Placenta and Reproductive Medicine

Polycyclic aromatic hydrocarbons exposure in humans and reproductive health outcomes: An umbrella review

2026-08-21T09:41:19+08:00

Background: Polycyclic aromatic hydrocarbons (PAHs) are a public health threat, but evidence linking PAHs exposure to adverse reproductive health outcomes remains unclear. Methods: PubMed, Embase, and Web of Science were searched from inception to April 17, 2024, for systematic reviews and meta-analyses of observational studies on PAHs exposure and reproductive outcomes. Methodological quality was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR). Random-effects models generated pooled estimates, without conversion among beta coefficients (β), odds ratios (OR), and risk ratios (RR). Evidence credibility was evaluated using evidence-class criteria and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Results: Five articles reporting 15 associations were included. Four (26.7%) were significant: bladder cancer in aluminum production workers (RR = 1.26, 95% CI= 1.16, 1.36) and iron and steel foundry workers (RR = 1.36, 95% CI= 1.14, 1.62), birth weight reduction associated with PAHs DNA-adducts (OR = 1.02, 95% CI = 1.01, 1.03), and offspring attention deficit hyperactivity disorder (ADHD) associated with prenatal PAHs exposure (RR = 1.73, 95% CI = 1.15, 2.58). Dietary PAHs were not associated with birth length (β = -0.04, 95% CI = -0.09, 0.01) or birth weight (β = -5.65, 95% CI = -16.35, 5.06). Overall, the certainty of evidence was generally low or very low. Conclusion: Occupational and prenatal PAHs exposures may be associated with adverse outcomes, but evidence was low or very low certainty, and most birth-size outcomes showed no significant pooled associations.

Reproducibility and relative validity of a food frequency questionnaire developed among reproductive-aged women in Northeast China

2026-08-24T09:35:25+08:00

Background: To evaluate the reproducibility and relative validity of a newly developed 118-item food frequency questionnaire (FFQ) for assessing habitual dietary intake among reproductive-aged women in Northeast China. Methods: A total of 207 eligible reproductive-aged women were enrolled. After exclusions for incomplete records or implausible energy intakes, 192 completed two FFQs (FFQ1 [first FFQ administration] and FFQ2 [second FFQ administration]) 9 months apart, 182 completed the FFQ and four planned 4-day weighed diet records (WDRs). Reproducibility was assessed using crude and energy-adjusted Spearman correlation coefficients (SCC), intraclass correlation coefficients (ICC), weighted kappa (κ_w), and quartile misclassification. Relative validity was assessed against WDRs using crude, energy-adjusted, and de-attenuated SCC, κ_w, and quartile misclassification. Results: For reproducibility, energy-adjusted SCC ranged from 0.32-0.60 (median 0.48) for food groups and 0.30-0.58 (median 0.44) for nutrients; κ_w ranged from 0.24-0.56 (median 0.43) and 0.26-0.53 (median 0.37), respectively. For validity, de-attenuated SCC ranged from 0.32-0.75 (median 0.57) for food groups and 0.29-0.58 (median 0.48) for nutrients. Same-or-adjacent quartile classification ranged from 76.15%-92.25% (median 85.72%) for reproducibility and 66.94%-85.48% (median 78.23%) for validity, with low extreme misclassification (median < 5% for both). Conclusions: The FFQ demonstrated acceptable reproducibility and relative validity for ranking the habitual intake of most foods and nutrients among reproductive-aged women in Northeast China, supporting its use in epidemiological studies of diet and reproductive health.

Appraising the causal role of physical activity and sedentary behavior in female reproductive health: A Mendelian randomization study

2026-09-04T10:49:47+08:00

Background: Physical inactivity and sedentary behavior have been associated with adverse female reproductive outcomes, but whether these associations are causal remains uncertain. Methods: We used genome-wide association study summary data to evaluate four self-reported activity-related traits—leisure screen time (LST), moderate-to-vigorous physical activity (MVPA), sedentary behavior at work (SDW), and sedentary commuting behavior (SDC)—in relation to 25 female reproductive conditions. Linkage disequilibrium score regression was used to assess genetic correlations. Univariable and multivariable Mendelian randomization (MR) analyses were performed, with MR-Egger, weighted median, weighted mode, MR-RAPS, and Causal Analysis Using Summary Effect Estimates (CAUSE) used for sensitivity analyses. Results: Longer LST was causally associated with higher odds of adenomyosis, endometriosis, excessive, frequent, and irregular menstruation, ectopic pregnancy, and abortion. MVPA was causally associated with lower odds of adenomyosis, endometriosis, and excessive, frequent, and irregular menstruation. Multivariable MR further supported independent associations of LST with abortion and postpartum depression. SDW showed limited associations, whereas no significant causal association was identified for SDC. Conclusions: Genetic evidence supports causal associations of physical activity and sedentary behavior with several female reproductive outcomes. Reducing leisure screen time and increasing moderate-to-vigorous physical activity may represent modifiable strategies to support female reproductive health.

Interpretation of the 2026 clinical practice guideline on polycystic ovary syndrome and the gut microbiota: From evidence to clinical translation

2026-09-23T09:15:27+08:00

Polycystic ovary syndrome (PCOS) is a heterogeneous reproductive, endocrine, and metabolic disorder, and the gut microbiota has emerged as an important focus of mechanistic and translational research. The 2026 clinical practice guideline on PCOS and the gut microbiota was developed to bridge the gap between rapidly evolving microbiome research and uncertainty regarding its clinical application. It addresses nine core questions and provides 15 recommendations covering disease association, microbiome testing, probiotics and prebiotics, dietary interventions, fecal microbiota transplantation, interactions with pharmacologic therapy, metabolic surgery, and the gut-brain axis. This article provides a focused interpretation of these recommendations, emphasizing the clinical implications of recommendation strength, the distinction between research-oriented microbiome analyses and routine diagnostic testing, the adjunctive role of microbiota-targeted interventions, and the need to distinguish mechanistic plausibility from demonstrated clinical benefit. Implementation should remain embedded within established PCOS management, with lifestyle modification, evidence-based pharmacotherapy, reproductive care, and mental health support as the foundation. Microbiota-targeted strategies should be individualized according to evidence maturity, strain or product specificity, patient phenotype, safety, and feasibility. Future priorities include standardized microbiome methodologies, multicenter prospective studies, adequately powered randomized trials, clinically meaningful reproductive outcomes, and long-term safety assessment. This interpretation aims to support appropriate clinical application while avoiding premature translation of preliminary microbiome findings into routine practice.

Beyond microbial composition: Toward mechanism-based postbiotics for endometrial aging

2026-08-27T11:26:01+08:00