Dietary patterns and difficulty conceiving: a nested case-control study

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.

Role of Mediterranean diet in endocrine diseases: a joint overview by the endocrinologist and the nutritionist

PURPOSE

The purpose of this review is to examine the current evidence on the potential role of Mediterranean diet (MD) in the prevention and management of endocrine disorders and to highlight the importance of interdisciplinary collaboration between endocrinologists and nutritionists.

METHODS

A literature search was conducted using PubMed and Google Scholar databases to identify relevant studies published in English. Studies were selected based on their relevance to the role of MD in the prevention and management of endocrine disorders. The search terms included "Mediterranean diet," "endocrine disorders," "thyroid disorders," "gonadal disorders," and "neuroendocrine tumors".

RESULTS

The studies reviewed suggest that MD may have a beneficial effect in the prevention and management of various endocrine disorders, including thyroid disorders, gonadal disorders, and neuroendocrine tumors. MD has been associated with decreased risk of nodular thyroid disease and thyroid cancer, improved male and female reproductive health, and a potential role in the management of neuroendocrine tumors. MD's anti-inflammatory and antioxidant properties, as well as its high levels of phytochemicals, may play a role in its beneficial effects.

CONCLUSION

Interdisciplinary collaboration between endocrinologists and nutritionists is essential for the optimal management of endocrine disorders, including the potential role of MD in their prevention and management. While further research is needed, the current evidence suggests that MD may have a protective effect against endocrine disorders, and its incorporation into dietary recommendations may be beneficial.

Mediterranean diet and female reproductive health over lifespan: a systematic review and meta-analysis

OBJECTIVE

We conducted a systematic review and meta-analysis of the effects of Mediterranean diet on female reproductive health outcomes over the life-course.

DATA SOURCES

We searched PubMed, Embase, MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov to identify eligible studies published till February 2022. Eligible references from identified studies and review articles were also considered.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials, prospective cohort studies, or nested case-control studies examining Mediterranean diet and major female reproductive outcomes over the lifespan, including clinical outcomes from childhood to adulthood (menarche, polycystic ovary syndrome, endometriosis, and outcomes related to fertility, pregnancy, and menopause), were included for review.

METHODS

Two independent reviewers screened and performed data extraction and risk-of-bias assessment. We performed random-effects meta-analysis to obtain summary relative risks and 95% confidence intervals for major female reproductive outcomes. Subgroup analyses were performed for several pregnancy outcomes according to timing of the interventions for randomized controlled trials and timing of the dietary assessment for observational studies.

RESULTS

Thirty-two studies (9 randomized controlled trials, 22 prospective cohort studies, and 1 nested case-control study) involving 103,204 predominantly White women (>95%) were included. The pooled relative risk (95% confidence interval) comparing randomization to Mediterranean diet vs a control diet based on 7 randomized controlled trials was 0.74 (0.55-0.99) for gestational diabetes mellitus, 0.45 (0.26-0.76) for preterm birth, 0.71 (0.51-1.00) for gestational hypertension, and 0.82 (0.54-1.22) for preeclampsia; the effect sizes for preterm birth were greater in randomized controlled trials that initiated the interventions in first trimester vs after first trimester (P heterogeneity=.02). We observed inverse associations for all the above-mentioned pregnancy outcomes based on 9 cohort studies. There was suggestive evidence of favorable associations between Mediterranean diet adherence with fertility and gestational weight management. Limited studies suggested associations between higher Mediterranean diet adherence and later time to menarche and fewer vasomotor menopausal symptoms, null associations for polycystic ovary syndrome-like phenotype and pregnancy loss, and positive associations for luteal phase deficiency.

CONCLUSION

Adherence to Mediterranean diet may lower risks of adverse pregnancy outcomes among predominantly White populations. For fertility-related outcomes, available evidence supporting potential beneficial effects is suggestive yet limited. For other reproductive outcomes across the lifespan, data remains sparse.

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.

A Literature Review and a Proposed Classification of the Relationships between Ovulatory Infertility and Lifestyle Factors Based on the Three Groups of Ovulation Disorders Classified by WHO

Ovulatory infertility is a serious clinical problem whose direct causes are still largely unknown. In addition to pathologies that make it impossible for a couple to establish a pregnancy, there are a number of other factors that have a bearing on fertility, including lifestyle factors, and particularly diet. Although numerous studies have been performed linking such factors to ovulatory infertility, most of them lack the necessary clinical significance, instead focusing on observational data and suggesting or establishing associative relationships. This article consists of a literature review focusing on connections between lifestyle factors such as diet, physical exercise, oxidative stress, sleep, and supplementation, and ovulatory infertility. Special emphasis was given to issues such as obesity and insulin resistance and their mutual relationship with other factors linked to ovulatory infertility. In addition, based on the conclusions of the literature review, the authors have proposed a classification of relationships between ovulation disorders and lifestyle factors in ovulatory infertility within the framework of the WHO classification of ovulation disorders. Furthermore, areas that merit further research have been indicated as well as those that do not. WHO Group II disorders gained prominence in the results of the study as the number of links with lifestyle factors and ovulatory infertility found in the course of the review greatly exceeded those for Groups I and III. The data presented in the article show that the issues of proper diet and physical exercise are those that could benefit from robust clinical studies focused specifically on ovulation infertility, while studies concerning the relationship between oxidative stress, sleep, and supplementation and ovulatory infertility do not seem to be promising directions as far as clinical significance is concerned.

The Effect of Metabolic Persian Diet on Ovulation Induction in Infertile Women

Introduction

Infertility is an important issue with a high social and psychological burden. From the perspective of Persian Medicine (PM), uterine cold temperament is one of the important causes of female infertility.

Aim

The aim of this study was to study the effect of PM or Iranian traditional medicine on improving ovulation and fertility.

Methods

From January 2017 to August 2017, sixty infertile women with eugonadotropic ovulation disorder were randomly divided into two groups. Both groups were treated with clomiphene citrate, except that the intervention group also received metabolic Persian diet (MPD). In each cycle, the dominant follicles and endometrium were investigated with ultrasound. At the end of the cycle, beta human chorionic gonadotropin (β-HCG) was evaluated and if positive, another ultrasound was performed two weeks later to confirm early pregnancy.

Results

The number of dominant follicles from the first to third cycle increased from 2.15 ± 1.14 to 2.28 ± 0.61 in the intervention group and decreased from 1.86 ± 0.79 to 1.30 ± 0.47 in the control group. The dominant follicle size changed from 16.00 ± 4.08 to 18.78 ± 2.78 and from 15.05 ± 3.11 to 15.80 ± 3.89 in the intervention and control groups, respectively. But endometrial thickness did not change significantly in the intervention group. Pregnancy results based on β-HCG and ultrasound findings were positive in 19 and 16 patients in the intervention group and in 10 and 7 patients in the control group, implying significantly higher numbers in the first group.

Conclusion

It seems that MPD may be effective in the success of ovulation induction.

Integrative medicine utilization among infertility patients

BACKGROUND

Previous research suggests that some women are using integrative and complementary holistic approaches to optimize their own health and treat infertility. We aimed to determine patterns of integrative medicine use among those seeking fertility optimization by 1) Characterizing patterns of integrative medicine use to increase fertility; 2) Identifying demographic predictors associated with such integrative medicine use; and 3) Exploring cultural and religious influences on use of integrative medicine.

METHODS

Cross-sectional self-reported survey data were collected from 1460 patients presenting to an academic fertility center in Chicago, Illinois. Variables were described with univariate frequencies and proportions, unadjusted bivariate comparisons were made between patient-level factors and reported integrative modality use, and multivariable logistic regression evaluated the strength of covariate-adjusted predictors of reported integrative medicine utilization.

RESULTS

80.4% of respondents reported using at least one integrative medicine modality to treat infertility (Acupuncture: 38.5%, Yoga: 27.6%, Massage: 25.8%, Meditation: 16.7%, and Herbal supplements: 18.5%). Diet therapy was the most frequently utilized modality (74.0%) followed by body therapy (45.2%), traditional alternative medicine (42.0%), mind therapy (32.1%), and senses therapy (23.0%). Any integrative medicine modality use was 4.03 times more likely among Hindu respondents compared to participants that identified as not religious (95% CI 1.2-13.7, p < 0.026). Significant differences in specific modality use were observed by race, religious affiliation, age, income, and insurance coverage.

CONCLUSION

Most infertility patients in our study reported using at least one integrative medicine modality to help them conceive. Utilization was associated with age of participant, religious affiliation, annual income, and insurance coverage. Further research is needed to assess the impact of integrative medicine utilization on patient quality of life and outcomes.

Adherence to the Mediterranean diet and the risk of unexpected poor response to ovarian stimulation in IVF cycles

RESEARCH QUESTION

Can preconception adherence to a Mediterranean diet influence the rate of poor response to ovarian stimulation in IVF cycles?

DESIGN

The impact of dietary habits on the success of IVF is controversial. Inconsistencies may be explained by confounders associated with the use of pregnancy as an outcome as well as by a reductionist view of diet that focuses on single components rather than on food patterns. This cross-sectional study analysed adherence to a Mediterranean diet in women with unexpected poor response to ovarian stimulation. Main inclusion criteria were: age 18-39 years, normal weight, preserved ovarian reserve and starting dose of gonadotrophins of 150-225 IU/day. Adherence to the Mediterranean diet was assessed through a Mediterranean diet score (MDS). Unexpected poor ovarian response was defined as the retrieval of ≤3 suitable oocytes.

RESULTS

A total of 296 women were included, of whom 47 (15.9%) showed an unexpected poor response. A clear dose-related association with tertiles of MDS was not observed in the univariate analysis. However, in the multivariate analysis, the risk of unexpected poor response was significantly lower for women in the second tertile of MDS compared with the first tertile (adjusted odds ratio [OR] 0.29, 95% confidence interval [CI] 0.11-0.76) and for women in the second and third tertiles, grouped together, compared with the first tertile (adjusted OR 0.34, 95% CI 0.14-0.82).

CONCLUSIONS

Low adherence to a Mediterranean diet could be a risk factor for unexpected poor ovarian response.

Characterization and risk factors for unexplained female infertility in Sudan: A case-control study

BACKGROUND

Female infertility with unknown causes (unexplained) remains one of the mysteries in the reproductive health field, where the diagnostic evidence is still weak and the proposed treatments still work with unknown methods. However, several studies have proposed some possible causes and risk factors for unexplained female infertility.

AIM

To characterize and identify factors associated with unexplained infertility in Sudanese women.

METHODS

A matched (age and body mass index) case-control study was conducted from March 2021 to February 2022. The study samples were 210 women with unexplained infertility (UI) and 190 fertile women of reproductive age who were attending the maternity hospitals and fertility clinics in Khartoum, Sudan. The risk factors of unexplained infertility were identified using a structured, pre-tested questionnaire containing information on socio-demographic variables, anthropometrics, clinical diagnosis of infertility, behavioral factors, physical activity assessment, diversity, and consumption of different food groups by the study participants.

RESULTS

The results showed a higher proportion of women diagnosed with UI were residents of rural areas than controls (21.4% vs 11.1%, P < 0.05), and previous miscarriages and/or abortions were more common in fertile women compared with infertile women (13.16% vs 5.71%, P < 0.05). Additionally, infertile women had a significantly (P < 0.05) higher proportion of family history of infertility (explained and unexplained) compared with controls. Finally, after controlling for the effects of potentially confounding variables using multivariable logistic regression analysis, only marital status, family history of infertility, use of modern contraceptives, smoking, caffeine consumption, physical activity level, meals consumed, other vitamin-A-rich fruits and vegetables, and other vegetables were found to be significant (P < 0.05) factors associated with unexplained infertility among Sudanese women.

CONCLUSION

Married women with a family history of infertility who smoke and consume a high amount of caffeine, who live a sedentary lifestyle, and who consume more than two meals free of vitamin-A-rich fruits and/or vegetables and/or other vegetables per day are at the highest risk of developing unexplained infertility.

The effect of dietary habits on oocyte/sperm quality

The effects of diet and nutritional habits on reproductive cells can be categorized in a variety of ways. In this review, the literature is divided, based on the dietary consumption effects on oocytes and sperm. Topics on dietary patterns and the intrauterine effect of maternal nutrition are covered. In general fruits, vegetables, whole greens, fish, legumes, and also dietary sources containing unsaturated fats can improve reproductive germ cell quality. In epidemiological studies, the food intake frequency questionnaire is one of the most common methods to assess diet. Due to methodological heterogeneity in dietary assessment and inadequacy in the measurement of dietary intake in the questionnaires used, several unreliable results may be reported. Thus, the quality of evidence needs to be improved, since nutritional diets may not be so simply objective and they are inadequate to explain obvious underlining mechanisms. In addition, various compounds that may be ingested can affect molecular mechanisms, influenced by other external factors (drugs, pesticides, smoking, alcohol) and changes in human nutritional parameters. Artificial Intelligence has recently gained widespread interest and may have a role in accurate analysis of dietary patterns for optimal nutritional benefit. Therefore, future prospective randomized studies and objective measurements, consisting of molecular level analysis of the impact on cells and clear-cut methods are needed for accurate assessment of the effect of dietary habits on reproductive treatment.

Can Dietary Patterns Impact Fertility Outcomes? A Systematic Review and Meta-Analysis

There are conflicting results on the effect of diet on fertility. This study aimed to assess the effect of different dietary patterns on fertility outcomes in populations who conceive spontaneously and those requiring assisted reproductive technology (ART). A systematic search and meta-analysis were performed for studies investigating dietary patterns or whole diets in reproductive aged women requiring ART or conceived naturally. Outcomes were live births, pregnancy rates and infertility rates. In amount of 15,396 studies were screened with 11 eligible studies. Ten different diet patterns were grouped broadly into categories: Mediterranean, Healthy or Unhealthy. For the Mediterranean diet, on excluding high risk-of-bias studies (n = 3), higher adherence was associated with improved live birth/pregnancy rates in ART [OR 1.91 (95% CI 1.14-3.19, I² 43%)] (n = 2). Adherence to various Healthy diets was associated with improved ART outcomes (ProFertility diet and Dutch Dietary Guidelines) and natural conception outcomes (Fertility diet). However, due to the variability in Healthy diets' components, results were not pooled. Studies demonstrated preliminary evidence for the role of dietary patterns or whole diets in improving pregnancy and live birth rates. However, due to heterogeneity across the literature it is currently unclear which diet patterns are associated with improvements in fertility and ART outcomes.

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.

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 patterns and fecundability in 2 prospective preconception cohorts

BACKGROUND

Diet is increasingly recognized as an important determinant of human fertility, with most research focused on specific nutrients or food groups. However, there has been limited assessment of the effect of dietary patterns on fertility.

OBJECTIVES

We evaluated the association between 4 dietary patterns [the alternative Mediterranean Diet (aMed), the Healthy Eating Index-2010 (HEI-2010), the Danish Dietary Guidelines (DDGI), and the Dietary Inflammatory Index (DII)] and fecundability in 2 preconception cohorts of couples trying to conceive: SF (SnartForaeldre.dk) in Denmark and PRESTO (Pregnancy Study Online) in North America.

METHODS

Participants completed a baseline questionnaire on sociodemographic, anthropometric, and lifestyle factors and, 10 d later, a validated cohort-specific FFQ. We used data from these respective FFQs to calculate adherence to each dietary pattern. Participants completed bimonthly follow-up questionnaires for ≤12 mo or until pregnancy, whichever came first. We restricted analyses to 3429 SF and 5803 PRESTO participants attempting pregnancy for ≤6 cycles at enrollment. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs, adjusting for potential confounders.

RESULTS

Greater DII, indicative of a less anti-inflammatory diet (i.e., poorer diet quality), was associated with reduced fecundability in both SF and PRESTO (DII ≥ -1.5 compared with < -3.3: FR: 0.83; 95% CI: 0.71, 0.97 and FR: 0.82; 95% CI: 0.73, 0.93, respectively). In PRESTO, greater adherence to the aMed or to the HEI-2010 was associated with greater fecundability. In SF, there was no appreciable association between the aMed and fecundability, whereas greater adherence to the DDGI was associated with greater fecundability.

CONCLUSIONS

In prospective preconception cohort studies from Denmark and North America, higher-quality diets, including diets lower in inflammatory effects, were associated with greater fecundability.

Periconceptional Mediterranean diet during pregnancy on children's health

During pregnancy, rapid and subtle physiological changes are observed from conception to birth. Nutrition and other lifestyle factors before and during pregnancy have been shown in the literature to influence the health of both mother and child. A healthy and varied diet during pregnancy can provide adequate energy and nutrients for both the mother and the growing fetus. Current research focuses on the periconceptional phase, which includes the early processes of gametogenesis, embryogenesis and placentation. A variety of abnormalities and pregnancy-related problems occur during this period, including congenital defects, fetal loss, miscarriage and preterm birth. A varied and balanced diet during periconception is important to maintain fetal development and growth. To date, numerous studies have been conducted to investigate the effects of consuming different nutrients, foods or food groups during pregnancy on the health of mother and child. For example, the Mediterranean diet is considered as a balanced, nutrient-rich diet due to the low consumption of meat products and fatty foods and the high consumption of vegetables, cheese, olive oil, fish, shellfish and little meat. While many studies have been conducted in the literature to investigate the effects of a Mediterranean diet during pregnancy on fetal health, the results have been inconclusive. The aim of this article is to review the current literature on the Mediterranean diet during pregnancy.

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.

Personalized Nutrition in the Management of Female Infertility: New Insights on Chronic Low-Grade Inflammation

Increasing evidence on the significance of nutrition in reproduction is emerging from both animal and human studies, suggesting a mutual association between nutrition and female fertility. Different “fertile” dietary patterns have been studied; however, in humans, conflicting results or weak correlations are often reported, probably because of the individual variations in genome, proteome, metabolome, and microbiome and the extent of exposure to different environmental conditions. In this scenario, “precision nutrition”, namely personalized dietary patterns based on deep phenotyping and on metabolomics, microbiome, and nutrigenetics of each case, might be more efficient for infertile patients than applying a generic nutritional approach. In this review, we report on new insights into the nutritional management of infertile patients, discussing the main nutrigenetic, nutrigenomic, and microbiomic aspects that should be investigated to achieve effective personalized nutritional interventions. Specifically, we will focus on the management of low-grade chronic inflammation, which is associated with several infertility-related diseases.

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.

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.

The relationship between overweight and female infertility

Excessive weight seems to negatively influence fertility, and as it is a modifiable factor, understanding this relationship can contribute to infertility treatment. Adipose tissue is responsible for releasing several hormones and cytokines related to the reproductive system, such as leptin, TNF-a, and Interleukin-6, substances that can negatively impact female fertility. Additionally, a woman's diet and lifestyle can influence body weight and fertility. Food consumption, characterized by a high intake of foods with high energy density, high levels of sugar, saturated fat, and poor nutrients, as well as physical inactivity, can favor excessive weight. Thus, losing body weight obtained through a healthy diet associated with physical activity may restore fertility in overweight women.

Influence of maternal and paternal pre-conception overweight/obesity on offspring outcomes and strategies for prevention

Overweight, obesity, and their comorbidities remain global health challenges. When established early in life, overweight is often sustained into adulthood and contributes to the early onset of non-communicable diseases. Parental pre-conception overweight and obesity is a risk factor for overweight and obesity in childhood and beyond. This increased risk likely is based on an interplay of genetic alterations and environmental exposures already at the beginning of life, although mechanisms are still poorly defined. In this narrative review, potential routes of transmission of pre-conceptional overweight/obesity from mothers and fathers to their offspring as well as prevention strategies are discussed. Observational evidence suggests that metabolic changes due to parental overweight/obesity affect epigenetic markers in oocytes and sperms alike and may influence epigenetic programming and reprogramming processes during embryogenesis. While weight reduction in overweight/obese men and women, who plan to become pregnant, seems advisable to improve undesirable outcomes in offspring, caution might be warranted. Limited evidence suggests that weight loss in men and women in close proximity to conception might increase undesirable offspring outcomes at birth due to nutritional deficits and/or metabolic disturbances in the parent also affecting gamete quality. A change in the dietary pattern might be more advisable. The data reviewed here suggest that pre-conception intervention strategies should shift from women to couples, and future studies should address possible interactions between maternal and paternal contribution to longitudinal childhood outcomes. Randomized controlled trials focusing on effects of pre-conceptional diet quality on long-term offspring health are warranted.

Effect of a dietary and exercise intervention in women with overweight and obesity undergoing fertility treatments: protocol for a randomized controlled trial

BACKGROUND

Distinct molecular, inflammatory, and metabolic signatures are present in oocytes and follicular fluid derived from women with obesity when compared to those derived from normal weight women, which suggest existing signals that may program future offspring for metabolic diseases. This study aims to assess the feasibility and efficacy of a peri-conception nutrition and exercise intervention on mitigating obesity-associated changes in oocyte gene expression profiles and follicular fluid metabolites.

METHODS

This single blinded randomized control trial will include 120 women with a BMI of 25-45 kg/m², ≥21 years of age, and undergoing in vitro fertilization (IVF) treatments. Participants will be randomized to standard of care (N = 60) or an intervention group (N = 60) in a block design by polycystic ovary syndrome status. The intervention will combine a dietary component (Mediterranean meal plan) with exercise prescription following the Physical Activity Guidelines for Americans. Participants will be assessed pre- and post-intervention. The standard of care group will be offered to join the intervention group if the IVF treatments are unsuccessful as a cross over design. Recruitment is anticipated to start in July of 2021. Primary outcomes will include single oocyte gene expression profiles and follicular fluid metabolites. Mann-Whitney U nonparametric tests will be used to assess potential differences for each stratum. Follicular fluid and serum metabolites will be analyzed using a one-factor Analysis of Covariance (ANCOVA) at four levels, pair-wise comparisons using Tukey-Kramer post-hoc tests will be used to identify groups whose means differ significantly while retaining the family-wise error rate at 5%. When the design is balanced, two-way Analysis of Variance (ANOVA), or non-parametric Friedman test will be used in data analysis. Additionally, general linear models and ANCOVA may be used to control for covariates. Significance will be set at p < 0.05. Findings will be disseminated via peer-reviewed manuscripts and presentations at scientific conferences.

DISCUSSION

This study will provide novel data and key information on the impact of a dietary and exercise intervention on oocyte gene expression and follicular fluid content. Results will demonstrate the potential of such intervention in mitigating obesity-induced changes in oocyte gene expression and follicular fluid metabolites.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT04273048 ): submitted November 13, 2019; posted February 17, 2020.

Maternal periconceptional nutrition matters. A scoping review of the current literature

BACKGROUND

The importance of nutrition in reproductive health is widely acknowledged with special emphasis given to periconceptional maternal diet and its implications on embryo-fetal development, pregnancy complications, and the health of the offspring.

METHODS

Following the PRISMA guidelines, we searched for literature in PubMed, CINAHL, and WoS to gather newer information on how diet composition influences the concepts from the very early stages of pregnancy and how maternal health may be affected as well. Fifty-six studies published up to June 2020 met the inclusion criteria.

RESULTS

With its proportioned and diversified macronutrient composition, the Mediterranean Diet prevents congenital anomalies, preterm birth, hypertensive disorders, and gestational diabetes. Similar dietary patterns rich in vegetables, nuts, fish, and cereals increase the likelihood of conception and have a protective action, mediated by their antioxidant properties, against orofacial clefts, congenital heart and limb defects in the progeny. Conversely, the pro-inflammatory features of western diets, rich in processed foods and low in fruit content, diminish fertility, increase miscarriage rates, and enhance the risk of neural tube defects regardless of folate supplementation.

CONCLUSIONS

It may be concluded that within the multiple dietary options, some of them are soundly associated with beneficial effects for the mother and the newborn.Implications for practiceAn appropriate counseling must be offered to the woman of fertile age to make her aware of how periconceptional nutrition may help fulfill her reproductive expectations.

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.

Dietary Approaches to Women's Sexual and Reproductive Health

Over the course of the reproductive life span, it is common for women to experience one or more of the most common gynecologic conditions, including sexual dysfunction, polycystic ovary syndrome, fibroids, endometriosis, and infertility. Although current management guidelines often turn to the established pharmaceutical approaches for each of these diagnoses, the scientific literature also supports an evidence-based approach rooted in the paradigm of food as medicine. Achieving healthy dietary patterns is a core goal of lifestyle medicine, and a plant-forward approach akin to the Mediterranean diet holds great promise for improving many chronic gynecologic diseases. Furthermore, creating an optimal preconception environment from a nutritional standpoint may facilitate epigenetic signaling, thus improving the health of future generations. This state-of-the-art review explores the literature connecting diet with sexual and reproductive health in premenopausal women.

Dietary Energy Density and Fertility: Results from the Lifestyle and Fertility Study

BACKGROUND

Diet is a modifiable lifestyle factor linked with fertility in a growing number of studies.

OBJECTIVE

The objective of this study was to evaluate the association between dietary energy density (ED), a summary measure of diet quality that estimates the amount of energy per unit food (kcal/g) consumed, and conception and pregnancy outcomes.

METHODS

A prospective cohort study of couples planning their first pregnancy was conducted in the Northeast region of the USA. Dietary data were collected prior to conception via 3 unannounced interviewer-administered 24-h dietary recalls. Multivariable-adjusted logistic regression (ORs and Cox proportional hazards models [RR] and 95% CIs) were estimated for continuous and categorical (tertile [T]) variables of dietary ED.

RESULTS

The majority of women (n = 80; 61%) achieved clinical pregnancy. Median time to conception of a clincal pregnancy(TTC) for those who conceived was 4.64 mo with an IQR of 4.37 mo. ED modeled as a continuous variable was not associated with clinical pregnancy, live birth, or TTC after controlling for race, physical activity, and male partner's ED. When ED was categorized to consider nonlinear associations, 60%, 73%, and 50% of the participants in the tertiles (from lowest ED to highest) achieved clinical pregnancy. In multivariable logistic analyses with the middle group as the referent (ED = 1.37-1.60), membership in the highest ED group (ED >1.60) was associated with lower odds of clinical pregnancy (OR = 0.30; 95% CI: 0.11, 0.81, P = 0.02). In Cox proportional hazards analyses, membership in the highest ED group was associated with significantly longer TTC compared with the middle category (HR = 0.41; 95% CI: 0.21,0.82, P = 0.01).

CONCLUSIONS

These results suggest that high dietary ED is associated with reduced fertility.This study evaluated associations between dietary energy density and the probability of conceiving clinical pregnancy, having a live birth, and the time to conception among couples planning pregnancy.

Associations between Maternal Dietary Patterns and Perinatal Outcomes: A Systematic Review and Meta-Analysis of Cohort Studies

The aim was to systematically review and meta-analyze prospective cohort studies investigating the relation between maternal dietary patterns during pregnancy with pregnancy and birth outcomes. PubMed, Scopus, and ISI Web of Science were searched from inception until October 2019 for eligible studies. Studies reporting relative risk, ORs, or incidences (for binary data) or means ± SDs or B-coefficients (for continuous outcomes) comparing the highest and lowest adherence with maternal dietary patterns were included. Dietary patterns were categorized as "healthy," "unhealthy," or "mixed." No language restrictions were applied. Study-specific effect sizes with SEs for outcomes of interest were pooled using a random-effects model. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Sixty-six relevant publications were included. A higher maternal adherence to a healthy diet was associated with a reduced risk of gestational hypertension (14%, P < 0.001), maternal depression (40%, P = 0.004), low birth weight (28%, P = 0.001), preterm birth (56%, P < 0.001), higher gestational weight gain (Hedges' g: 0.15; P = 0.01), and birth weight (Hedges' g: 0.19; P = 0.007). Higher maternal adherence to an unhealthy or a mixed diet was associated with higher odds of gestational hypertension (23%, P < 0.001 for unhealthy, and 8%, P = 0.01 for mixed diet). In stratified analyses, a higher healthy eating index was associated with reduced odds of being large based on gestational age (31%, P = 0.02) and a higher head circumference at birth (0.23 cm, P = 0.02). The Mediterranean and "prudent" dietary patterns were related to lower odds of being small based on gestational age (46%, P = 0.04) and preterm birth (52%, P = 0.03), respectively. The overall GRADE quality of the evidence for most associations was low or very low, indicating that future high-quality research is warranted. This study was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42018089756.

Association between dietary inflammatory index and inflammatory biomarkers with outcomes of in vitro fertilization treatment

AIM

To investigate associations between dietary inflammatory index (DII), high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) with outcomes of in vitro fertilization treatment.

METHODS

This observational prospective study included 144 women undergoing fresh in vitro fertilization cycles who attended infertility center of Al-Zahra Hospital in Tabriz, Iran. DII was computed based on dietary intake assessed using a 3-day 24-h food record diary. Outcomes of in vitro fertilization in this study were considered fertilization rate, embryo quality and positive pregnancy test. Inflammatory biomarkers were measured on the day of embryo transfer.

RESULTS

There was no statistically significant difference between pregnant and nonpregnant women in terms of infertility and demographic characteristics, quantity of retrieved and fertilized oocytes, fertilization rate and number of transferred embryos (P > 0.05). The mean quality scores of resultant embryos (P < 0.001) and transferred embryos (P = 0.019) were significantly lower in the group of pregnant women, indicating the better quality among them. Median (percentile 25-75th) DII in the pregnant women was 1.8 (0.5-2.7) and in the nonpregnant women was 1.6 (0.3-2.6). DII was significantly related to hs-CRP (r = 0.198, P = 0.017) but not to IL-6. There were no significant relationships between DII, serum hs-CRP, IL-6 and in vitro fertilization outcomes (P > 0.05).

CONCLUSION

These findings demonstrate that serum hs-CRP and IL-6 concentration and DII are not predictive markers of in vitro fertilization cycle outcomes in women undergoing in vitro fertilization.

A Priori and a Posteriori Dietary Patterns in Women of Childbearing Age in the UK

Poor diet quality is a major cause of maternal obesity. We aimed to investigate a priori and a-posteriori derived dietary patterns in childbearing-aged women in UK. An online survey assessed food intake, physical activity (PA), anthropometry and socio-demographics. An a priori defined diet quality was determined via Mediterranean diet (MD) adherence score and Exploratory Factor Analysis (EFA) derived dietary patterns (DPs). Multiple linear regression explored associations between DPs with anthropometric measures, PA and socio-demographics. Participants (n = 123) had low-to-medium MD adherence (average MD-score: 4.0 (2.0)). Age was positively associated with higher MD adherence (X2 (2) = 13.14, p = 0.01). EFA revealed three DPs: 'fruits, nuts, vegetables and legumes' ("Vegetarian-style" DP); 'sweets, cereals, dairy products and potatoes' ("Dairy, sweets and starchy foods" DP); and 'eggs, seafood and meats' ("Protein-rich" DP). "Vegetarian-style" DP was positively associated with higher maternal educational level (p < 0.01) and PA (p = 0.01), but negatively with white ethnicity (p < 0.01). "Dairy, sweets and starchy foods" DP was positively associated with white ethnicity (p = 0.03) and negatively with age (p = 0.03). "Protein-rich" DP was positively associated with age (p < 0.001) and negatively with PA (p = 0.01). A poor diet quality was found among childbearing-aged women; notably in the younger age category, those of white ethnicity, that were more physically inactive and with a lower socioeconomic background.

Dietary patterns and ovarian reserve among women attending a fertility clinic

OBJECTIVE

To investigate the associations between dietary patterns and antral follicle count (AFC), a marker of ovarian reserve.

DESIGN

Prospective cohort study.

SETTING

Fertility center at an academic hospital.

PATIENT(S)

A total of 363 women seeking preconception evaluation and infertility care at the Massachusetts General Hospital who participated in the Environment and Reproductive Health Study.

INTERVENTION(S)

None. At enrollment, women reported diet through a food frequency questionnaire, from which we computed three dietary pattern adherence scores: the Mediterranean diet, the Fertility diet, and the Profertility diet.

MAIN OUTCOME MEASURE(S)

The AFC was assessed with a transvaginal ultrasound performed on the third day of an unstimulated menstrual cycle or on the third day of a P withdrawal bleed.

RESULT(S)

Higher adherence to the three dietary patterns examined were unrelated to AFC. The multivariable adjusted AFC means and 95% confidence intervals for women in the highest compared with the lowest quartile of adherence score were 13.9 (13.0-14.9) and 13.5 (12.6-14.4) for the Mediterranean diet, 14.0 (13.2-14.9) and 13.5 (12.7-14.3) for the Fertility diet, and 12.5 (11.6-13.5) and 13.3 (12.5-14.2) for the Profertility diet.

CONCLUSION(S)

Dietary patterns were unrelated to AFC among a cohort of women presenting at a fertility center. Due to the limited and heterogeneous current evidence, it is important to evaluate this association in further studies, and in particular among women from the general population.

Obesity, Insulin Resistance, and Hyperandrogenism Mediate the Link between Poor Diet Quality and Ovarian Dysmorphology in Reproductive-Aged Women

The relationship between diet quality and ovarian morphology has biological plausibility yet remains unclear and was therefore evaluated. In a multicenter cross-sectional analysis, four dietary patterns were scored for 111 consecutive reproductive-aged women (18–45 years) using (1) Healthy Eating Index (HEI-2015); (2) alternative HEI-2010; (3) alternate Mediterranean Diet (aMED); (4) and Dietary Approaches to Stop Hypertension (DASH) indices. Ovarian volume (OV) and follicle number per ovary (FNPO) were evaluated on transvaginal ultrasonography. Relationships between dietary and ovarian morphology indices were evaluated by linear regression and mediation analyses. Associations between aMED and DASH scores and OV/FNPO were completely mediated by obesity, insulin resistance, and hyperandrogenism (All: p < 0.05), unlike direct associations (All: p ≥ 0.89). Namely, a 1-standard deviation [SD] increase in aMED score was associated with decreases in OV (0.09 SD; 0.4 mL) through reducing waist circumference. Likewise, a 1 SD increase in aMED and DASH score was associated with decreases in OV (0.07 SD; 0.3 mL) by reducing glucose response to a 75 g glucose tolerance test. A 1 SD increase in DASH score was associated with decreased FNPO (0.07 SD; 2 follicles) by reducing free androgen index (All: p < 0.05). Adherence to aMED and DASH eating plans was indirectly associated with significant improvements in ovarian form, providing novel mechanistic insights for future interventions about contributions of diet quality on ovarian function.

Mediterranean diet improves embryo yield in IVF: a prospective cohort study

BACKGROUND

Mediterranean diet (MediDiet) had been reported to be beneficial to human health. However the relationship between diet pattern and outcomes of in vitro fertilization (IVF) treatment was scarcely researched. This study was aimed to explore the correlation between MediDiet pattern of infertile women and their clinical outcomes of IVF cycles.

METHODS

An observational prospective cohort study was conducted in the reproductive center from September 2016 to December 2017. Seven hundred infertile women about to undergo IVF treatment were asked to conduct a questionnaire survey. Patients were assigned to higher MediDiet adherence group or lower MediDiet adherence group according to their Mediterranean diet scores. Laboratory parameters and clinical outcomes were compared and those were different between groups were further analyzed for their relationship with MediDiet adherence.

RESULTS

A total of 590 women were finally included in the study. According to MediDiet scores, 228 participants were categorized as higher MediDiet adherence group and 362 others as lower MediDiet adherence group. No significant differences were found in baseline characteristics between groups. Higher MediDiet adherence group showed larger number of embryos available (8.40 ± 5.26 vs 7.40 ± 4.71, P = 0.028). Clinical pregnancy rate and implantation rate were similar between the two groups. In further correlation tests and multivariate linear regression analysis, number of fertilized oocytes and embryo yield were positively correlated to MediDiet adherence of participants.

CONCLUSION

Infertile women with greater adherence to Mediterranean diet pattern were likely to obtain more embryos available in IVF cycle.

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.

Adherence to the Mediterranean diet and IVF success rate among non-obese women attempting fertility

STUDY QUESTION

Is adherence to the Mediterranean diet (MedDiet) associated with better IVF performance in women attempting fertility?

SUMMARY ANSWER

Greater adherence to the MedDiet, defined using the validated Mediterranean diet score (MedDietScore), was associated with a higher likelihood of achieving clinical pregnancy and live birth among non-obese women <35 years of age.

WHAT IS KNOWN ALREADY

Diet impacts fertility and certain nutrients and food groups appear to have a greater effect on reproductive health, but there are relatively few published data on the role of dietary patterns, and the MedDiet in particular, on assisted reproductive performance.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 244 non-obese women (22-41 years of age; BMI < 30 kg/m2) who underwent a first IVF treatment in an Assisted Conception Unit in Athens, Greece, between November 2013 and September 2016. The study was designed to evaluate the influence of habitual dietary intake and lifestyle on fertility outcomes.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Diet was assessed before the IVF treatment via a validated food-frequency questionnaire. Adherence to the MedDiet was assessed through the MedDietScore (range: 0-55), with higher scores indicating greater adherence. Intermediate outcomes (oocyte yield, fertilization rate and embryo quality measures) and clinical endpoints (implantation, clinical pregnancy and live birth) were abstracted from electronic medical records. Associations between MedDietScore and IVF outcomes were analysed using generalized linear models adjusting for age, ovarian stimulation protocol, BMI, physical activity, anxiety levels, infertility diagnosis, caloric intake and supplements use.

MAIN RESULTS AND THE ROLE OF CHANCE

No association of MedDietScore with any of the intermediate outcomes or with implantation was found. However, compared with women in the highest tertile of the MedDietScore (≥36, n = 86), women in the lowest tertile (≤30, n = 79) had significantly lower rates of clinical pregnancy (29.1 vs 50.0%, P = 0.01) and live birth (26.6 vs 48.8%, P = 0.01). The multivariable-adjusted relative risk (95% CI) for clinical pregnancy comparing women in the lowest with women in the highest tertile of the MedDietScore was 0.35 (0.16-0.78; P-trend=0.01), and for live birth it was 0.32 (0.14-0.71; P-trend = 0.01). These associations were significantly modified by women's age (P-interaction <0.01 for both outcomes). MedDietScore was positively related to clinical pregnancy and live birth among women <35 years old (P ≤ 0.01) but not among women ≥35 years. Among women <35 years, a beneficial 5-point increase in the MedDietScore was associated with ~2.7 times higher likelihood of achieving clinical pregnancy and live birth.

LIMITATIONS, REASONS FOR CAUTION

Our finding cannot be generalized to the whole reproductive population nor to obese women nor to women attending infertility clinics around the world. In addition, due to the observational study design, causal inference is limited.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that diet modifications and greater compliance to the Mediterranean diet may help increase the chances of a successful pregnancy and delivering a live baby for women undergoing IVF treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This work was partially supported by a grand from Harokopio University (KE321). All authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

NCT03050944.

Nutrition and Female Fertility: An Interdependent Correlation

Besides aging, a number of non-modifiable lifestyle-related factors, such as smoking, elevated consumption of caffeine and alcohol, stress, agonist sports, chronic exposure to environmental pollutants, and other nutritional habits exert a negative impact on a women's fertility. In particular, metabolic disorders including diabetes, obesity, and hyperlipidemia commonly associated to hypercaloric diets are suspected to affect a woman's fertility either by direct damage to oocyte health and differentiation, or by indirect interference with the pituitary-hypothalamic axis, resulting in dysfunctional oogenesis. Obese women show decreased insulin sensitivity determining persistent hyperinsulinemia, which may be involved in the pathogenesis of Polycystic Ovary Syndrome. Thus, the reduced insulin secretion induced by dietary adjustments is an attractive non-pharmacological treatment to prevent infertility, and a Mediterranean diet aimed at maintaining normal body mass may be effective in the preservation of ovarian health and physiology. Furthermore, in relation to the oxidative stress as a co-factor of defective oocyte maturation, an appropriate intake of proteins, antioxidants and methyl-donor supplements (1-Carbon Cycle) may decrease the bioavailability of toxic oxidants resulting in the protection of oocyte maturation.

Epigenetics

The field of Epigenetics represents the science which helps us understand the influence life has on genetic function. Research has shown that what we do, what we are exposed to, and the internal and external environments have significant influence on the output of our genes. In this article, the reader will understand how alterations in the DNA explain how the genetic output us changed as a result of exposures to life.

Preconception Plasma Phospholipid Fatty Acids and Fecundability

CONTEXT

Fatty acids (FAs) are important for reproductive processes, including steroidogenesis, though associations with fecundability, as measured by time to pregnancy (TTP), are unclear.

OBJECTIVE

To investigate the relationship between preconception plasma phospholipid FA (PPFA) levels and time to human chorionic gonadotropin-pregnancy among women with prior pregnancy loss.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort of 1228 women attempting pregnancy (aged 18 to 40 years, with one or two prior pregnancy losses) followed for up to six cycles at four US university medical centers during 2006 to 2012. PPFA levels were measured at baseline.

MAIN OUTCOME MEASURES

Associations with fecundability overall and by body mass index (BMI) group after adjusting for confounders were estimated using fecundability odds ratios (FORs) and 95% CIs. False discovery rate (FDR) was used to account for multiple comparisons.

RESULTS

Monounsaturated fatty acids (MUFAs) were associated with increased fecundability or shorter TTP [FOR, 1.08 (95% CI, 1.01 to 1.16) per unit increase in percentage of total FAs], whereas polyunsaturated fatty acids (PUFAs) were associated with decreased fecundability or longer TTP [FOR, 0.95 (95% CI, 0.91 to 1.00) per 1% change], though associations only remained significant after FDR adjustment among women with BMI <25 kg/m2. Saturated FA and trans FA were not associated with fecundability. Omega-3 FAs and omega-6 linoleic acid were not associated with fecundability.

CONCLUSION

We observed associations between preconception MUFA and PUFA levels and fecundability among women with normal BMI, highlighting the importance of FA composition among normal-weight women with prior pregnancy loss.

Intake of protein-rich foods in relation to outcomes of infertility treatment with assisted reproductive technologies

Background

Some dietary factors have been linked to outcomes of infertility treatment with assisted reproductive technology (ART), but the role of intake of meats and other protein-rich foods remains unclear.

Objective

The aim of this manuscript was to study the relation between preconception intake of meat and other protein-rich foods and outcomes of infertility treatment with ART.

Design

A total of 351 women enrolled in a prospective cohort at the Massachusetts General Hospital Fertility Center and underwent 598 ART cycles for infertility treatment. Meat intake was assessed with a validated food-frequency questionnaire, and ART outcomes were abstracted from electronic medical records. We estimated the associations between intake of protein-rich foods (meats, eggs, beans, nuts, and soy) and the outcome of live birth per initiated cycle using generalized linear mixed models.

Results

The average total meat intake was 1.2 servings/d, with most coming from poultry (35%), fish (25%), processed meat (22%), and red meat (17%). Fish intake was positively related to the proportion of cycles resulting in live birth. The multivariable-adjusted probabilities of live birth for women in increasing quartiles of fish intake were 34.2% (95% CI: 26.5%, 42.9%), 38.4% (95% CI: 30.3%, 47.3%), 44.7% (95% CI: 36.3%, 53.4%), and 47.7% (95% CI: 38.3%, 57.3%), respectively (P-trend = 0.04). In the estimated substitution analyses, the ORs of live birth associated with increasing fish intake by 2 servings/wk were 1.54 (95% CI: 1.14, 2.07) when fish replaced any other meat, 1.50 (95% CI: 1.13, 1.98) when fish replaced any other protein-rich food, and 1.64 (95% CI: 1.14, 2.35) when fish replaced processed meat.

Conclusions

Fish consumption is related to a higher probability of live birth following infertility treatment with ART. This trial was registered at clinicaltrials.gov as NCT00011713.

The impact of maternal lifestyle factors on periconception outcomes: a systematic review of observational studies

The main risk factors for important reproductive health issues such as subfertility and perinatal mortality largely originate in the periconception period. To evaluate associations between modifiable maternal lifestyle factors and periconception outcomes, a systematic search was conducted for relevant studies published from 1990 to February 2017 on Embase, Medline, Web of Science, Cochrane database, PubMed and Google Scholar. The initial search identified 6166 articles, of which 49 studies were eligible for inclusion. Fecundity (the capacity to have a live birth) showed significant inverse associations with smoking, alcohol use and poor diet. Studies regarding time to pregnancy showed a decline in fecundity ratios (the monthly conception rate among exposed relative to unexposed couples) with increasing body mass index (BMI). Furthermore, risk of first-trimester miscarriage was found to be increased in smokers, alcohol and caffeine consumers, and with increasing BMI. Vitamin supplement use showed a decrease in this risk. This review demonstrates that maternal modifiable lifestyle factors affect periconception outcomes. If couples planning a pregnancy are more aware and supported to adopt healthy lifestyles during the periconceptional 'window of opportunity', short-term reproductive health as well as health in later life and even of future generations can be further improved.

Dietary Patterns and The Outcomes of Assisted Reproductive Techniques in Women with Primary Infertility: A Prospective Cohort Study

Background

Infertility is one of the most common challenges that women in reproductive age would encounter today. The maternal nutritional status could be a determinant of oocyte quality and embryonic growth. This study was conducted to assess the relationship between dietary patterns and reproductive outcomes in infertile women.

Materials and Methods

This prospective cohort study was conducted on 140 women with primary infertility who had referred to Isfahan Fertility and Infertility center, Isfahan, Iran. The average number of total oocytes and metaphase II oocytes, the fertilization rate, the ratio of good and bad quality embryo and biochemical and clinical pregnancy were considered as the outcomes of assisted reproductive techniques (ART). A 168-item food frequency questionnaire was used for estimating the dietary intakes during the last year. Factor analysis was used for identifying the dietary patterns and analysis of variance (ANOVA), analysis of covariance (ANCOVA), chi-square, and logistic regression analysis were used for assessing the relation between dietary patterns and ART’s outcomes.

Results

Three major dietary patterns (the healthy, western and unhealthy diet) were identified. Women with high adherence to the “healthy diet” had a higher educational level and were employed. There was a significant increase in the average number of total oocytes (P-trend=0.009) and metaphase II oocytes (P-trend=0.006) in the third tertile of “healthy diet” compared to the first tertile. Also, women with high adherence to the second tertile of “unhealthy” diet compared to the first tertile, had a significantly lower chance of getting pregnant [odds ratio (OR): 0.14, 95% confidence interval (CI): 0.3-0.7].

Conclusion

Nutrition status could affect infertility treatment outcomes. Greater adherence to the healthy diet may enhance oocyte quality and quantity. Unhealthy diet could adversely affect the chance of getting pregnant.

The Influence of Diet on Fertility and the Implications for Public Health Nutrition in the United States

Despite growing evidence of the impact of diet on human fertility, few studies have examined the public health implications of this association in the United States (U.S.). This narrative review summarizes current scientific evidence on associations between dietary intake and fertility, discusses challenges in the public health landscape surrounding infertility, and proposes evidence-based recommendations to address these issues. Diets high in unsaturated fats, whole grains, vegetables, and fish have been associated with improved fertility in both women and men. While current evidence on the role of dairy, alcohol, and caffeine is inconsistent, saturated fats, and sugar have been associated with poorer fertility outcomes in women and men. Furthermore, women and men with obesity [body mass index (BMI) ≥ 30 kg/m²] have a higher risk of infertility. This risk is extended to women who are underweight (BMI <20 kg/m²). Diet and BMI influence outcomes during clinical treatment for infertility. Further, women in the U.S. who belong to an underrepresented minority group, have low income, or have low educational attainment, have significantly higher rates of infertility outcomes as compared to women who are non-Hispanic white, have high income, or have high educational attainment. Given this, it may be prudent to integrate nutrition counseling into both clinical guidelines for infertility as well as national dietary guidelines for individuals of reproductive age. Further studies on diet and reproductive health may enhance our ability to improve existing fertility programs across the U.S. and to deliver tailored care to women and men within at-risk groups.

Diet and fertility: a review

The literature on the relationship between diet and human fertility has greatly expanded over the last decade, resulting in the identification of a few clear patterns. Intake of supplemental folic acid, particularly at doses higher than those recommended for the prevention of neural tube defects, has been consistently related to lower frequency of infertility, lower risk of pregnancy loss, and greater success in infertility treatment. On the other hand and despite promising evidence from animal models, vitamin D does not appear to exert an important role in human fertility in the absence of deficiency. Antioxidant supplementation does not appear to offer any benefits to women undergoing infertility treatment, but it appears to be beneficial when it is the male partner who is supplemented. However, the available evidence does not allow discerning which specific antioxidants, or at which doses, are responsible for this benefit. Long-chain omega-3 fatty acids appear to improve female fertility, although it remains unclear to what extent contamination of shared food sources, such as fish with high levels of environmental toxicants, can dampen this benefit. Lastly, adherence to healthy diets favoring seafood, poultry, whole grains, fruits, and vegetables are related to better fertility in women and better semen quality in men. The cumulative evidence has also piled against popular hypotheses. Dairy and soy, once proposed as reproductive toxicants, have not been consistently related to poor fertility. In fact, soy and soy supplements appear to exert a beneficial effect among women undergoing infertility treatment. Similarly, because data from large, high-quality studies continue to accumulate, the evidence of a potentially deleterious effect of moderate alcohol and caffeine intake on the ability to become pregnant seems less solid than it once did. While a complete picture of the role of nutrition on fertility is far from complete, much progress has been made. The most salient gaps in the current evidence include jointly considering female and male diets and testing the most consistent findings in randomized trials.

Mediterranean Diet and Health Outcomes in the SUN Cohort

The Mediterranean Dietary (MedDiet) Pattern has been linked to many beneficial health effects. This review summarizes the main findings of a prospective cohort study, the Seguimiento Universidad de Navarra (SUN) cohort, specifically focused on MedDiet and the risk of major chronic disease. It is an open cohort in which 22,786 Spanish university graduates have participated since 1999 until February 2018. Data on diet, lifestyle and clinical diagnosis are collected at baseline and every two years. After reviewing 21 publications from the SUN cohort on the effects of the MedDiet, we conclude that this cohort has provided good evidence that a high MedDiet adherence is associated with a reduced incidence of all-cause mortality, fatal and non-fatal major cardiovascular disease (CVD), type 2 diabetes, weight gain, metabolic syndrome, depression, cognitive decline, and nephrolithiasis. An inverse dose-response relationship was found for many of these associations. The MedDiet was also associated with lower average heart rate, a mitigation of the harmful effects of overweight/obesity on the risk of CVD, and an attenuation of the effects of obesity on type 2 diabetes. A suggestion that the MedDiet may enhance fertility was also found.

Obstetric and perinatal outcomes in subfertile patients who conceived following low technology interventions for fertility enhancement: a comprehensive review

PURPOSE

Low technology interventions for fertility enhancement (LTIFE) are strategies that avoid retrieval, handling, and manipulation of female gametes. The definition of LTIFE is yet to be widely accepted and clarified, but they are commonly used in milder cases of infertility and subfertility. Based on these considerations, the aim of the present study was comprehensively to review and investigate the obstetric and perinatal outcomes in subfertile patients who underwent LTIFE.

METHODS

A literature search up to May 2017 was performed in IBSS, SocINDEX, Institute for Scientific Information, PubMed, Web of Science, and Google Scholar. An evidence-based hierarchy was used according to The Oxford Centre for Evidence-Based Medicine to determine which articles to include and analyze, and to provide a level of evidence of each association between intervention and outcome.

RESULTS

This analysis identified preliminary and low-grade evidence on the influence of LTIFE on obstetric and perinatal outcomes in subfertile women.

CONCLUSIONS

LTIFE women should deserve major consideration from Clinicians/Researchers of Reproductive Medicine, because these treatments could be potentially responsible for mothers' and babies' complications. So far, the lack of well-designed and unbiased studies makes further conclusions difficult to be drawn.