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

Intra-patient analysis of individual weight gain or loss between IVF cycles: cycle now and transfer later

STUDY QUESTION

What is the impact of clinically significant weight change on outcomes related to IVF cycle performance?

SUMMARY ANSWER

While individual weight loss did not significantly impact ovarian response to stimulation or other cycle outcome parameters in our study, some positive associations were found for individual weight gain.

WHAT IS KNOWN ALREADY

The role of weight-change in patients undergoing IVF has been largely studied by comparing weight loss in different cohorts of patients stratified by a static BMI. Specifically, obesity has been extensively studied in relation to its negative effects on assisted or unassisted conception outcomes and ovulatory function. Previous research has shown conflicting results, while BMI, which is commonly used as a marker of obesity, may not accurately reflect the underlying factors affecting fertility in obese patients.

STUDY DESIGN, SIZE, DURATION

This study utilized a retrospective within-patient repeated measurement analysis design to assess the impact of weight change on IVF outcomes in cycles where all embryos were cryopreserved at the blastocyst stage for transfer at a later date.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at an academically affiliated fertility center. The data included 961 women who underwent at least two IVF cycles between December 2014 and June 2020, with documented short-term weight gain (n = 607) or weight loss (n = 354) within 1 year from their initial IVF cycle. Multivariable generalized estimating equations (GEE) and generalized linear mixed models (GLMM) were employed to assess associations between weight change and outcomes across cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

The multivariable models indicated that weight loss did not show any significant associations with the numbers of oocytes retrieved, or mature oocytes, the fertilization rate or the blastulation rate. However, weight gain demonstrated a minor positive association with the number of oocytes retrieved in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.01) and GLMM models (0.01, 95% CI: 0.01-0.00). There was also a potential increase in the fertilization rate with weight gain, as indicated by a positive coefficient in both GEE models (coefficient: 0.01, 95% CI: 0.00-0.02) and GLMM models (coefficient: 0.01, 95% CI: 0.00-0.01). However, the association between weight gain and the embryo blastulation rate was not statistically significant in any model.

LIMITATIONS, REASONS FOR CAUTION

This study focused on cycle performance parameters instead of reproductive outcomes, which restricted our ability to evaluate the impact of weight change on cumulative live birth rates. Additionally, the study did not account for variables such as stimulation protocols, potentially introducing confounding factors and limiting the generalizability of the results.

WIDER IMPLICATIONS OF THE FINDINGS

Although obesity is associated with adverse obstetrical risks, there is less evidence of adverse reproductive outcomes in IVF cycles. We therefore recommend that an IVF cycle should not be delayed due to weight, so that the patient is not adversely affected by increasing age. The IVF cycle should aim to freeze all embryos, so that embryo transfer can then occur after weight loss, so as to limit the recognized obstetrical risks.

STUDY FUNDING/COMPETING INTEREST(S)

The study was not funded and there were no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Nut Consumption and Fertility: a Systematic Review and Meta-Analysis

The high concentration of omega-3 polyunsaturated fats, dietary fibers, vitamins, minerals, and polyphenols found in nuts suggest their regular consumption may be a simple strategy for improving reproductive health. This systematic review and meta-analysis aimed to present up-to-date evidence regarding the association between nut intake and fertility outcomes in males and females. Ovid MEDLINE, Embase, CINAHL, and Scopus were searched from inception to 30 June 2023. Eligible articles were interventional or observational studies in human subjects of reproductive age (18-49 y) that assessed the effects (or association) of dietary nut consumption (for a minimum of 3 mo) on fertility-related outcomes. Random-effects meta-analyses were completed to produce a pooled effect estimate of nut consumption on sperm total motility, vitality, morphology, and concentration in healthy males. Four studies involving 875 participants (646 males, 229 females) were included in this review. Meta-analysis of 2 RCTs involving 223 healthy males indicated consumption of ≥ 60g nuts/d increased sperm motility, vitality, and morphology in comparison to controls but had no effect on sperm concentration. Nonrandomized studies reported no association between dietary nut intake and conventional sperm parameters in males, embryo implantation, clinical pregnancy or live birth in males and females undergoing ART. Our meta-analysis shows that including at least 2 servings of nuts daily as part of a Western-style diet in healthy males improves sperm parameters, which are predictors of male fertility. Due to their nutritional profile, nuts were found to have potential to promote successful reproductive outcomes. This trial was registered at PROSPERO (CRD42020204586).

The association between Diet Quality Index-International score and risk of diminished ovarian reserve: a case-control study

Introduction

Although limited evidence exists on the beneficial reproductive effects of diet quality indices, the association is still largely unknown. We aimed to investigate the association between Diet Quality Index-International (DQI-I) and antral follicle count (AFC) and serum antimullerian hormone (AMH) as precise and sensitive markers of ovarian reserve and to assess the risk of diminished ovarian reserve (DOR) in women seeking fertility treatments.

Methods

In a case-control study, 370 women (120 women with DOR and 250 women with normal ovarian reserve as controls), matched by age and body mass index (BMI), were recruited. Dietary intake was obtained using a validated 80-item semi-quantitative food frequency questionnaire (FFQ). The quality of diets was assessed using DQI-I, which included four major dietary components: variety (0-20 points), adequacy (0-40 points), moderation (0-30 points), and overall balance (0-10 points). DQI-I score was categorized by quartiles based on the distribution of controls. AFC, serum AMH and anthropometric indices were measured. Logistic regression models were used to estimate multivariable odds ratio (OR) of DOR across quartiles of DQI-I score.

Results

Increased adherence to DQI-I was associated with higher AFC in women with DOR. After adjusting for potential confounders, the odds of DOR decreased with increasing DQI-I score (0.39; 95% CI: 0.18-0.86).

Conclusion

Greater adherence to DQI-I, as a food and nutrient-based quality index, may decrease the risk of DOR and improve the ovarian reserve in women already diagnosed with DOR. Our findings, though, need to be verified through prospective studies and clinical trials.

Female obesity and infertility: outcomes and regulatory guidance

Obesity has been associated with reduced fertility, although the dynamics and mechanisms which link excess weight to reduced fertility are not yet fully clarified. Obese women, especially those with central obesity, are less likely to conceive per cycle. Obese women suffer from perturbations of the hypothalamus-pituitary-ovary axis, disturbances of the menstrual cycle and are up to three times more likely to suffer from oligo/anovulation. A delicate hormonal balance regulates follicular development and the maturation of oocytes and it has been observed that obesity can alter the hormonal environment: adipocytes, in fact, are responsible for the production of a hormone called leptin (present in high quantities in obese women) which has been associated with reduced fecundity. In addition to compromising ovulation, obesity negatively affects the development and implantation of the endometrium. The expression of polycystic ovary syndrome (PCOS) is regulated, in part, by weight, so obese women with PCOS often have a more severe phenotype and higher subfertility rates. Furthermore, obesity impairs women's response to medically assisted procreation (MAP) treatments. The authors have set out to delineate a broad-ranging overview of obesity's impact on female fertility, by drawing upon sources spanning the 1994-2022 period. Assisted reproductive technology (ART) procedures are also discussed as they relate to obese patients. In addition the dynamics by which maternal obesity reportedly affects fetal, neonatal and child development have also been briefly enunciated.