Dietary Fat Intake and Fecundability in 2 Preconception Cohort Studies

Healthy eating index and risk of diminished ovarian reserve: a case-control study

Diminished ovarian reserve (DOR) is associated with reduced fertility and poor reproductive outcomes. The association between dietary patterns and DOR was not well studied. The purpose of this study was to evaluate the relationship between adhering to the healthy eating index (HEI-2015) and the risk of DOR. In this case-control study, 370 Iranian women (120 with DOR and 250 age- and BMI-matched controls) were examined. A reliable semi-quantitative food frequency questionnaire was used to collect diet-related data. We analyzed the HEI-2015 and their dietary intake data to determine major dietary patterns. The multivariable logistic regression was used in order to analyze the association between HEI-2015 and risk of DOR. We found no significant association between HEI-2015 score and risk of DOR in the unadjusted model (OR 0.78; 95%CI 0.59, 1.03). After controlling for physical activity and energy intake, we observed that women in the highest quartile of the HEI-2015 score had 31% decreased odds of DOR (OR 0.69; 95%CI 0.46, 0.93). This association remained significant even after adjusting for all potential confounders. Overall, increased adherence to HEI may lead to a significant reduction in the odds ratio of DOR. Clinical trials and prospective studies are needed to confirm this association.

Association between Life's Essential 8 and Infertility as Well as the Mediating Effects of Oxidative Stress and Inflammatory Factors Among U.S. Women Aged 18-45 Years

Management of cardiovascular disease in pregnancy is important, yet the association between cardiovascular health and infertility is rarely reported. In this study, we aimed to explore the association between Life's Essential 8 (LE8), a novel cardiovascular health (CVH) measure, and infertility, and to investigate potential mediating mechanisms. This study investigated cross-sectional data from the 2013-2018 National Health and Nutrition Examination Survey. LE8 score (ranging from 0 to 100) was calculated as the unweighted average of eight CVH metrics. The association between LE8 and infertility was explored through weighted multiple logistic regression. Restricted cubic splines were used to explore nonlinear correlation. In addition, mediation analysis was conducted to investigate the role of oxidative stress and inflammatory markers systematically. After strict exclusion criteria, 1703 American women aged 18-45 years were included. After full adjustment, the LE8 score showed a negative correlation with infertility [per 1 SD increase, OR = 0.675, 95% CI: 0.553-0.824], with a linear dose-response relationship (non-linear P = 0.122). Similar linear negative correlations were found between health factor scores and infertility, with higher body mass index and glucose scores having a significantly lower risk of infertility. Stratified analyses showed a stronger inversed relationship between LE8 and infertility in younger populations. Moreover, mediation analysis revealed that uric acid concentration and lymphocyte count mediated the effect of LE8 on infertility (P < 0.05). LE8 and its subscale scores were linearly and negatively associated with infertility, which may be mediated in part through uric acid and lymphocyte count. Focusing on weight management and glycemic control can effectively reduce the risk of infertility.

Do Popular Diets Impact Fertility?

Infertility affects 15% of the population in developed countries, and its prevalence is increasing. Fertility can be influenced by different factors. Although key factors like maternal age cannot be changed, there is growing evidence that other modifiable factors, such as diet, can have an impact on fertility. Diet has become increasingly important in recent years for a number of reasons: the new trend toward a healthy lifestyle, the higher prevalence of certain digestive disorders, a lack of time that leads people to consume more prepared and processed food, and personal choice to not eat meat, among others. To meet these needs, several diets have recently become popular, such as the Mediterranean diet, known as the gold standard of health; the DASH diet, known for preventing hypertension; the Western diet, characterized by processed food; the ketogenic diet, characterized by low carbohydrate intake; and the vegetarian diet, which is the choice for people who do not eat meat or animal by-products. Diets present a unique composition characterized by the presence or absence of specific nutrients, which have also been associated with male and female fertility individually. This review assesses the impact of these diets and of macro- and micronutrients on both female and male fertility.

Effect of omega-3 supplements or diets on fertility in women: A meta-analysis

Objective

This study aimed to assess the effect of increased omega-3 consumption on fertilization rates and the probability of women getting pregnant. This study is needed because different perspectives exist regarding the use of omega-3 fatty acids in enhancing fertility among women with reproductive issues, and information for those planning a spontaneous pregnancy is limited.

Methods

PubMed, Clinical Trials, CINAHL/EBSCO, Medline Complete, Cochrane Library, and Google Scholar were searched for articles published until April 2021, and the search was limited to articles in English language. The search strategy included the following key words: "in-vitro fertilization (IVF)," "intracytoplasmic sperm injection techniques (ICSI)," "pregnancy," "omega-3 fatty acid," "alpha-linolenic acid," "eicosapentaenoic acid," "docosahexaenoic acid," "n-3 polyunsaturated fatty acid," and "fish oil and seafood." Studies reporting female fertility occurring naturally or IVF/ICSI concurrent with omega-3 intake were included. Retrospective studies, studies including postmenopausal women, and unevenly matched control and study groups were excluded. To assess bias, we used the Cochrane Handbook for Systematic Reviews of Interventions, version 5.1.0. To synthesize the findings from the studies included in this review, a meta-analysis was conducted using calculated or extracted odds ratios (OR) of clinical pregnancies and fertilization rates for each group in each study.

Results

We included six trials involving 1789 women who received fertility treatment, four trials involving 2607 women who conceived naturally, and three trials involving 1725 oocytes for fertility rates. Aggregated ORs for the effects of omega-3 on pregnancies were 1.74, 1.36, and 2.14 for women who received fertility treatment, those who conceived naturally, and fertilization rate, respectively. All these results were significant (p ≤ 0.01), although they had high heterogeneity I2>68 %.

Conclusion

This systematic review and meta-analysis suggest that omega-3 intake significantly improves women's pregnancy and fertilization rates; however, the high heterogeneity in this review somewhat limits its interpretation. Therefore, further prospective randomized studies are necessary to better understand this relationship.

Dietary Patterns and Fertility

Diet has a key role in the reproductive axis both in males and females. This review aims to analyze the impacts of different dietary patterns on fertility. It appears that the Mediterranean diet has a predominantly protective role against infertility, while the Western diet seems to be a risk factor for infertility. Moreover, we focus attention also on dietary patterns in different countries of the World (Middle Eastern diet, Asian diet). In particular, when analyzing single nutrients, a diet rich in saturated fatty acids, cholesterol, animal proteins, and carbohydrates with high glycemic index is highly associated with male and female infertility. Finally, we evaluate the effects of vegetarian, vegan, and ketogenic diets on fertility, which seem to be still unclear. We believe that comprehension of the molecular mechanisms involved in infertility will lead to more effective and targeted treatments for infertile couples.

Association between nutrient intake and female infertility: a study based on NHANES database

BACKGROUND

This study was designed to investigate the association between nutrients and female infertility.

METHODS

A cross-sectional study on 18-45 years of age reproductive-age women was conducted using the data from the National Health and Nutrition Examination Surveys (NHANES) for the periods 2013-2014 and 2015-2016. Multivariate logistic regression analysis was performed to evaluate the association between nutrients and female infertility. Subgroup analysis was applied to the body mass index (BMI). Results were summarised using an odds ratio (OR) with a 95% confidence interval (CI).

RESULTS

Of the total 1713 women, 204 women (11.91%) were infertile. The result demonstrated that higher intake of carbohydrate (OR: 0.46, 95% CI: 0.24-0.86, p = 0.018), vitamin A (OR: 0.44, 95% CI: 0.24-0.80, p = 0.009), vitamin C (OR: 0.48, 95% CI: 0.26-0.88, p = 0.020), magnesium (OR: 0.36, 95% CI: 0.17-0.76, p = 0.009), iron (OR: 0.43, 95% CI: 0.23-0.82, p = 0.012), lycopene (OR: 0.55, 95% CI: 0.33-0.91, p = 0.022), and total folate (OR: 0.38, 95% CI: 0.20-0.70, p = 0.003) were associated with a lower risk of female infertility. The subgroup analysis also reported that intakes of vitamin A, vitamin C, and lycopene were related to a lower risk of female infertility among women with a BMI being 18.5-24.9 kg/m2. Among women with BMI > 24.9 kg/m2, high intakes of magnesium, iron and total folate were associated with a decreased risk of female infertility.

CONCLUSIONS

The intake of several nutrients is associated with a decreased risk of female infertility. These findings provide insight into potentially modifiable lifestyle factors associated with female infertility.

Assessing the influence of preconception diet on female fertility: a systematic scoping review of observational studies

BACKGROUND

Preconception diet is a proposed modifiable risk factor for infertility. However, there is no official guidance for women in the preconception period as to which dietary approaches may improve fertility.

OBJECTIVE AND RATIONALE

A comprehensive synthesis of the relevant evidence is key to determine the potentially effective dietary patterns and components as well as evidence gaps, and to provide information for nutritional recommendations for couples planning a pregnancy.

SEARCH METHODS

In this systematic scoping review, four electronic databases (Medline and EMBASE via Ovid processing, CAB Direct, and CINAHL via EBSCO) were searched for observational studies (prospective and retrospective cohort, cross-sectional, and case-control studies) from inception to 27 September 2021. Eligible studies included women of reproductive age during the preconception period, and evaluated exposures related to preconception diet and outcomes related to fertility. Results were synthesized using a descriptive approach.

OUTCOMES

A total of 36 studies were eligible for inclusion (31 prospective, 3 cross-sectional, and 2 case-control studies) and were published between 2007 and 2022. Of the assessed dietary exposures, increased adherence to the Mediterranean diet displayed the strongest and most consistent association with improved clinical pregnancy rates. Reducing trans fatty acids (TFAs), saturated fatty acids, and discretionary food intake (fast food and sugar-sweetened beverages) were associated with improvements in live birth, clinical pregnancy rates, and related ART outcomes. The dietary components of seafood, dairy, and soy demonstrated inconsistent findings across the few included studies.

WIDER IMPLICATIONS

Due to heterogeneity and the limited available literature on most exposures, there is insufficient evidence to support any specific dietary approach for improving fertility. However, following some of the dietary approaches outlined in this review (anti-inflammatory diets, reducing TFA, and discretionary food intake) are consistent with broad healthy eating guidelines, have little to no associated risk, and offer a plausible set of possible benefits. This warrants further exploration in randomized controlled trials.

Beyond body mass index: a synthesis of lifestyle factors that may influence in vitro fertilisation outcomes

There are several lifestyle factors that are thought to potentially impact in vitro fertilisation outcomes, including body mass index, smoking, alcohol consumption, caffeine, dietary patterns and physical activity. Eligibility criteria for in vitro fertilisation in England often require individuals to be non-smokers, drug free and have a body mass index <30kg/m2. Some researchers have questioned the scientific and ethical basis for the use of body mass index thresholds in fertility treatment, citing evidence that other factors may have a greater effect on the chance of success of in vitro fertilisation. This article aims to briefly synthesise the current evidence on how other factors such as smoking, alcohol, recreational drugs, smoking, caffeine, dietary patterns and physical activity may impact in vitro fertilisation outcomes.

Association of male fatty acid intake with fecundability among couples planning pregnancy

STUDY QUESTION

To what extent is male fatty acid intake associated with fecundability among couples planning pregnancy?

SUMMARY ANSWER

We observed weak positive associations of male dietary intakes of total and saturated fatty acids with fecundability; no other fatty acid subtypes were appreciably associated with fecundability.

WHAT IS KNOWN ALREADY

Male fatty acid intake has been associated with semen quality in previous studies. However, little is known about the extent to which male fatty acid intake is associated with fecundability among couples attempting spontaneous conception.

STUDY DESIGN, SIZE, DURATION

We conducted an internet-based preconception prospective cohort study of 697 couples who enrolled during 2015-2022. During 12 cycles of observation, 53 couples (7.6%) were lost to follow-up.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were residents of the USA or Canada, aged 21-45 years, and not using fertility treatment at enrollment. At baseline, male participants completed a food frequency questionnaire from which we estimated intakes of total fat and fatty acid subtypes. We ascertained time to pregnancy using questionnaires completed every 8 weeks by female participants until conception or up to 12 months. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs for the associations of fat intakes with fecundability, adjusting for male and female partner characteristics. We used the multivariate nutrient density method to account for energy intake, allowing for interpretation of results as fat intake replacing carbohydrate intake. We conducted several sensitivity analyses to assess the potential for confounding, selection bias, and reverse causation.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 697 couples, we observed 465 pregnancies during 2970 menstrual cycles of follow-up. The cumulative incidence of pregnancy during 12 cycles of follow-up after accounting for censoring was 76%. Intakes of total and saturated fatty acids were weakly, positively associated with fecundability. Fully adjusted FRs for quartiles of total fat intake were 1.32 (95% CI 1.01-1.71), 1.16 (95% CI 0.88-1.51), and 1.43 (95% CI 1.09-1.88) for the second, third, and fourth vs the first quartile, respectively. Fully adjusted FRs for saturated fatty acid intake were 1.21 (95% CI 0.94-1.55), 1.16 (95% CI 0.89-1.51), and 1.23 (95% CI 0.94-1.62) for the second, third, and fourth vs the first quartile, respectively. Intakes of monounsaturated, polyunsaturated, trans-, omega-3, and omega-6 fatty acids were not strongly associated with fecundability. Results were similar after adjustment for the female partner's intakes of trans- and omega-3 fats.

LIMITATIONS, REASONS FOR CAUTION

Dietary intakes estimated from the food frequency questionnaire may be subject to non-differential misclassification, which is expected to bias results toward the null in the extreme categories when exposures are modeled as quartiles. There may be residual confounding by unmeasured dietary, lifestyle, or environmental factors. Sample size was limited, especially in subgroup analyses.

WIDER IMPLICATIONS OF THE FINDINGS

Our results do not support a strong causal effect of male fatty acid intakes on fecundability among couples attempting to conceive spontaneously. The weak positive associations we observed between male dietary fat intakes and fecundability may reflect a combination of causal associations, measurement error, chance, and residual confounding.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the National Institutes of Health, grant numbers R01HD086742 and R01HD105863. In the last 3 years, PRESTO has received in-kind donations from Swiss Precision Diagnostics (home pregnancy tests) and Kindara.com (fertility app). L.A.W. is a consultant for AbbVie, Inc. M.L.E. is an advisor to Sandstone, Ro, Underdog, Dadi, Hannah, Doveras, and VSeat. The other authors have no competing interests to report.

TRIAL REGISTRATION NUMBER

N/A.

The Influence of Metabolic Factors and Diet on Fertility

Infertility is a disease globally affecting 20-30% of the reproductive age female population. However, in up to 50% on recorded cases, problems with infertility are ascribed to men; therefore, it is important to popularize healthy eating also in this group. During the last decade, it has been observed that society's lifestyle changed drastically: reduced energy expenditure in physical activity per day, increased consumption of hypercaloric and high-glycemic-index foods with high content of trans fats, and reduced consumption of dietary fiber, which negatively affects fertility. Increasing evidence points to a link between diet and fertility. It is becoming clear that well-planned nutrition can also contribute to the effectiveness of ART. The low-GI plant-based diet appears to have a positive effect, especially when it is based on Mediterranean dietary patterns: rich in antioxidants, vegetable protein, fiber, MUFA fatty acids, omega-3, vitamins, and minerals. Importantly, this diet has been shown to protect against chronic diseases associated with oxidative stress, which also translates into pregnancy success. As lifestyle and nutrition seem to be important factors affecting fertility, it is worth expanding knowledge in this regard among couples trying to conceive a child.

The Role of Dietary Nutrients in Male Infertility: A Review

Male infertility is the main health issue with economic, psychological, and medical attributions. Moreover, it is characterized by an inability to produce a sufficient amount of sperm for the fertilization of an oocyte. Dietary nutrients (DN) have a great effect on male reproductive potential. Observations have indicated that adding DN may protect or treat male infertility. The scope of this criticism is to scrutinize the DN, such as omega-3 fatty acids, vitamins, minerals and other phytochemicals, in enhancing the semen attributes, sperm bioenergetics and sperm functionality in male infertility. It seems that diets rich in omega-3 fatty acids affect sperm quality and maintain the sperm membrane and mitochondria stability. An administration of phytochemicals caused an escalation in sperm mitochondrial function and a decrease in oxidative damage. Furthermore, sundry dietary natural phytochemicals differentially affect (negatively or positively) sperm motility, semen quality, and mitochondrial function, dependent on their levels. Vitamins and trace elements are also nutritional modulators in reducing oxidative stress, thereby enhancing sperm quality, which is accurately connected with sperm mitochondrial function. Also, we described the different types of DN as mitochondrial enhancer for sperm functionality and health. We believe that understanding the DN supports sperm mitochondria and epigenetic modulators that may be responsible for sperm quality and health, and will lead to more embattled and efficient therapeutics for male infertility.

Development of a nutrition screening tool to identify need for dietetic intervention in female infertility

BACKGROUND

One in seven couples are impacted by infertility in the UK, and female infertility is often associated with several health conditions impacted by nutrition. Despite many studies aimed at identifying the critical role of nutrition in infertility, there is currently no screening tool that identifies nutritional risk factors for infertility.

AIM

To propose a self-administered screening tool to identify women who would benefit from nutritional intervention to promote fertility.

METHODS

A narrative review was carried out to identify and summarise modifiable nutritional risk factors that can influence female fertility, including comorbidities that can influence nutrition intake, absorption, and metabolism.

KEY FINDINGS

A nutrition screening tool outlining modifiable nutrition risk factors potentially improving female fertility has been proposed, comprising of BMI, medical history and quality of diet and lifestyle which would aid in designing evidence based dietetic services for female infertility.

Dietary Supplement Intake and Fecundability in a Singapore Preconception Cohort Study

Subfertility is a global problem affecting millions worldwide, with declining total fertility rates. Preconception dietary supplementation may improve fecundability, but the magnitude of impact remains unclear. This prospective cohort study aimed to examine the association of preconception micronutrient supplements with fecundability, measured by time to pregnancy (TTP). The study was conducted at KK Women's and Children's Hospital, Singapore, between February 2015 and October 2017, on 908 women aged 18-45 years old, who were trying to conceive and were enrolled in the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO). Baseline sociodemographic characteristics and supplement intake were collected through face-to-face interviews. The fecundability ratio (FR) was estimated using discrete-time proportional hazard modelling. Adjusting for potentially confounding variables, folic acid (FA) (FR 1.26, 95% confidence interval 1.03-1.56) and iodine (1.28, 1.00-1.65) supplement users had higher fecundability compared to non-users. Conversely, evening primrose oil supplement users had lower fecundability (0.56, 0.31-0.99) than non-users. In this study, preconception FA and iodine supplementation were associated with shortened TTP, while evening primrose oil use was associated with longer TTP. Nonetheless, the association between supplement use and the magnitude of fecundability changes will need to be further confirmed with well-designed randomised controlled trials.

The Treatment of Complementary and Alternative Medicine on Female Infertility Caused by Endometrial Factors

Recently, with the development of the social economy, the incidence of infertility has increased year by year. With its complex etiology and diversified syndromes, infertility has become one of the most important diseases that plague the physical and mental health of women of childbearing age worldwide. Endometrial factors as an important part affecting female reproductive capacity, due to which induced repeated abortion and multiple uterine cavity operations occur, can destruct endometrium, failing to provide a normal implantation environment for zygote, thus resulting in infertility. Many patients failed to achieve expected results after receiving conventional treatments such as hormone therapy, assisted reproductive technology (ART), granulocyte colony-stimulating factor (G-CSF) therapy, and cell therapy, then turn to complementary and alternative medicine (CAM) therapies for help. Aiming at clarifying the effectiveness and mechanisms of CAM therapy in the treatment of infertility caused by endometrial factors, our paper systematically searched and studied present related literature on the PubMed, CNKI, and other databases, focusing on the aspects of clinical application and mechanism explorations and highlighting the therapeutic effects of Chinese herbal medicine (CHM), acupuncture, and moxibustion on such diseases. Moreover, this paper also introduces the CAM treatments of traditional Chinese medicine (TCM) retention enema, neuromuscular electrical stimulation (NMES), photobiomodulation therapy, dietary intervention, and other measures for infertility caused by endometrial factors, in order to provide a reference for subsequent basic research and clinical work.

Association between polyunsaturated fatty acid intake and infertility among American women aged 20-44 years

Background

Infertility is a nationwide public health priority in the U.S. However, few studies have investigated the effects of dietary intake of polyunsaturated fatty acids (PUFAs) on female infertility. This study explored the association between PUFA intake and risk of infertility.

Methods

A total of 1,785 women aged 20-44 years from three National Health and Nutrition Examination Survey cycles (2013-2018) were included in this cross-sectional study. The intake of PUFAs was obtained from a 24-h dietary interview on two separate days with a 3-10-day interval, and nutrient residue models were used. Fertility status was assessed by positive response to two relative questions via a questionnaire. Logistic regression models were used and some covariates were adjusted.

Results

Among all the participants, 340 (19.05%) women suffered from infertility. The intake of docosahexaenoic acid (DHA) (OR = 0.998, 95% CI 0.998, 0.009) was slightly related to the risk of infertility. In contrast, women with higher α-linolenic acid (ALA) (OR = 1.416, 95% CI 1.138, 1.763) and linoleic acid (LA) intake (OR = 1.020, 95% CI 1.002, 1.038) presented with a relatively higher risk of primary infertility. Furthermore, in 20-34-year-old women, higher omega-6/omega-3 was significant associated with the risk of infertility (OR = 1.002, 95%CI 1.000, 1.005).

Conclusions

Our results suggest that PUFA intake is only slightly associated with infertility. The higher the DHA intake, the lower the risk of infertility regardless of age. In women with primary infertility, ALA and LA has negative effect.

A Systematic Review of the Effects of High-Fat Diet Exposure on Oocyte and Follicular Quality: A Molecular Point of View

Worldwide, infertility affects between 10 and 15% of reproductive-aged couples. Female infertility represents an increasing health issue, principally in developing countries, as the current inclinations of delaying pregnancy beyond 35 years of age significantly decrease fertility rates. Female infertility, commonly imputable to ovulation disorders, can be influenced by several factors, including congenital malformations, hormonal dysfunction, and individual lifestyle choices, such as smoking cigarettes, stress, drug use and physical activity. Moreover, diet-related elements play an important role in the regulation of ovulation. Modern types of diet that encourage a high fat intake exert a particularly negative effect on ovulation, affecting the safety of gametes and the implantation of a healthy embryo. Identifying and understanding the cellular and molecular mechanisms responsible for diet-associated infertility might help clarify the confounding multifaceted elements of infertility and uncover novel, potentially curative treatments. In this view, this systematic revision of literature will summarize the current body of knowledge of the potential effect of high-fat diet (HFD) exposure on oocyte and follicular quality and consequent female reproductive function, with particular reference to molecular mechanisms and pathways. Inflammation, oxidative stress, gene expression and epigenetics represent the main mechanisms associated with mammal folliculogenesis and oogenesis.

Female infertility and diet, is there a role for a personalized nutritional approach in assisted reproductive technologies? A Narrative Review

Female infertility is a major public health concern and a global challenge. It is a disorder of the reproductive system, defined as the inability to achieve a clinical pregnancy. Nutrition and other environmental factors are found to impact reproductive health in women as well as the outcome of assisted reproductive technologies (ART). Dietary factors, such as polyunsaturated fatty acids (PUFA), fiber as well as the intake of Mediterranean diet appear to exert beneficial effects on female reproductive outcomes. The exact mechanisms associating diet to female fertility are yet to be identified, although genomic, epigenomic, and microbial pathways may be implicated. This review aims to summarize the current knowledge on the impact of dietary components on female reproduction and ART outcomes, and to discuss the relevant interplay of diet with genome, epigenome and microbial composition.

Infertility in Men: Advances towards a Comprehensive and Integrative Strategy for Precision Theranostics

Male infertility is an increasing and serious medical concern, though the mechanism remains poorly understood. Impaired male reproductive function affects approximately half of infertile couples worldwide. Multiple factors related to the environment, genetics, age, and comorbidities have been associated with impaired sperm function. Present-day clinicians rely primarily on standard semen analysis to diagnose male reproductive potential and develop treatment strategies. To address sperm quality assessment bias and enhance analysis accuracy, the World Health Organization (WHO) has recommended standardized sperm testing; however, conventional diagnostic and therapeutic options for male infertility, including physical examination and semen standard analysis, remain ineffective in relieving the associated social burden. Instead, assisted reproductive techniques are becoming the primary therapeutic approach. In the post-genomic era, multiomics technologies that deeply interrogate the genome, transcriptome, proteome, and/or the epigenome, even at single-cell level, besides the breakthroughs in robotic surgery, stem cell therapy, and big data, offer promises towards solving semen quality deterioration and male factor infertility. This review highlights the complex etiology of male infertility, especially the roles of lifestyle and environmental factors, and discusses advanced technologies/methodologies used in characterizing its pathophysiology. A comprehensive combination of these innovative approaches in a global and multi-centric setting and fulfilling the suitable ethical consent could ensure optimal reproductive and developmental outcomes. These combinatorial approaches should allow for the development of diagnostic markers, molecular stratification classes, and personalized treatment strategies. Since lifestyle choices and environmental factors influence male fertility, their integration in any comprehensive approach is required for safe, proactive, cost-effective, and noninvasive precision male infertility theranostics that are affordable, accessible, and facilitate couples realizing their procreation dream.

Omega-3 fatty acid supplementation and fecundability

STUDY QUESTION

Is self-reported use of omega-3 fatty acid supplements associated with fecundability, the probability of natural conception, in a given menstrual cycle?

SUMMARY ANSWER

Prospectively recorded omega-3 supplement use was associated with an increased probability of conceiving.

WHAT IS KNOWN ALREADY

In infertile women, omega-3 fatty acid intake has been associated with increased probability of pregnancy following IVF. In natural fertility, studies are conflicting, and no study of natural fertility has evaluated omega-3 fatty acid supplementation and fecundity.

STUDY DESIGN, SIZE, DURATION

Secondary data analysis of 900 women contributing 2510 cycles in Time to Conceive (TTC), a prospective, time to pregnancy cohort study from 2008 to December 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 30-44 years, trying to conceive <3 months, without history of infertility were followed using standardized pregnancy testing. While attempting to conceive, women daily recorded menstrual cycle events and supplement and medication intake using the Cerner Multum Drug Database. Supplements and vitamins containing omega-3 were identified. Omega-3 use, defined as use in at least 20% of days in a given menstrual cycle, in each pregnancy attempt cycle was determined. A discrete-time Cox proportional hazards model was used to calculate the fecundability ratio.

MAIN RESULTS AND THE ROLE OF CHANCE

Women taking omega-3 supplementation were more likely to be younger, thinner, nulligravid, white and to take vitamin D, prenatal and multivitamins compared to women not taking omega-3s. After adjusting for age, obesity, race, previous pregnancy, vitamin D and prenatal and multivitamin use, women taking omega-3 supplements had 1.51 (95% CI 1.12, 2.04) times the probability of conceiving compared to women not taking omega-3s.

LIMITATIONS, REASONS FOR CAUTION

Our study was not a randomized controlled trial. The women who used omega-3 supplements may represent a more health-conscious population. We sought to address this by adjusting for multiple factors in our model. Additionally, the omega-3 fatty acid supplements that TTC participants used included multiple types and brands with varying dosages of omega-3 fatty acids. Women reported the type of supplement they were taking but not the concentration of omega-3s in that supplement. It is therefore not possible to compare dosing or a dose-response relationship in our study.

WIDER IMPLICATIONS OF THE FINDINGS

Omega-3 supplementation may present a feasible and inexpensive modifiable factor to improve fertility. Randomized controlled trials are needed to further investigate the benefits of omega-3 supplementation for women trying to conceive naturally.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Division of Reproductive Endocrinology and Infertility at the University of North Carolina at Chapel Hill, the NIH/NICHD (R21 HD060229-01 and R01 HD067683-01), and in part by the Intramural Research Program of the National Institute of Environmental Health Sciences (Z01ES103333). The authors declare that there is no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

The Influence of Diet on Ovulation Disorders in Women—A Narrative Review

Female infertility is commonly due to ovulation disorders. They are mostly related to polycystic ovary syndrome, which is currently viewed as one of the most common endocrine disorders in women of reproductive age. Ovulation-related female fertility is influenced by multiple factors which may include: age, smoking cigarettes, stress, use of psychoactive substances, and physical activity. Moreover, diet-related factors play an important role in the regulation of ovulation. Dietary components that exert a positive influence on ovulation include: carbohydrate products with low glycemic index, plant protein, monounsaturated and polyunsaturated fatty acids, folic acid, vitamin D, antioxidants, and iron. A diet based on the structure of the Mediterranean diet also seems beneficial. Components that have a negative influence mostly include high glycemic index carbohydrates, large amounts of animal protein, saturated fatty acids, and trans fatty acids, which are typically found in the Western model of nutrition. Due to the paucity of studies that presented a direct link between nutrition and the risk of anovulatory infertility, this study aimed to summarize the most recent research on the influence of dietary factors on ovulation disorders and indicate the possibilities of future research.

Women's and men's intake of omega-3 fatty acids and their food sources and assisted reproductive technology outcomes

BACKGROUND

Long-chain omega-3 fatty acids and their food sources have garnered interest as a potential nutrient with wide-range health benefits, including fertility.

OBJECTIVE

This study aimed to investigate the association of women's and men's intake of omega-3 fatty acids and omega-3 rich-foods with semen quality and outcomes of infertility treatment with assisted reproductive technologies.

STUDY DESIGN

Couples presenting to the Massachusetts General Hospital were invited to enroll in a prospective cohort study (2007-2020). Male and female diets were assessed using a validated 131-item food frequency questionnaire. The primary outcomes were implantation, clinical pregnancy, and live birth probabilities. The secondary outcomes included total and clinical pregnancy loss and conventional semen parameters, for males only. We estimated the relationship between intakes of omega-3 fatty acids, nuts, and fish and the probability (95% confidence interval) of study outcomes using generalized linear mixed models to account for repeated treatment cycles per participant while simultaneously adjusting for age, body mass index, smoking status, education, dietary patterns, total energy intake, and male partner diet.

RESULTS

A total of 229 couples and 410 assisted reproductive technology cycles were analyzed for primary and secondary outcomes. Of note, 343 men contributing 896 semen samples were included in analyses for semen quality measures. Women's docosahexaenoic acid + eicosapentaenoic acid intake was positively associated with live birth. The multivariable-adjusted probabilities of live birth for women in the bottom and top quartiles of eicosapentaenoic acid + docosahexaenoic acid intake were 0.36 (95% confidence interval, 0.26-0.48) and 0.54 (95% confidence interval, 0.42-0.66) (P trend=.02). Eicosapentaenoic acid + docosahexaenoic acid intake was inversely related to the risk of pregnancy loss, which was 0.53 among women in the lowest quartile of eicosapentaenoic acid + docosahexaenoic acid intake and 0.05 among women in the highest quartile (P trend=.01). Men's intake of total omega-3 fatty acids was positively related to sperm count, concentration, and motility, but unrelated to any assisted reproductive technology outcomes. Similar associations were observed when evaluating the intake of primary food sources of these fatty acids.

CONCLUSION

Women's consumption of omega-3 fatty acids and omega-3-rich foods may improve the probability of conception by decreasing the risk of pregnancy loss. In addition, men's intake of omega-3 fatty acids may influence semen quality.

Diet and pravastatin administration prior to in vitro fertilization treatment may improve pregnancy outcome in women with dyslipidemia

In this study, we aimed to identify whether using statins may increase the chance of pregnancy in In Vitro Fertilisation / Intra-Cytoplasmic Sperm Injection (IVF/ICSI) patients with hyperlipidaemia. Therefore, in this retrospective cohort study, 70 patients constituted the study population and all patients were managed by lipid lowering diet. Ten mg pravastatin (pravachol DEVA, Istanbul, Turkey) was added to therapy in case of resistant hypercholesterolaemia after 15 days of the diet. Fifty-one patients were treated with diet only and the remaining nineteen patients were offered both diet and pravastatin. Clinical pregnancy rate was significantly better with the patients who used pravastatin (68.4% vs. 39.2%, p = .029). Ongoing pregnancy rates were 63.2% and 33.3% with pravastatin and diet only, respectively, which were statistically significant (p:.024). According to multivariate analysis, pravastatin use was found independently and statistically significant for clinical pregnancy and ongoing pregnancy rate after IVF/ICSI in patients with dyslipidemia (HR 3.79; 95% CI 1.31-10.97; p:.014 and HR 3.18; 95% CI 1.22-8.27; p:.018). When we analysed stratified data according to the AMH levels, we noticed that as AMH levels increased, the pregnancy rates increased; the most benefit from pravastatin was in the group with AMH levels >2 ng/mL.IMPACT STATEMENTWhat is already known on this subject? Dyslipidemia in In IVF/ICSI patients with polycystic ovary syndrome had negative impact on pregnancy ratesWhat the results of this study add? The findings of the study support that pravastatin may help to improve pregnancy outcome, especially in normal and high responders, regardless of whether decreased serum LDL or total cholesterol level.What the implications are of these findings for clinical practice and/or further research? As a result of our data, we speculated that it should be routine to investigate the lipid profile in every IVF/ICSI patient and should be treated accordingly, if necessary.

Dietary patterns are associated with improved ovarian reserve in overweight and obese women: a cross-sectional study of the Lifestyle and Ovarian Reserve (LORe) cohort

BACKGROUND

Growing evidence suggests that adherence to certain dietary patterns is associated with improved fecundity and reproductive outcomes in the general population and infertile couples assisted reproductive treatments. The objective of this study was to assess if dietary patterns are associated with ovarian reserve in reproductive age women without a history of infertility.

METHODS

This was a cross-sectional study of 185 women in the Lifestyle and Ovarian Reserve (LORe) cohort. Women aged 18-44 without a history of infertility were recruited from the local community at an academic medical center. Subjects completed validated food frequency and physical activity questionnaires to assess patterns over the year prior to presentation. Dietary patterns including a Western (including meat, refined carbohydrates, high-calorie drinks), prudent (including fruits, vegetables, olive oil and nuts), fertility (lower intake of trans fat with higher intake of monounsaturated fatty acids, increased intake of plant based protein, high-fat dairy, lower glycemic load carbohydrates and supplemental iron) and profertility diet (PFD) (characterize by whole grains, soy and seafood, low pesticide residue produce, supplemental folic acid, B12 and vitamin D) were identified through principal component analysis. Main outcome measures were serum antimullerian hormone concentration (AMH) (ng/mL) and antral follicle count (AFC) obtained by transvaginal ultrasound.

RESULTS

After stratifying by BMI, adjusting for age, smoking and physical activity, dietary patterns were not associated with ovarian reserve in normal weight women. Increased adherence to a profertility diet in overweight and obese women (BMI ≥ 25 kg/m²) was associated with a significantly higher AMH. Women in the third and fourth quartiles of PFD adherence had a mean AMH concentration of 1.45 ng/mL (95%CI 0.33-2.56, p = 0.01) and 1.67 ng/mL (95%CI 0.60-2.74, p = 0.003) higher than women in the lowest quartile respectively. The highest adherence to PFD was also associated with a higher AFC in women with a BMI ≥ 25 kg/m² (β = 7.8, 95%CI 0.003-15.34, p < 0.05). Other common dietary patterns were not significantly associated with ovarian reserve.

CONCLUSIONS

Increased adherence to a profertility diet is associated with improved markers of ovarian reserve in overweight and obese women. These findings provide novel insight on potential modifiable lifestyle factors associated with ovarian reserve.

Perikonzeptioneller Einfluss von Ernährung und Mikronährstoffen auf die Reproduktionsfunktion

Die Bedeutung von Mikronährstoffen und einer insgesamt „gesunden Ernährung“ in der Schwangerschaft ist unstrittig. Im Gegensatz dazu ist die Datenlage zum Einfluss der perikonzeptionellen Ernährung auf die Konzeption, Implantation und den weiteren Schwangerschaftsverlauf weit weniger klar. Gesichert scheint, dass ein hoher Anteil von Vollkornprodukten, Früchten, Gemüse, Fisch und Olivenöl bei moderatem Anteil von Kohlenhydraten günstige Effekte entfaltet. Bei Kinderwunsch ist heute die Folsäuresubstitution obligat, diese kann nach aktuellen Leitlinien der Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften durch Vitamin D ergänzt werden.

Prepregnancy adherence to plant-based diet indices and exploratory dietary patterns in relation to fecundability

BACKGROUND

Modest associations have been reported between specific food groups or nutrients and fecundability [measured by time to pregnancy (TTP)]. Examining overall diets provides a more holistic approach towards understanding their associations with fecundability. It is not known whether plant-based diets indices or exploratory dietary patterns are associated with fecundability.

OBJECTIVES

We examine the associations between adherence to 1) plant-based diet indices; and 2) exploratory dietary patterns and fecundability among women planning pregnancy.

METHODS

Data were analyzed from the Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO) study. Prepregnancy diet was assessed using a semi-quantitative FFQ from which the overall, healthful, and unhealthful plant-based diet indices (oPDI, hPDI, and uPDI, respectively) were calculated. Exploratory dietary patterns were derived using factor analysis based on 44 predefined food groups. Participants were categorized into quintiles based on their dietary pattern scores. TTP (expressed in menstrual cycles) was ascertained within a year from the prepregnancy dietary assessment. Discrete-time proportional hazard models, adjusted for confounders, were used to estimate fecundability ratios (FRs) and 95% CIs, with FR > 1 indicating a shorter TTP.

RESULTS

Among 805 women, 383 pregnancies were confirmed by ultrasound scans. Compared with women in the lowest quintile, those in the highest quintile of the uPDI had reduced fecundability (FR of Q5 compared with Q1, 0.65; 95% CI, 0.46-0.91; P trend, 0.009). Conversely, greater adherence to the hPDI was associated with increased fecundability (1.46; 95% CI, 1.02-2.07; P trend, 0.036). The oPDI was not associated with fecundability. Among the 3 exploratory dietary patterns, only greater adherence to the Fast Food and Sweetened Beverages (FFSB) pattern was associated with reduced fecundability (0.61; 95% CI, 0.40-0.91; P trend, 0.018).

CONCLUSIONS

Greater adherence to the uPDI or the FFSB dietary pattern was associated with reduced fecundability among Asian women. Greater adherence to the hPDI may be beneficial for fecundability, though this requires confirmation by future studies.

Female dietary patterns and outcomes of in vitro fertilization (IVF): a systematic literature review

Background

Infertility affects up to 15% of couples. In vitro fertilization (IVF) treatment has modest success rates and some factors associated with infertility and poor treatment outcomes are not modifiable. Several studies have assessed the association between female dietary patterns, a modifiable factor, and IVF outcomes with conflicting results. We performed a systematic literature review to identify female dietary patterns associated with IVF outcomes, evaluate the body of evidence for potential sources of heterogeneity and methodological challenges, and offer suggestions to minimize heterogeneity and bias in future studies.

Methods

We performed systematic literature searches in EMBASE, PubMed, CINAHL, and Cochrane Central Register of Controlled Trials for studies with a publication date up to March 2020. We excluded studies limited to women who were overweight or diagnosed with PCOS. We included studies that evaluated the outcome of pregnancy or live birth. We conducted an initial bias assessment using the SIGN 50 Methodology Checklist 3.

Results

We reviewed 3280 titles and/or titles and abstracts. Seven prospective cohort studies investigating nine dietary patterns fit the inclusion criteria. Higher adherence to the Mediterranean diet, a ‘profertility’ diet, or a Dutch ‘preconception’ diet was associated with pregnancy or live birth after IVF treatment in at least one study. However, causation cannot be assumed. Studies were potentially hindered by methodological challenges (misclassification of the exposure, left truncation, and lack of comprehensive control for confounding) with an associated risk of bias. Studies of the Mediterranean diet were highly heterogenous in findings, study population, and methods. Remaining dietary patterns have only been examined in single and relatively small studies.

Conclusions

Future studies with rigorous and more uniform methodologies are needed to assess the association between female dietary patterns and IVF outcomes. At the clinical level, findings from this review do not support recommending any single dietary pattern for the purpose of improving pregnancy or live birth rates in women undergoing IVF treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00757-7.

Essentiality of Trace Elements in Pregnancy, Fertility, and Gynecologic Cancers-A State-of-the-Art Review

Gynecological neoplasms pose a serious threat to women's health. It is estimated that in 2020, there were nearly 1.3 million new cases worldwide, from which almost 50% ended in death. The most commonly diagnosed are cervical and endometrial cancers; when it comes to infertility, it affects ~48.5 million couples worldwide and the number is continually rising. Ageing of the population, environmental factors such as dietary habits, environmental pollutants and increasing prevalence of risk factors may affect the reproductive potential in women. Therefore, in order to identify potential risk factors for these issues, attention has been drawn to trace elements. Trace mineral imbalances can be caused by a variety of causes, starting with hereditary diseases, finishing with an incorrect diet or exposure to polluted air or water. In this review, we aimed to summarize the current knowledge regarding trace elements imbalances in the case of gynecologic cancers as well as female fertility and during pregnancy.

Fatty acids intake and outcomes of assisted reproduction in women referring to an Italian Fertility Service: cross sectional analysis of a prospective cohort study

BackgroundInfertility involves 15% of couples in Italy and approximately 10-12% worldwide.Focusing on female fertility, it can underline multiple causes, among them the diet has a great influence. Methods We investigated whether the consumption of some fatty acids affects four outcomes of the assisted reproduction techniques. From September 2014 to December 2016, women referring to our Italian fertility unit, eligible for assisted reproduction techniques, were invited to participate. Information on dietwere recorded through a validated food frequency questionnaire. Results494 women were included, of whom95% achieved good quality oocytes, 87% resulted in embryo transfer, 32.0%in clinical pregnancies, and 24.5% in pregnancy at term.The fourth quartile of saturated fatty acids consumption, compared to the first one, showed an association with clinical pregnancy (adjusted relative risk 0.67, 95% confidence interval 0.45 to 1.00, p=0.0491). Some associations emerge accounting for confounders. Age was associated with clinical pregnancy and pregnancy at term in the models considering all fatty intakes and food groups variables but was not associated with oocytes quality and embryo transfer. Physical activity was associated with clinical pregnancy. ConclusionsThere is biologic plausibility of the effect of omega-3 and omega-6 polyunsaturated fatty acids on oocyte development via eicosanoids synthesis, even if our results showed limited associations.Future research is aimed to measure serum levels of fatty acids and investigate the assisted reproduction techniques' outcomes. This article is protected by copyright. All rights reserved.

Unsaturated Fatty Acid Intake During Periconception and Incidence of Achieving Pregnancy: A Systematic Review and Meta-Analysis

Background: Previous studies suggest that maternal diets enriched in unsaturated fatty acids may have a positive effect on pregnancy success. The aim of the present study was to conduct a systematic review and meta-analysis to evaluate whether increased dietary intake of polyunsaturated fatty acids (PUFAs) or monounsaturated fatty acids (MUFAs) during the periconception period has beneficial effects on the achievement of pregnancy in women.

Methods: The electronic databases PubMed, Medline and Cochrane Central Register, as well as references in related review articles, were searched to find studies assessing the effects of unsaturated fatty acid dietary intake during the periconception period on the achievement of pregnancy in women. Pregnancy was confirmed by high levels of hCG (biochemical means) and ultrasound confirmation of a gestational sac and heartbeat (clinical means).

Results: For the meta-analysis evaluating the effects of periconceptional diets enriched in PUFAs on pregnancy, four articles, providing data on 2,121 patients, were included. Results showed that periconceptional intake of PUFAs has no significant effects on achieving pregnancy compared to controls, according to both the fixed effects and random effects models (RR = 0.99, 95% CI 0.98–1.00). Further secondary analysis considering ω-6 and ω-3 PUFAs separately showed no significant effects on achieving pregnancy compared to controls. On the other hand, for the meta-analysis evaluating the effects of periconceptional diets enriched in MUFAs on achieving pregnancy, five articles, providing data on 2,473 patients, were included. Results showed that periconceptional dietary intake of MUFAs has significant effects on achieving pregnancy compared to controls according to the fixed effects model (RR = 1.03, 95% CI 1.01–1.06, p < 0.02) but not to the random effects model, due to heterogeneity. A secondary meta-analysis excluding one study which led to heterogeneity showed significant effects of MUFAs on achieving pregnancy compared to controls, according to both the fixed effects and random effects models (RR = 1.03, 95% CI 1.01–1.05, p < 0.02).

Conclusion: The meta-analysis of published clinical studies suggests that diets enriched in MUFAs, although not those enriched in PUFAs, may have a positive effect on pregnancy success as determined by HCG and ultrasonography.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42021239355, identifier: CRD42021239355.

Female Fertility and the Nutritional Approach: The Most Essential Aspects

Infertility is an increasing problem that affects couples attempting pregnancy. A growing body of evidence points to a link between diet and female fertility. In fact, data show that a diet high in trans fats, refined carbohydrates, and added sugars can negatively affect fertility. Conversely, a diet based on the Mediterranean dietary patterns, i.e., rich in dietary fiber, omega-3 (ɷ-3) fatty acids, plant-based protein, and vitamins and minerals, has a positive impact on female fertility. An unhealthy diet can disrupt microbiota composition, and it is worth investigating whether the composition of the gut microbiota correlates with the frequency of infertility. There is a lack of evidence to exclude gluten from the diet of every woman trying to become pregnant in the absence of celiac disease. Furthermore, there are no data concerning adverse effects of alcohol on female fertility, and caffeine consumption in the recommended amounts also does not seem to affect fertility. On the other hand, phytoestrogens presumably have a positive influence on female fertility. Nevertheless, there are many unanswered questions with regard to supplementation in order to enhance fertility. It has been established that women of childbearing age should supplement folic acid. Moreover, most people experience vitamin D and iodine deficiency; thus, it is vital to control their blood concentrations and consider supplementation if necessary. Therefore, since diet and lifestyle seem to be significant factors influencing fertility, it is valid to expand knowledge in this area.

Optimizing natural fertility: a committee opinion

This committee opinion provides practitioners with suggestions for optimizing the likelihood of achieving pregnancy in couples or individuals attempting conception who have no evidence of infertility. This document replaces the document of the same name previously published in 2013 (Fertil Steril 2013;100:631-7).

Hair mercury levels, intake of omega-3 fatty acids and ovarian reserve among women attending a fertility center

OBJECTIVE

To investigate the association of hair mercury (Hg) levels with antral follicle count (AFC), as a marker of ovarian reserve, and evaluate whether this relationship differed among women with high vs. low total intake of long chain omega-3 polyunsaturated fatty acids (n3PUFA) from foods and supplements.

DESIGN

We included 353 women attending an academic fertility center (2007-2019) who had data on hair Hg levels, total n3PUFA intake, and AFC.

METHODS

Hair Hg levels were assessed using a Direct Mercury Analyser, total n3PUFA intake was estimated using an extensively validated food frequency questionnaire, and AFC was assessed by transvaginal ultrasonography. Poisson regression models adjusted for potential confounders were used to evaluate the association of hair Hg levels (divided into tertiles, and as above vs below EPA reference (1 ppm)) with AFC. Associations were also evaluated after stratification by median n3PUFA intake (≤0.124% vs. >0.125% calories/week).

RESULTS

Women's median hair Hg level was 0.60 ppm (range = 0.001-8.60 ppm), with more than 30% > 1 ppm (EPA reference level). Hair Hg was positively related to AFC after adjusting for age, BMI, smoking status, infertility diagnosis, and alcohol intake. However, associations became attenuated after adjustment for intake of total n3PUFA. The positive associations of hair Hg and AFC were observed only among women above the median total n3PUFA intake. Specifically, women who consumed >0.125% calories/week of total n3PUFA had mean AFCs of 11.9, 13.2 and 14.1, respectively, across increasing tertiles of hair Hg (p,trend = 0.004). Similar results were found when hair Hg was divided above vs below EPA reference (mean AFC = 12.7 vs. 14.1, p = 0.008).

CONCLUSIONS

In these women, positive associations of hair Hg with AFC may be reflective of beneficial effects of n3PUFA on ovarian reserve rather than a beneficial effect of Hg per se. Our findings highlight the importance of considering diet when exploring Hg effects on women's reproductive health in urban settings.

Can Nutrition Help in the Treatment of Infertility?

Infertility is defined as the inability to conceive after 12 months of unprotected intercourse or six months for women aged 35 years or older. The physical, emotional, psychological, and financial statuses of infertile couples are tremendously affected especially after undergoing diagnostic and/or curative treatments. Human fertility is influenced by multiple factors including female or male, and modifiable or non-modifiable factors. There is growing evidence that nutri-tion may play an important role in adjusting fertility-related outcomes in both men and women. The objective of our study was to summarize the latest data on nutritional factors (specific food groups, nutrients, and nutritional supplements) that have an impact on female or male sexual and reproductive function. PubMed and Google Scholar platforms were used to collect appropriate articles for the review using several combinations of keywords (infertility, diet, dietary supplements, antioxidants, and beverages). Adherence to a healthy dietary pattern favoring fish, poultry, whole grains, fruits, vegetables, and healthy fats, was related to better fertility in both genders. Despite the multifactorial etiology of sexual infertility, nutrition may affect the sexual/reproductive function in both women and men.

Unraveling the Balance between Genes, Microbes, Lifestyle and the Environment to Improve Healthy Reproduction

Humans’ health is the result of a complex and balanced interplay between genetic factors, environmental stimuli, lifestyle habits, and the microbiota composition. The knowledge about their single contributions, as well as the complex network linking each to the others, is pivotal to understand the mechanisms underlying the onset of many diseases and can provide key information for their prevention, diagnosis and therapy. This applies also to reproduction. Reproduction, involving almost 10% of our genetic code, is one of the most critical human’s functions and is a key element to assess the well-being of a population. The last decades revealed a progressive decline of reproductive outcomes worldwide. As a consequence, there is a growing interest in unveiling the role of the different factors involved in human reproduction and great efforts have been carried out to improve its outcomes. As for many other diseases, it is now clear that the interplay between the underlying genetics, our commensal microbiome, the lifestyle habits and the environment we live in can either exacerbate the outcome or mitigate the adverse effects. Here, we aim to analyze how each of these factors contribute to reproduction highlighting their individual contribution and providing supporting evidence of how to modify their impact and overall contribution to a healthy reproductive status.

Complementary and Alternative Medicine for Threatened Miscarriage: Advantages and Risks

Threatened miscarriage is one of the most common complications causing pregnancy loss, and it affects approximately 20% of confirmed pregnancies. More and more women are seeking treatment with complementary and alternative medicine (CAM) for this common complication, and it has been reported that women have had successful pregnancies after threatened miscarriage when being treated with CAM, which mainly includes Chinese herbal medicines, acupuncture, and nutritional supplements as well as psychological interventions and other approaches. However, many experts are concerned about the safety and adverse events of certain CAM approaches in women with threatened miscarriage. Therefore, this review focuses on the status of CAM for threatened miscarriage and presents the potential therapeutic efficacy and safety of CAM based on some clinical and experimental studies. We thus hope to provide some instructive suggestions for the application of CAM for treating threatened miscarriage in the future.

Electronic Cigarettes and Fecundability: Results From a Prospective Preconception Cohort Study

Although electronic cigarette (e-cigarette) aerosol contains similar toxicants to combustible cigarettes, few studies have examined their influence on fecundability. We assessed the association between e-cigarette use and fecundability, overall and according to combustible cigarette smoking history, in a cohort of 4,586 North American women (aged 21-45 years) enrolled during 2017-2020 in Pregnancy Study Online, a Web-based prospective preconception study. Women reported current and former e-cigarette use on baseline and follow-up questionnaires, and they completed bimonthly follow-up questionnaires until self-reported pregnancy or censoring. Fecundability ratios and 95% confidence intervals were calculated using proportional probabilities models, controlling for potential confounders. Overall, 17% of women had ever used e-cigarettes and 4% were current users. Compared with never use of e-cigarettes, current e-cigarette use was associated with slightly lower fecundability (fecundability ratio = 0.84, 95% confidence interval (CI): 0.67, 1.06). Compared with current nonusers of e-cigarettes and combustible cigarettes, fecundability ratios were 0.83 (95% CI: 0.54, 1.29) for current dual users of e-cigarettes and combustible cigarettes, 0.91 (95% CI: 0.70, 1.18) for current e-cigarette users who were nonsmokers of combustible cigarettes, and 1.01 (95% CI: 0.85, 1.20) for nonusers of e-cigarettes who were current smokers of combustible cigarettes. Current e-cigarette use was associated with slightly reduced fecundability, but estimates of its independent and joint associations with combustible cigarette smoking were inconsistent and imprecise.

Milk and Dairy Products and Their Impact on Carbohydrate Metabolism and Fertility-A Potential Role in the Diet of Women with Polycystic Ovary Syndrome

Milk and dairy products are considered an important component of healthy and balanced diet and are deemed to exert a positive effect on human health. They appear to play a role in the prevention and treatment of carbohydrate balance disturbances. The products include numerous valuable components with a potential hypoglycemic activity, such as calcium, vitamin D, magnesium and probiotics. Multiple authors suggested that the consumption of dairy products was negatively associated with the risk of type 2 diabetes mellitus, insulin resistance and ovulation disorders. However, there are still numerous ambiguities concerning both the presumed protective role of dairy products in carbohydrate metabolism disorders, and the advantage of consuming low-fat dairy products over high-fat ones, especially in women with the risk of ovulation disorders. Therefore, this literature review aims at the presentation of the current state of knowledge concerning the relationship between dairy product consumption and the risk of insulin resistance, type 2 diabetes mellitus in women, and the potential effect on the course of polycystic ovary syndrome.

The Association between Seafood Intake and Fecundability: Analysis from Two Prospective Studies

Background: Seafood is an important source of omega-3 fatty acids, which have been associated with improved oocyte quality and embryo morphology in some studies. However, seafood is also a source of persistent organic pollutants and heavy metals, which may adversely affect fecundity. Previous studies of seafood intake and fecundity have generated inconsistent results. Methods: In two prospective cohort studies of 7836 female pregnancy planners from Denmark (Snart Foraeldre, n = 2709) and North America (PRESTO, n = 5127), we evaluated the association of dietary intake of total seafood and marine-sourced long-chain omega-3 fatty acids (eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid) with fecundability. Participants completed a baseline questionnaire on sociodemographics, behavioral factors, anthropometrics, and medical history, and a food frequency questionnaire. Pregnancy status was updated bimonthly for up to 12 months or until reported conception. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) using proportional probabilities regression models, adjusted for energy intake and other potential confounders. We restricted analyses to women with ≤6 menstrual cycles of attempt time at enrollment. Results: Intake of total seafood or marine-sourced long-chain omega-3 fatty acids was not appreciably associated with fecundability in either cohort (≥200 vs. <50 g/week total seafood: FR = 0.94, 95% CI: 0.79–1.10 in Snart Foraeldre; FR = 1.00, 95% CI: 0.90–1.13 in PRESTO; marine fatty acids: ≥90th vs. <25th percentile: FR = 1.00, 95% CI: 0.85–1.18 in Snart Foraeldre; FR = 0.97, 95% CI: 0.86–1.09 in PRESTO). In PRESTO, where we collected additional data on seafood preparation, we observed an inverse association between fecundability and fried shellfish (≥10 g/week vs. none: FR = 0.77, 95% CI: 0.61–0.98), but not unfried shellfish (≥20 g/week vs. none: FR = 0.98, 95% CI: 0.89–1.07); in Snart Foraeldre, there was no association with total shellfish intake. Conclusions: We found little association between seafood intake and fecundability overall, but greater intake of fried shellfish was associated with reduced fecundability among North American participants.

Relationship between nutrition and reproduction

BACKGROUND

Recently, the relationship between nutrition and reproduction is being studied. In particular, when older women receive reproductive treatment, egg aging causes greater problems than organic factors.

METHODS

This study investigated the relationship between nutrition and reproduction with a focus on factors that cause aging, including oxidation, glycation, and chronic inflammation. A large volume of data concerning each nutrient's relationship with reproductive medicine was collected from a number of observational studies.

MAIN FINDINGS

The results showed that refined carbohydrates should be avoided and care should be taken to achieve proper intake of omega-3 fatty acids. Folic acid and vitamin D were also effective. For men, antioxidant measures are especially effective. The effects of antioxidants are related to insulin resistance, which causes chronic inflammation.

CONCLUSION

Recent research has shown that rather than meal content, meal intervals are more important for improving insulin resistance. Future research should examine lifestyle-related nutrition factors and their relationships to reproductive treatment.

Emerging Trends in Research on Food Compounds and Women’s Fertility: A Systematic Review

Pro-healthy behaviours, including the diet, are significant factors in maintaining women’s fertility health. However, to improve the patient’s nutrition management, it is important to seek food-derived bioactive compounds to support fertility treatment. This review analysed recent studies of food compounds related to fertility, using databases including PubMed, Web of Science and Science Direct as well as PRISMA (preferred reporting items for systematic reviews) to ensure complete and transparent reporting of systematic reviews. This review lists foods associated with a higher birth rate, using original papers from the last five years (2015). The analysis included the impact of food compounds such as caffeine, fatty acids, folates and vitamin D, as well as the intake of fish, whole grains, dairy and soya. In addition, dietary patterns and total diet composition supporting women’s fertility were also analysed. The results will encourage further research on the relationship between food components and fertility.

Defining preconception: exploring the concept of a preconception population

Background

Health prior to conception can significantly impact offspring health, however, a clear definition of the attributes of the preconception population is currently lacking. We aimed to use existing literature to explore the concept and attributes of a preconception population by: [1] identifying characteristics and research recruitment methods; and [2] generating an attribute-based working definition of a preconception population.

Methods

A rapid review of current literature using CINAHL and the subject heading ‘pre-pregnancy care’ was conducted (Stage 1). Data extracted included definitions of preconception, participant inclusion/exclusion criteria, participant characteristics, and recruitment methods. Stage 2 involved a wider search of relevant publications beyond peer-reviewed literature followed by a concept analysis of the phrase “preconception population” applying Walker and Avant’s framework (Stage 2).

Results

Twenty-three papers (19 studies) were included in Stage 1. “Preconception” was explicitly defined in one study. Twelve studies specified participants must be planning a pregnancy. Stage 2 included 33 publications. Four key perspectives for the concept of the preconception population were derived: [1] intentional; [2] potential; [3] public health; and [4] life course.

Conclusions

Adopting these perspectives may allow researchers to accurately define, identify and recruit preconception populations and to develop interventions that are appropriately broad or tailored depending on population needs. We hope the definitions will facilitate research with this population and will subsequently improve the wellbeing of preconception men and women, which is essential to ensuring the health of future generations.

Serum omega-3 and omega-6 fatty acid concentrations and natural fertility

STUDY QUESTION

Are serum omega-3 and omega-6 essential fatty acid concentrations associated with the probability of conceiving?

SUMMARY ANSWER

There is no strong association between serum concentrations of omega-3 and omega-6 fatty acids and the probability of conceiving naturally.

WHAT IS KNOWN ALREADY

Omega-3 and omega-6 fatty acid serum concentrations have been shown to play an important role in reproduction in animal models, while conflicting results have been reported in human studies of infertile women. It is unknown to what extent omega fatty acid serum concentrations impact natural fertility.

STUDY DESIGN, SIZE, DURATION

A nested, case-control study was conducted consisting of 200 participants [fertile: conceived within 3 cycles of attempt (n = 50), subfertile: conceived within 4 and 12 cycles of attempt (n = 100) and infertile: did not conceive within 12 cycles of attempt (n = 50)] randomly selected from the Time to Conceive cohort, a prospective time-to-pregnancy study (2008 to 2015).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the Time to Conceive study, women aged 30-44 years who were trying to conceive for <3 months and had no history of infertility were recruited and followed until the end of their pregnancy or ~1 year of pregnancy attempt. For this study, serum collected early in the woman's pregnancy attempt was analysed for anti-Müllerian hormone (AMH) and omega-3 and omega-6 fatty acid concentrations by liquid chromatography-mass spectrometry. The primary outcome was a positive home pregnancy test. The secondary outcomes were miscarriage and serum AMH level. A discrete-time Cox proportional hazards model was used to estimate the fecundability ratio. The odds ratios for miscarriage were calculated using logistic regression. The association between serum omega fatty acid concentrations and AMH level (natural log transformed) was analysed using Pearson's Correlation.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 200 women provided 1321 cycles for analysis.Mean omega-3, omega-6 and omega-6:omega-3 ratios did not significantly differ between the fertile, subfertile and infertile groups. There were no associations (all fecundability ratios ~1.0) between pregnancy and individual omega-3 fatty acid concentrations, including alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid, or omega-6 fatty acids, including linoleic acid (LA), dihommo-gamma linolenic acid and arachidonic acid. There was no significant association between any individual omega fatty acid serum concentration and the age-adjusted odds of miscarriage. No association was found between any serum omega fatty acid concentration and AMH.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by the sample size. Omega-3 and omega-6 fatty acid concentrations were derived from serum provided at a single timepoint in the first cycle of enrollment. Serum concentrations may therefore not be representative of all critical timepoints in the menstrual cycle or throughout their attempts to conceive. Additionally, women enrolled in this study were 30 years of age and older, and therefore the findings may not apply to younger women.

WIDER IMPLICATIONS OF THE FINDINGS

These data would suggest that omega-3 and omega-6 serum levels are not associated with natural fertility or risk of miscarriage. However, due to the above-mentioned limitations, future investigation is still needed to determine whether omega-3 fatty acid supplementation may benefit women planning to conceive naturally.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Division of Reproductive Endocrinology and Infertility at the University of North Carolina at Chapel Hill, by the NIH/NICHD (R21 HD060229-01 and R01 HD067683-01) and, in part, by the Intramural Research Program of the National Institute of Environmental Health Sciences (Z01ES103333). Dr. Jukic received vitamin D supplements for a research study from Theralogix, Inc. The authors have no other conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

N/A.

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.

High-fat diet-induced dysregulation of ovarian gene expression is restored with chronic omega-3 fatty acid supplementation

Chronic high-fat diet (HFD) consumption causes ovarian dysfunction in rodents. Acute dietary treatment with docosahexaenoic acid (DHA) increases oocyte quality and ovarian reserve at advanced reproductive age. We hypothesized that DHA supplementation after HFD exposure reverses HFD-induced ovarian defects. We conducted a dietary intervention with reversal to chow, DHA-supplemented chow, or DHA-supplemented HFD after HFD consumption. After 10 weeks, HFD-fed mice had impaired estrous cyclicity, decreased primordial follicles, and altered ovarian expression of 24 genes compared to chow controls. Diet reversal to either chow or chow + DHA restored estrous cyclicity, however only chow + DHA appeared to mitigated the impact of HFD on ovarian reserve. All dietary interventions restored HFD-dysregulated gene expression to chow levels. We found no association between follicular fluid DHA levels and ovarian reserve. In conclusion our data suggest some benefit of DHA supplementation after HFD, particularly in regards to ovarian gene expression, however complete restoration of ovarian function was not achieved.

Preconception blood pressure and time to pregnancy among couples attempting to conceive their first pregnancy

BACKGROUND

The association of abnormal blood pressure levels (including hypertension and prehypertension) with reduced fecundability among young childbearing-age couples is not yet elucidated completely.

OBJECTIVE

The purpose of this study was to investigate the association between abnormal preconception blood pressure level and time to pregnancy among couples who are attempting to conceive their first pregnancy.

STUDY DESIGN

A total of 2,234,350 eligible couples (with no previous gravidity and whose female partners were 20-49 years old) participated in the National Free Preconception Check-up Projects from January 1, 2015, to December 31, 2016. Each couples' preconception blood pressure levels were measured, and time to pregnancy was recorded. Cox models for discrete survival time were used to estimate fecundability odds ratios and their corresponding 95% confidence intervals after adjustment for age, ethnicity, educational level, occupation, household registration, region, tobacco exposure, alcohol intake, body mass index, duration of marriage of the couples, and fasting plasma glucose levels of the female partner.

RESULTS

Compared with normotensive women, those women with hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg) had a 21% lower pregnancy rate (fecundability odds ratio, 0.79; 95% confidence interval, 0.78-0.81). A similar finding was found among men (fecundability odds ratio, 0.89; 95% confidence interval, 0.88-0.90). Prehypertension (systolic blood pressure between 120 and 139 mm Hg, and/or a diastolic blood pressure between 80 and 89 mm Hg) in both male and female partners was associated slightly with reduced fecundability odds ratios. Compared with couples in which both partners were normotensive, the pregnancy rate was reduced by 27% (fecundability odds ratio, 0.73; 95% confidence interval, 0.69-0.77) among couples in which both partners had hypertension.

CONCLUSION

Abnormal preconception blood pressure levels were associated with prolonged time to pregnancy among couples who were attempting to conceive their first pregnancy; the mechanism is worth further investigation.

Increasing the Chances of Natural Conception: Opinion Statement from the the Brazilian Federation of Gynecology and Obstetrics Associations - FEBRASGO - Committee of Gynecological Endocrinology

Considering that myths and misconceptions regarding natural procreation spread rapidly in the era of easy access to information and to social networks, adequate counseling about natural fertility and spontaneous conception should be encouraged in any kind of health assistance. Despite the fact that there is no strong-powered evidence about any of the aspects related to natural fertility, literature on how to increase the chances of a spontaneous pregnancy is available. In the present article, the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO, in the Portuguese acronym) Committee on Endocrine Gynecology provides suggestions to optimize counseling for non-infertile people attempting spontaneous conception.

Diet and female fertility: doctor, what should I eat?

Fecundity is the capacity to produce offspring. Identifying dietary factors that influence human fecundity is of major clinical and public health significance. This review focuses on the evidence from epidemiologic literature for the relationships between key nutritional factors and female reproductive potential. According to existing data, women trying to achieve pregnancy are encouraged to increase consumption of whole grains, omega-3 fatty acids, fish, and soy and to reduce consumption of trans fats and red meat. In addition, a daily multivitamin that contains folic acid before and during pregnancy may not only prevent birth defects, but also improve the chance of achieving and maintaining a pregnancy. In contrast, there is limited evidence supporting an association between vitamin D and human fecundity outcomes despite promising evidence from nonhuman studies. Questions for future research included the roles of other types of fat (especially omega-6 and monounsaturated fats) and protein (especially white meat and seafood) on female fertility; particular attention should also be paid to exposure to environmental contaminants in foods. Although much work remains, this review accrued best available evidence to provide practical dietary recommendations for women trying to conceive.

Reduction in FSH Throughout the Menstrual Cycle After Omega-3 Fatty Acid Supplementation in Young Normal Weight but not Obese Women

Dietary fish oil restores ovarian function in subfertile rats, which is thought to be associated with decreased transcription of follicle-stimulating hormone (FSH) β-subunit. We have previously demonstrated a reduction in early follicular serum FSH levels in normal weight but not obese women after treatment with omega-3 polyunsaturated fatty acids (PUFA). Herein, we report the effect of supplementation with omega-3 PUFA on urinary reproductive hormones across the whole menstrual cycle. This interventional study included 17 eumenorrheic women, aged 24-41 years. One month of daily morning urine was collected before and after 1 month of omega-3 PUFA supplementation with 4 g of eicosapentaenoic acid and docosahexaenoic acid daily. Measurements included urinary FSH, luteinizing hormone (LH) and estrogen and progesterone metabolites, plasma fatty acid composition, and markers of endoplasmic reticulum stress. Compliance with dietary supplementation was verified by significantly reduced ratios of omega-6 to omega-3 PUFA for all subjects after treatment (P < .01). After 1 month of omega-3 PUFA supplementation, urinary FSH was significantly decreased in normal weight, but not obese women, in both follicular and luteal phases (-28.4% and -12.6%, respectively, both P = .04). No significant changes were seen in LH or sex steroids for either weight group. The selective and specific decrease in FSH suggests that omega-3 PUFA supplementation merits further investigation in normal weight women with decreased fertility and/or diminished ovarian reserve.

Serum omega-3 fatty acids and treatment outcomes among women undergoing assisted reproduction

STUDY QUESTION

Are serum polyunsaturated fatty acids (PUFA) concentrations, including omega-3 (ω3-PUFA) and omega-6 (ω6-PUFA), related to ART outcomes?

SUMMARY ANSWER

Serum levels of long-chain ω3-PUFA were positively associated with probability of live birth among women undergoing ART.

WHAT IS KNOWN ALREADY

Intake of ω3-PUFA improves oocyte and embryo quality in animal and human studies. However, a recent cohort study found no relation between circulating ω3-PUFA levels and pregnancy rates after ART.

STUDY DESIGN SIZE, AND DURATION

This analysis included a random sample of 100 women from a prospective cohort study (EARTH) at the Massachusetts General Hospital Fertility Center who underwent 136 ART cycles within one year of blood collection.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Serum fatty acids (expressed as percentage of total fatty acids) were measured by gas chromatography in samples taken between Days 3 and 9 of a stimulated cycle. Primary outcomes included the probability of implantation, clinical pregnancy and live birth per initiated cycle. Cluster-weighted generalized estimating equation (GEE) models were used to analyze the association of total and specific PUFAs with ART outcomes adjusting for age, body mass index, smoking status, physical activity, use of multivitamins and history of live birth.

MAIN RESULTS AND ROLE OF CHANCE

The median [25th, 75th percentile] serum level of ω3-PUFA was 4.7% [3.8%, 5.8%] of total fatty acids. Higher levels of serum long-chain ω3-PUFA were associated with higher probability of clinical pregnancy and live birth. Specifically, after multivariable adjustment, the probability of clinical pregnancy and live birth increased by 8% (4%, 11%) and 8% (95% CI: 1%, 16%), respectively, for every 1% increase in serum long-chain ω3-PUFA levels. Intake of long-chain ω3-PUFA was also associated with a higher probability of life birth in these women, with RR of 2.37 (95% CI: 1.02, 5.51) when replacing 1% energy of long-chain ω3-PUFA for 1% energy of saturated fatty acids. Serum ω6-PUFA, ratios of ω6 and ω3-PUFA, and total PUFA were not associated with ART outcomes.

LIMITATIONS REASONS FOR CAUTION

The generalizability of the findings to populations not undergoing infertility treatment may be limited. The use of a single measurement of serum fatty acids to characterize exposure may lead to potential misclassification during follow up.

WIDER IMPLICATIONS OF THE FINDINGS

Serum ω3-PUFA are considered biomarkers of dietary intake. The association of higher serum long chain ω3-PUFA levels with improved ART outcomes suggests that increased intake of these fats be may be beneficial for women undergoing infertility treatment with ART.

STUDY FUNDING/COMPETING INTERESTS

NIH grants R01-ES009718 from the National Institute of Environmental Health Sciences, P30-DK046200 and T32-DK007703-16 from the National Institute of Diabetes and Digestive and Kidney Diseases, and L50-HD085359 from the National Institute of Child Health and Human Development, and the Early Life Nutrition Fund from Danone Nutricia US. Dr Rueda is involved in a patent 9,295,662, methods for enhancing, improving, or increasing fertility or reproductive function (http://patents.com/us-9295662.html). This patent, however, does not lead to financial gain for Dr Rueda, or for Massachusetts General Hospital. Dr Rueda does not own any part of the company nor does he have any equity in any fertility related company. As Dr Rueda is not a physician, he does not evaluate patients or prescribe medications. All other coauthors have no conflicts of interest to declare.