Ethics Committee of the Leiden University Medical Center. No risks or burden are expected from the study. The findings of this study will be disseminated via peer-reviewed publications and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NL7762.

Obesity and Hypogonadism-A Narrative Review Highlighting the Need for High-Quality Data in Adolescents

The prevalence of obesity continues to rise in adult and pediatric populations throughout the world. Obesity has a direct impact on all organ systems, including the reproductive system. This review summarizes current knowledge about the effects of obesity on the male reproductive system across age, highlighting the need for more data in children and adolescents. Male hypogonadism is commonly seen in patients with obesity and affects the onset, duration, and progression of puberty. Different pathophysiologic mechanisms include increased peripheral conversion of testosterone to estrone and increased inflammation due to increased fat, both of which lead to suppression of the hypothalamic-pituitary-gonadotropin (HPG) axis and delayed development of secondary sexual characteristics in adolescent males. Evaluation of the HPG axis in obesity includes a thorough history to exclude other causes of hypogonadism and syndromic associations. Evaluation should also include investigating the complications of low testosterone, including increased visceral fat, decreased bone density, cardiovascular disease risk, and impaired mood and cognition, among others. The mainstay of treatment is weight reduction, but medications such as testosterone and clomiphene citrate used in adults, remain scarcely used in adolescents. Male hypogonadism associated with obesity is common and providers who care for adolescents and young adults with obesity should be aware of its impact and management.

Changes in total sperm count after gastric bypass and sleeve gastrectomy: the BARIASPERM prospective study

BACKGROUND

The massive weight loss induced by bariatric surgery is associated with major benefits, but the effect on semen variables is still uncertain.

OBJECTIVES

To explore semen modifications with gastric bypass and sleeve gastrectomy.

SETTING

Five French University Hospitals.

METHODS

Male candidates for bariatric surgery with no history of infertility were recruited in this controlled prospective study. Sperm characteristics were collected before surgery and then 6 months and up to 12 months after surgery.

RESULTS

Forty-six adult men who underwent gastric bypass (n = 20) or sleeve gastrectomy (n = 26) were included. Total sperm count tended to be lower at 6 months and showed a significant decrease at 12 months in both surgery groups, at -69.5 million (-96.8 to -42.2 million; P = 0.0021). Total sperm count at 12 months relative to baseline was -41.4 million (P = .0391) after gastric bypass and -91.1 million (P = .0080) after sleeve gastrectomy. This was counterbalanced by an associated resolution of hypogonadism and decrease of DNA fragmentation in most patients with time after surgery.

CONCLUSION

Improvement in some semen variables after bariatric surgery observed in 3 previous studies is in contrast to the lower mean total sperm count found in this study at 1 year. The possible reversibility of this effect in the long term and the impact of surgery on fertility both remain unknown.

Adverse effects of paternal obesity on the motile spermatozoa quality

Growing evidence suggests that paternal obesity may decrease male fertility potential. During infertility treatment with intra-cytoplasmic sperm injection (ICSI), a morphologically normal motile spermatozoon is injected into a mature egg, when possible. However, sperm motility and morphology per se do not reflect the sperm molecular composition. In this study, we aimed to assess the quality of motile spermatozoa in the context of obesity by analysing their conventional and molecular characteristics as well as their ability to promote early embryonic development. A prospective study was conducted on 128 infertile men divided into three groups: 40 lean, 42 overweight, and 46 obese men. Conventional sperm parameters (concentration, motility and morphology) and sperm molecular status (chromatin composition and integrity, 5-methycytosine (5-mC) and 5-hydroxycytosine (5-hmC) contents and oxidative stress level) were analysed on raw semen and/or on motile spermatozoa selected by density gradient or swim-up techniques. Morphokinetic analysis of the embryos derived from ICSI was performed using the Embryoviewer software. Our results showed that the motile sperm-enriched fraction from obese men exhibited higher levels of retained histones (p<0.001), elevated percentage of altered chromatin integrity (p<0.001), and decreased contents of 5-hmC (p<0.001), and 5-mC (p<0.05) levels as compared to that from lean men. Importantly, there were no statistically significant correlations between these molecular parameters and the percentages of morphologically normal motile spermatozoa. Regarding embryo morphokinetics, the CC1 (p<0.05) and CC3 (p<0.05) embryonic cell cycles were significantly delayed in the cleavage embryos of the obese group as compared to the embryos of the lean group. Our data is of particular interest because, besides demonstrating the negative impacts of obesity on motile spermatozoa molecular composition, it also highlights the possible risk of disturbing early embryonic cell cycles kinetics in the context of paternal obesity.

The Effects of Maternal and Paternal Body Mass Index on Live Birth Rate after Intracytoplasmic Sperm Injection Cycles

Background

We designed the present study to evaluate the simultaneous effect of obesity in couples on in vitro fertilization/ intracytoplasmic sperm injection (IVF/ICSI) outcomes.

Materials and Methods

In this cross-sectional study, performed at Royan Institute between January 2013 and January 2014, we evaluated the recorded data of all patients during this time period. The study population was limited to couples who underwent ICSI or IVF/ICSI cycles with autologous oocytes and fresh embryo transfers. We recorded the heights and weights of both genders and divided them into groups according to body mass index (BMI). Multilevel logistic regression analysis was used to determine the odds ratio for live births following ICSI or IVF/ICSI.

Results

In total, 990 couples underwent IVF/ICSI cycles during the study period. Among the ovulatory women, a significant difference existed between the BMI groups. There was a 60% decrease [95% confidence interval (CI): 0.11-0.83] in the odds of a live birth among overweight subjects and 84% (95% CI: 0.02-0.99) decrease among obese subjects. Among the anovulatory women, the association between the BMI and live births presented no clear tendencies. We did not observe any significant relationship between male BMI and live birth rate. The results demonstrated no significant association between the couples' BMI and live birth rate.

Conclusion

Based on the present findings, increased female BMI independently and negatively influenced birth rates after ICSI. However, increased male BMI had no impact on live births after ICSI, either alone or combined with increased female BMI.

An ICSI rate of 90% minimizes complete failed fertilization and provides satisfactory implantation rates without elevating fetal abnormalities

IVF cycles utilizing the ICSI technique for fertilization have been rising over the 25 years since its introduction, with indications now extending beyond male factor infertility. We have performed ICSI for 87% of cases compared with the ANZARD average of 67%. This retrospective study reports on the outcomes of 1547 autologous ART treatments undertaken over a recent 3-year period. Based on various indications, cases were managed within 3 groupings - IVF Only, ICSI Only or IVF-ICSI Split insemination where oocytes were randomly allocated. Overall 567 pregnancies arose from mostly single embryo transfer procedures up to December 2016, with 402 live births, comprising 415 infants and a low fetal abnormality rate (1.9%) was recorded. When the data was adjusted for confounders such as maternal age, measures of ovarian reserve and sperm quality, it appeared that IVF-generated and ICSI-generated embryos had a similar chance of both pregnancy and live birth. In the IVF-ICSI Split model, significantly more ICSI-generated embryos were utilised (2.5 vs 1.8; p < 0.003) with productivity rates of 67.8% for pregnancy and 43.4% for livebirths per OPU for this group. We conclude that ART clinics should apply the insemination method which will maximize embryo numbers and the first treatment for unexplained infertility should be undertaken within the IVF-ICSI Split model. Whilst ICSI-generated pregnancies are reported to have a higher rate of fetal abnormalities, our data is consistent with the view that the finding is not due to the ICSI technique per se.

Systematic review and meta-analysis of the impact of preconception lifestyle interventions on fertility, obstetric, fetal, anthropometric and metabolic outcomes in men and women

STUDY QUESTION

What is the impact of preconception lifestyle interventions on live birth, birth weight and pregnancy rate?

SUMMARY ANSWER

Lifestyle interventions showed benefits for weight loss and increased natural pregnancy rate, but not for live birth or birth weight.

WHAT IS KNOWN ALREADY

Evidence on the practice and content of preconception counseling and interventions is variable and limited.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis (MA). Main search terms were those related to preconception lifestyle. Database searched were Ovid MEDLINE(R), EBM Reviews, PsycINFO, EMBASE and CINAHL Plus. No language restriction was placed on the published articles. The final search was performed on 10 January 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were non-pregnant women of childbearing age intent on conceiving or their male partners. Exclusion criteria include participants with BMI < 18 kg/m2, animal trials, hereditary disorder in one or both partners and trials focusing solely on alcohol or smoking cessation/reduction, micronutrient supplementation, or diabetes control. Anthropometric, fertility, obstetric and fetal outcomes were assessed. Bias and quality assessments were performed.

MAIN RESULTS AND THE ROLE OF CHANCE

The search returned 1802 articles and eight studies were included for analysis. Populations targeted were primarily overweight or obese subfertile women seeking reproductive assistance, with few community-based studies and none including men. MA showed greater reduction in weight (n = 3, P < 0.00001, mean difference: -3.48 kg, 95% CI: -4.29, -2.67, I2 = 0%) and BMI (n = 2, P < 0.00001, mean difference: -1.40 kg/m2, 95% CI: -1.95, -0.84, I2 = 24%) with intervention. The only significant fertility outcome was an increased natural pregnancy rate (n = 2, P = 0.003, odds ratio: 1.87, CI: 1.24, 2.81, I2 = 0%). No differences were observed for ART adverse events, clinical pregnancy, pregnancy complications, delivery complications, live birth, premature birth, birth weight, neonatal mortality or anxiety. Risk of bias were high for three studies, moderate for three studies and low for two studies, Attrition bias was moderate or high in majority of studies.

LIMITATIONS, REASONS FOR CAUTION

Results were limited to subfertile or infertile women who were overweight or obese undergoing ART with no studies in men. The heterogeneous nature of the interventions in terms of duration and regimen means no conclusions could be made regarding the method or components of optimal lifestyle intervention. Attrition bias itself is an important factor that could affect efficacy of interventions.

WIDER IMPLICATIONS OF THE FINDINGS

Existing preconception lifestyle interventions primarily targeted overweight and obese subfertile women undergoing ART with a focus on weight loss. It is important to note that natural conception increased with lifestyle intervention. This emphasizes the need for further research exploring optimal components of preconception lifestyle interventions in the broader population and on the optimal nature, intensity and timing of interventions.

STUDY FUNDING/COMPETING INTEREST(S)

No conflict of interest declared. C.L.H. is a National Heart Foundation Postdoctoral Research Fellow. B.H. is funded by an Alfred Deakin Postdoctoral Research Fellowship. H.J.T. and B.W.M. hold NHMRC Practitioner fellowships. L.J.M. is supported by a SACVRDP Fellowship; a program collaboratively funded by the NHF, the South Australian Department of Health and the South Australian Health and Medical Research Institute.

PROSPERO REGISTRATION NUMBER

CRD42015023952.

Paternal obesity: how bad is it for sperm quality and progeny health?

There is substantial evidence that paternal obesity is associated not only with an increased incidence of infertility, but also with an increased risk of metabolic disturbance in adult offspring. Apparently, several mechanisms may contribute to the sperm quality alterations associated with paternal obesity, such as physiological/hormonal alterations, oxidative stress, and epigenetic alterations. Along these lines, modifications of hormonal profiles namely reduced androgen levels and elevated estrogen levels, were found associated with lower sperm concentration and seminal volume. Additionally, oxidative stress in testis may induce an increase of the percentage of sperm with DNA fragmentation. The latter, relate to other peculiarities such as alteration of the embryonic development, increased risk of miscarriage, and development of chronic morbidity in the offspring, including childhood cancers. Undoubtedly, epigenetic alterations (ie, DNA methylation, chromatin modifications, and small RNA deregulation) of sperm related to paternal obesity and their consequences on the progeny are poorly understood determinants of paternal obesity-induced transmission. In this review, we summarize and discuss the data available in the literature regarding the biological, physiological, and molecular consequences of paternal obesity on male fertility potential and ultimately progeny health.

Couples' body composition and time-to-pregnancy

STUDY QUESTION

Is couples' body compositions associated with reduced fecundity as measured by a longer time-to-pregnancy (TTP)?

SUMMARY ANSWER

Couples whose BMI are within obese class II (≥35 kg/m2) have a longer TTP in comparison to leaner (BMI < 25 kg/m2) couples, observed only when both partner's BMI was jointly modeled.

WHAT IS KNOWN ALREADY

Extremes of BMI have been associated with a longer TTP and with less successful assisted reproductive technology (ART) outcomes. To our knowledge, the association between measured adiposity in both partners of the couple and prospectively measured TTP has not been investigated despite pregnancy being a couple-dependent outcome.

STUDY DESIGN, SIZE, DURATION

Prospective cohort with preconception recruitment of 501 couples trying for pregnancy and recruited from 16 counties in Michigan and Texas between 2005 and 2009. Couples were followed daily for up to a year of trying or until a hCG pregnancy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In-home standardized anthropometric assessment of couples upon enrollment included measured height and weight using calibrated stadiometers and scales, and measured waist and hip circumferences. Discrete-time Cox regression was used to estimate fecundability odds ratios (FORs) and 95% CIs, controlling for potential confounders including age, number of days of vigorous physical activity, serum cotinine concentration, race, education, free cholesterol levels for each partner in partner-specific models and for both partners in couple-based models as well as average acts of intercourse per menstrual cycle and menstrual cycle regularity.

MAIN RESULTS AND THE ROLE OF CHANCE

Neither male nor female partner's BMI was associated with TTP when modeled individually. However, obese class II (BMIs ≥ 35.0 kg/m2) couples experienced a reduction in fecundability in both unadjusted (FOR = 0.45; 95% CI: 0.23, 0.89) and adjusted analyses (aFOR = 0.41; 95% CI: 0.17, 0.98) resulting in a longer TTP in comparison to couples with normal BMI (<25 kg/m2). Female partners' waist circumference ≥88.6 cm was associated with a significant reduction in fecundability in the unadjusted model (FOR = 0.64; 95% CI: 0.48, 0.86) but not in the adjusted model (aFOR = 0.77; 95% CI: 0.55, 1.08) in comparison to females with a smaller (<80 cm) circumference.

LIMITATIONS, REASONS FOR CAUTION

BMI and waist circumference are proxy measures of body composition and residual confounding cannot be eliminated. Findings may not be generalizable to clinical populations.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first cohort study known to us with preconception enrollment of couples who underwent standardized anthropometric assessment and for whom TTP was prospectively measured. The findings underscore the importance of considering both partners' body composition for fecundity outcomes and preconception guidance.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Contracts #N01-HD-3-3355, N01-HD-3-3356 and N01-HD-3-3358). The authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Obesity aggravates toxic effect of BPA on spermatogenesis

Both bisphenol A (BPA) and obesity affect male reproductive system. However, whether there is an interaction between them remains poorly understood. The aim of the present study was to evaluate the interaction between BPA exposure and obesity on semen quality and elucidate the mechanism in humans and animals. We firstly analyzed the interaction on semen volume, sperm count per ejaculate, sperm concentration and sperm motility in 357 men, and found that urinary BPA concentration was significantly correlated with sperm count per ejaculate in obese men (β=-34.62; 95% CI: -60.75, -8.48; P=0.01). Then we validated the interaction using lean and obese mice with administration of BPA. Significant interactions between BPA exposure and obesity on sperm count and sperm concentration was observed in mice. Finally, we conducted metabolomics analyses to identify metabolites related to the interaction. Metabolites related to the interaction, including capric acid, dodecanoic acid, l-palmitoylcarnitine, niacinamide, etc., are known to play critical roles in fatty acid oxidation and tricarboxylic acid cycle indicating increased oxidative stress associated with male reproductive dysfunction. Thus, our study finds an interaction between BPA exposure and obesity on sperm count and reveals potential metabolic mechanisms. It emphasizes the importance to study interactions between endocrine disrupting chemicals and obesity, and opens avenues for the possible use of animal models in identifying the interactions.

Obesity, energy balance and spermatogenesis

Obesity has grown to pandemic proportions. It affects an increasing number of children, adolescents and young adults exposed to the silent comorbidities of this disorder for a longer period. Infertility has arisen as one important comorbidity associated with the energy dysfunction promoted by obesity. Spermatogenesis is a highly regulated process that is determined by specific energetic requirements. The reproductive potential of males relies on hormonal-dependent and -independent stimuli that control sperm quality. There are conflicting data concerning the impact of male overweight and obesity on sperm quality, as well as on the possible paternal-induced epigenetic trait inheritance of obesity. In addition, it remains a matter of debate whether massive weight loss induced by lifestyle interventions, drugs or bariatric surgery may or may not benefit obese men seeking fatherhood. Herein, we propose to discuss how energy balance may modulate hormonal signalling and sperm quality in overweight and obese men. We also discuss some molecular mechanisms that mediate obesity-related dysfunction in male reproductive system and how paternal obesity may lead to trait inheritance. Finally, we will discuss how lifestyle modifications and sustained weight loss, particularly the loss achieved by bariatric surgery, may revert some of the deleterious effects of obesity in men and their offspring.

Male caffeine and alcohol intake in relation to semen parameters and in vitro fertilization outcomes among fertility patients

Much of the literature on the impact of male caffeine and alcohol intake on reproductive outcomes has utilized semen quality as a proxy for male fertility, although semen parameters have a limited predictive value for spontaneous pregnancy. The objective of this study was to investigate whether male caffeine and alcohol intakes are associated with semen parameters and assisted reproductive technology outcome. The Environment and Reproductive Health Study, an ongoing prospective cohort study, enrolls subfertile couples presenting for treatment at an academic fertility center (2007-2012). A total of 171 men with 338 semen analyses and 205 assisted reproductive technology cycles were included in this analysis. Diet was assessed using a 131-item food frequency questionnaire. Mixed models adjusting for potential confounders were used to evaluate the relationships of male caffeine and alcohol intakes with semen parameters and assisted reproductive technology outcomes. There was no association between male caffeine and alcohol intake and semen quality. Male caffeine intake was negatively related to live birth after assisted reproductive technologies (p-trend < 0.01), and male alcohol intake was positively related to live birth after assisted reproductive technologies (p-trend = 0.04). Adjusted live birth rate among couples with a male partner in the highest quartile of caffeine intake (≥272 mg/day) compared to couples with a male partner in the lowest quartile of intake (<99 mg/day) was 19% vs. 55%, respectively, p < 0.01. In terms of alcohol intake, adjusted live birth rate among couples with a male partner in the highest quartile of alcohol intake (≥22 g/day) compared to couples with a male partner in the lowest quartile of intake (<3 g/day) was 61% vs. 28%, respectively, p = 0.05. In conclusion, male pre-treatment caffeine and alcohol intakes were associated with live birth after assisted reproductive technologies, but not with semen parameters, among fertility patients.

Does being overweight affect seminal variables in fertile men?

The effect of being overweight on seminal variables was assesed in 165 fertile men. Participants were divided into three groups: fertile men with normal body mass index (BMI) (18.5-24.9 kg/m²), fertile overweight men (BMI 25-29.9 kg/m²) and fertile obese men (BMI >30 kg/m²). Medical history was taken, a clinical examination conducted. Semen analysis was undertaken and BMI measured. Seminal reactive oxygen species (ROS) was estimated by chemiluminescent assay, sperm vitality by the hypo-osmotic swelling test and sperm DNA fragmentation by propidium iodide staining with flowcytometry. Fertile obese men had significantly lower sperm concentration, progressive sperm motility and sperm normal morphology, with significantly higher seminal ROS and sperm DNA fragmentation compared with fertile normal-weight men and overweight men (all P < 0.05). BMI was negatively correlated with sperm concentration (r = -0.091; P = 0.014), progressive sperm motility (r = -0.697; P = 0.001), normal sperm morphology (r = -0.510; P = 0.001), sperm vitality (r = -0.586; P = 0.001), but positively correlated with sperm DNA fragmentation percentage (r = 0.799; P = 0.001) and seminal ROS (r = 0.673; P = 0.001). Increased BMI was found to affect semen parameters negatively even in fertile men.

Epigenetics in male reproduction: effect of paternal diet on sperm quality and offspring health

Epigenetic inheritance and its underlying molecular mechanisms are among the most intriguing areas of current biological and medical research. To date, studies have shown that both female and male germline development follow distinct paths of epigenetic events and both oocyte and sperm possess their own unique epigenomes. Fertilizing male and female germ cells deliver not only their haploid genomes but also their epigenomes, which contain the code for preimplantation and postimplantation reprogramming and embryonal development. For example, in spermatozoa, DNA methylation profile, DNA-associated proteins, protamine 1:protamine 2 ratio, nucleosome distribution pattern, histone modifications and other properties make up a unique epigenetic landscape. However, epigenetic factors and mechanisms possess certain plasticity and are affected by environmental conditions. Paternal and maternal lifestyle, including physical activity, nutrition and exposure to hazardous substances, can alter the epigenome and, moreover, can affect the health of their children. In male reproductive health, data are emerging on epigenetically mediated effects of a man's diet on sperm quality, for example through phytochemicals, minerals and vitamins, and nutritional support for subfertile men is already being used. In addition, studies in animal models and human epidemiological data point toward a transgenerational effect of the paternally contributed sperm epigenome on offspring health.

Effect of paternal overweight or obesity on IVF treatment outcomes and the possible mechanisms involved

Leukocyte telomere lengths (LTLs) are shorter in obese compared with normal weight people. However, it is not known whether sperm telomere length (STL) is related to obesity. The aim of the study was to evaluate the impact of men’s body mass index (BMI) on STL, embryo quality, and clinical outcomes in couples undergoing IVF. In total, 651 couples were recruited, including 345 men with a normal BMI and 306 men with an overweight BMI (normal BMI group: 20–25 kg/m²; overweight BMI group: >28 kg/m²). We found that couples with male’s BMI over 28 kg/m² exhibited a significantly lower fertilization rate, good-quality embryo rate and clinical pregnancy rate compared to their normal BMI counterparts. The mean STL in the overweight BMI group was also significantly shorter than that of the normal BMI group. The results also showed that individuals with higher BMI had higher ROS (Reactive oxygen species) content and sperm DNA fragmentation rate when compared with normal BMI individuals. Mitochondrial activity was also lower in the overweight BMI group than in the normal BMI group. This is the first report to find that STL is shorter in overweight/obese men, which may account for their poorer treatment outcomes in IVF cycles.

Male obesity and subfertility, is it really about increased adiposity?

The prevalence of overweight and obesity in reproductive-aged men is increasing worldwide, with >70% of men >18 years classified as overweight or obese in some western nations. Male obesity is associated with male subfertility, impairing sex hormones, reducing sperm counts, increasing oxidative sperm DNA damage and changing the epigenetic status of sperm. These changes to sperm function as a result of obesity, are further associated with impaired embryo development, reduced live birth rates and increased miscarriage rates in humans. Animal models have suggested that these adverse reproductive effects can be transmitted to the offspring; suggesting that men's health at conception may affect the health of their children. In addition to higher adiposity, male obesity is associated with comorbidities, including metabolic syndrome, hypercholesterolemia, hyperleptinemia and a pro-inflammatory state, all which have independently been linked with male subfertility. Taken together, these findings suggest that the effects of male obesity on fertility are likely multifactorial, with associated comorbidities also influencing sperm, pregnancy and subsequent child health.

Impact of men's dairy intake on assisted reproductive technology outcomes among couples attending a fertility clinic

Intake of full-fat dairy has been linked to lower semen quality but whether this leads to decreased fertility is unknown. To address this question, we prospectively evaluated the association of men's dairy intake with treatment outcomes of subfertile couples undergoing assisted reproductive technology (ART). We followed 142 men from couples undergoing infertility treatment with ART at an academic fertility centre between 2007 and 2014. Couples completed dietary assessments prior to treatment, and the female partners underwent a total of 248 ART cycles. Multivariable generalized linear mixed models were used to examine the association of dairy intake with fertilization, implantation, clinical pregnancy and live birth rates adjusting for age, body mass index, smoking status, total exercise time, dietary patterns, alcohol, caffeine, total energy intake, and female dairy intake. Intake of dairy foods, regardless of their fat content, was not associated with fertilization, implantation, clinical pregnancy or live birth rates. The adjusted live birth rates (95% confidence interval) for couples in increasing quartiles of men's dairy intake were 0.42 (0.25, 0.60), 0.25 (0.13, 0.42), 0.26 (0.15, 0.41), and 0.44 (0.27, 0.63) (p linear trend = 0.73). Results remained similar after adjustment for female partner intake of dairy foods. Overall, men's dairy intake was not associated with treatment outcomes of couples undergoing ART.

Obesity and reproduction: a committee opinion

The purpose of this ASRM Practice Committee report is to provide clinicians with principles and strategies for the evaluation and treatment of couples with infertility associated with obesity. This revised document replaces the Practice Committee document titled, "Obesity and reproduction: an educational bulletin," last published in 2008 (Fertil Steril 2008;90:S21-9).

Paternal obesity negatively affects male fertility and assisted reproduction outcomes: a systematic review and meta-analysis

This systematic review investigated the effect of paternal obesity on reproductive potential. Databases searched were Pubmed, Ovid, Web of Science, Scopus, Cinahl and Embase. Papers were critically appraised by two reviewers, and data were extracted using a standardized tool. Outcomes were: likelihood of infertility, embryo development, clinical pregnancy, live birth, pregnancy viability, infant development, sperm; concentration, morphology, motility, volume, DNA fragmentation, chromatin condensation, mitochondrial membrane potential (MMP), and seminal plasma factors. Thirty papers were included, with a total participant number of 115,158. Obese men were more likely to experience infertility (OR = 1.66, 95% CI 1.53-1.79), their rate of live birth per cycle of assisted reproduction technology (ART) was reduced (OR = 0.65, 95% CI 0.44-0.97) and they had a 10% absolute risk increase of pregnancy non-viability. Additionally, obese men had an increased percentage of sperm with low MMP, DNA fragmentation, and abnormal morphology. Clinically significant differences were not found for conventional semen parameters. From these findings it can be concluded that male obesity is associated with reduced reproductive potential. Furthermore, it may be informative to incorporate DNA fragmentation analysis and MMP assessment into semen testing, especially for obese men whose results suggest they should have normal fertility.

The impact of lifestyle modifications, diet, and vitamin supplementation on natural fertility

BACKGROUND

Infertility is a relatively common condition. When patients are confronted with this diagnosis, there are medical, psychological, and financial sequelae. Patients often wonder if there is anything they can do to optimize their natural fertility or increase the effectiveness of infertility treatments.

FINDINGS

If there is a clear impact on fertility, such as with smoking and alcohol, cessation should be advised. Similarly, weight loss should be recommended if the BMI is in the overweight and obese category, and weight gain should be recommended for an underweight BMI. The evidence surrounding other lifestyle modifications is less clear. There are conflicting data regarding an optimal fertility diet and consumption of vitamins and supplements. Antioxidants seem to improve semen parameters in men, but the effect on female fertility is less clear. If conflicting evidence exists, such as with caffeine consumption or exercise, moderation should be emphasized. Finally, the diagnosis of infertility and subsequent fertility treatments are stressful for both partners. The psychological aspects should not be ignored and methods such as yoga and cognitive behavioral therapy may be beneficial.

CONCLUSION

Continued research will determine the optimal lifestyle modifications to achieve pregnancy.

Men's meat intake and treatment outcomes among couples undergoing assisted reproduction

OBJECTIVE

To study the relationship between men's meat intake and clinical outcomes in couples undergoing infertility treatment with the use of assisted reproductive technology (ART).

DESIGN

Prospective cohort study.

SETTING

Fertility center.

PATIENT(S)

A total of 141 men whose female partners underwent 246 ART cycles from 2007 to 2014.

INTERVENTION(S)

None. Total and specific types of meat intake were estimated from dietary questionnaires.

MAIN OUTCOME MEASURE(S)

Fertilization, implantation, clinical pregnancy, and live-birth rates per initiated cycle. Mixed-effects models account for multiple IVF cycles per woman.

RESULT(S)

There was a positive association between poultry intake and fertilization rate, with a 13% higher fertilization rate among men in the highest quartile of poultry intake compared with those in the lowest quartile (78% vs. 65%). Processed meat intake was inversely related to fertilization rate in conventional IVF cycles but not in IVF cycles using intracytoplasmic sperm injection. The adjusted fertilization rates for men in increasing quartiles of processed meat intake were 82%, 67%, 70%, and 54% in conventional IVF cycles. Men's total meat intake, including intake of specific types of meat, was not associated with implantation, clinical pregnancy, or live-birth rates.

CONCLUSION(S)

Poultry intake was positively associated with fertilization rates, whereas processed meat intake was negatively associated with fertilization rates among couples undergoing conventional IVF. This, however, did not translate into associations with clinical pregnancy or live-birth rates.