Lack of a meaningful association between dietary patterns and in vitro fertilization outcome among Japanese women

Association of ambient PM2.5 and its components with in vitro fertilization outcomes: The modifying role of maternal dietary patterns

Despite the associations of dietary patterns and air pollution with human reproductive health have been demonstrated, the interaction of maternal preconception diet and PM2.5 and its components exposure on in vitro fertilization (IVF) treatment outcomes has not been investigated. A total of 2688 couples from an ongoing prospective cohort were included. Principle component analysis with varimax rotation was performed to determine dietary patterns. One-year and 85-day average PM2.5 and its components exposure levels before oocyte retrieval were estimated. Generalized linear regression models were conducted to assess the association of dietary patterns and PM2.5 and its components exposure with IVF outcomes. Interactive effects of dietary patterns on the association between PM2.5 and its components and IVF outcomes were evaluated by stratified analyses based on different dietary patterns. A positive association between the "Fruits-Vegetables-Dairy" pattern and normal fertilization (p-trend = 0.009), Day 3 available embryos (p-trend = 0.048), and top-quality embryos (p-trend = 0.041) was detected. Conversely, women with higher adherence to the "Puffed food-Bakery-Candy" pattern were less likely to achieve Day 3 available embryos (p-trend = 0.042) and top-quality embryos (p-trend = 0.030), clinical pregnancy (p-trend = 0.049), and live birth (p-trend = 0.020). Additionally, increased intake of animal organs and seafood improved the odds of live birth (p-trend = 0.048). Exposure to PM2.5, SO42-, organic matter (OM), and black carbon (BC) had adverse effects on embryo development and pregnancy outcomes. Furthermore, our findings indicated that the effects of PM2.5 components exposure on normal fertilization and embryo quality were modified by the "Grains-Tubers-Legumes". Moreover, moderate intake of animal organs and seafood appeared to attenuate the effect of NO3- and NH4+ on the risk of early abortion. Our findings provide human evidence of the interaction between dietary patterns and PM2.5 exposure on IVF outcomes during preconception, implicating the potential for dietary interventions in infertile women to improve reproductive outcomes under conditions of unavoidable ambient air-pollutant exposure.

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.

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.

Mediterranean diet and infertility: a systematic review with meta-analysis of cohort studies

Context

The Mediterranean diet (MD) is a dietary pattern with evidence of positive health impact, and some nutrients in this diet have already been researched for their effectiveness in fertility. However, there are still questions about whether high adherence to the MD could be a factor that contributes to positive fertility outcomes in infertile men and women.

Objective

A systematic review and meta-analysis were conducted to determine whether a greater adherence to the MD can improve fertility markers and outcomes in infertile men and women.

Data sources

The MEDLINE, BVS, SciELO, CENTRAL, and Embase databases and gray literature were searched from their inception to May 2022.

Study selection

Data were included from cohort studies that addressed MD and outcomes.

Data extraction

Data searches, article selection, data extraction, and risk-of-bias assessments were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

A total of 11 studies met the inclusion criteria (n = 13 157 women and 1338 men). Greater adherence to the MD was associated with live births (I2 = 83.16%; odds ratio [OR], 0.652; 95%CI, 0.408–3.194), pregnancy rate (I2 = 93.83%; OR, 1.192; 95%CI, 0.349–4.325), sperm concentration >15 × 106/mL (I2 = 32.97%; OR 2.862; 95%CI, 1.583–5.174), and sperm count > 39 × 106/mL (I2 = 48.1%; OR, 2.543; 95%CI, 1.319–4.904); however, in an inconsistent scenario regarding the meta-analysis.

Conclusion

Current evidence of high adherence to MD and fertility markers is insufficient to support their clinical application, even though it indicates sperm improvement and a possibility of better pregnancy outcomes.

Systematic Review Registration

PROSPERO registration no. 169396.

The Effect of Dietary Patterns on Clinical Pregnancy and Live Birth Outcomes in Men and Women Receiving Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

The nutritional status of reproductive-aged couples can have a significant impact on fertility status, but the effect of dietary patterns on pregnancy outcomes in people using assisted reproductive technologies (ARTs) is currently unknown. This review aimed to synthesize the published research investigating the relation between preconception dietary patterns and clinical pregnancy or live birth in men and women of reproductive age undergoing ART. Six electronic databases were systematically searched for original research published between January 1978 and June 2021. Original research reporting on the effect of predefined dietary patterns on either clinical pregnancy and/or live birth rates following in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in men and women aged 18-49 y was eligible for inclusion. Studies were assessed for risk of bias according to the Cochrane guidelines. Included studies underwent qualitative and quantitative synthesis using random-effects model meta-analyses. Thirteen studies (12 cohort studies, 1 randomized controlled trial) reporting on 3638 participants (93% female) were included in the review. All studies had a moderate-high risk of bias. In individual studies, maternal adherence to 4 dietary patterns [Mediterranean diet (RR: 1.22; 95% CI: 1.05, 1.43), novel profertility diet (OR: 1.43; 95% CI: 1.19, 1.72), Iranian traditional medicine diet (OR: 3.9; 95% CI: 1.2, 12.8), Dutch national dietary recommendations diet (OR: 1.65; 95% CI: 1.08, 2.52)] was associated with increased likelihood of achieving a clinical pregnancy, while 2 dietary patterns [novel profertility diet (OR: 1.53; 95% CI: 1.26, 1.85), Mediterranean diet (RR: 1.25; 95% CI: 1.07, 1.45)] were associated with increased probability of live birth. Meta-analyses showed an association between adherence to the Mediterranean dietary pattern and live birth across 2 studies (OR: 1.98; 95% CI: 1.17, 3.35; I2 = 29%, n = 355), but no association with clinical pregnancy. As the relation between dietary patterns and ART outcomes is currently inconsistent, higher-quality nutrition research is required to further explore this emerging field of interest (PROSPERO registration: CRD42020188194).

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.

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).

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.

The association between previous induced abortion and in vitro fertilization outcomes: A retrospective cohort study in Hefei, China

OBJECTIVES

To assess the association between previous induced abortion and in vitro fertilization (IVF) outcomes among Chinese women.

STUDY DESIGN

In this retrospective cohort study, a total of 1436 infertility patients treated with IVF for the first time in the reproductive centre of Anhui Province Maternity and Child Health Hospital from February 2014 to April 2018 were selected as the study population, and 95 (6.6 %) had a history of induced abortion. Data were assessed from the hospital electronic database and medical records in the reproductive centre.

RESULTS

In total, 818 women (57.0 %) achieved clinical pregnancy, and 501 (34.9 %) achieved live birth. After adjustments for a series of potential confounding factors, women with a history of induced abortion had a significantly decreased probability of clinical pregnancy per transfer (OR: 0.71, 95 % CI: 0.53, 0.95, p = 0.037) and live birth per pregnancy (OR: 0.52, 95 % CI: 0.30, 0.90, p = 0.021) and a higher risk of miscarriage per pregnancy (OR: 1.89, 95 % CI: 1.24, 2.88, p = 0.009) than those without. Because relevant information was unavailable, the impacts of different types of previous induced abortion were not assessed.

CONCLUSIONS

Previous induced abortion may have an adverse effect on IVF outcomes among infertility patients.

Adherence to healthy dietary patterns and outcomes of assisted reproduction: a systematic review and meta-analysis

This systematic review and meta-analysis aimed to evaluate the association between adherence to a healthy dietary pattern and outcomes of assisted reproductive techniques (ARTs). PubMed, Embase and Web of Science were searched for eligible studies through December 2019 according to the population, intervention, comparison, outcome and study design (PICOS) criteria. Eight prospective cohort studies (S) reporting pregnancy outcomes (O) of higher vs lower adherence to a healthy dietary pattern (I/C) in women undergoing ART treatment (P) were included, involving a total of 2229 women with 2067 embryo transfer cycles. The pooled odds ratio (OR) for positive pregnancy test, clinical pregnancy and ongoing pregnancy/live birth was 0.82 (95% confidence interval [CI] 0.65-1.03), 0.99 (95% CI 0.68-1.44) and 1.30 (95% CI 0.81-2.09), respectively. In conclusion, greater adherence to a healthy dietary pattern rich in vegetables, fruits, whole grains, legumes and fish, may not be significantly related to ART success.