According to the review, the classic model centered on prostaglandins incompletely accounts for two well-known phenomena: the fact that some patients do not respond to non-steroidal anti-inflammatory drugs, a multifactorial and mechanistically nonspecific form of non-response, and the finding that pain thresholds remain lowered even outside menstruation. NEIF therefore organizes primary dysmenorrhea into six interacting layers: progesterone withdrawal with prostaglandin dysregulation; cytokine amplification through NF-κB signaling; oxidative stress; peripheral sensitization; central neuroplasticity; and genetic and epigenetic susceptibility. The authors emphasize that the strength of evidence varies considerably across these layers, ranging from direct human data and replicated genetic findings to correlative, neuroimaging-based or preclinical support.

One extension discussed in the review is explicitly flagged as speculative. The proposal that the NLRP3 inflammasome and pyroptosis, a form of inflammatory cell death, contribute to primary dysmenorrhea is not treated as a core NEIF level or a candidate endotype, because direct human evidence in the condition is currently absent. The authors describe this as an evidence-gated validation gap rather than an established mechanism, noting that direct human validation of the NLRP3 link would be desirable but is not required for the core framework to stand.

NEIF also identifies emerging candidate biomarkers, including oxylipins measured in menstrual effluent, circulating nerve growth factor and brain-derived neurotrophic factor, neuroimaging intermediate phenotypes, and genetic variants. None of these markers has yet been clinically qualified, meaning none is ready for diagnostic or treatment-guiding use. The framework further generates three candidate mechanistic endotypes, labeled prostaglandin-predominant, inflammatory–oxidative and neurogenic–central. The authors are careful to specify that these endotypes are intended for research only and do not constitute a clinical classification of patients.

By situating menstrual pain within a neuroendocrine and inflammatory network that extends from the uterus to the brain, the review aims to reframe primary dysmenorrhea as a systemic condition and to provide concrete, testable hypotheses for future studies. If validated, the layered model could help explain why pain sensitivity persists between cycles and why anti-inflammatory treatment fails in some patients, while the proposed biomarkers and research-only endotypes offer a structured path toward mechanism-based investigation of a condition the authors describe as understudied and inadequately managed despite its high prevalence.

Subject of Research: A review proposing the neuroendocrine–inflammatory framework (NEIF), a multi-layered hypothesis for primary dysmenorrhea pathogenesis and candidate biomarkers

Article Title: From uterus to brain: the NEIF hypothesis—a multi-layered framework for primary dysmenorrhea pathogenesis and emerging biomarkers

Article References: Wu, D., Chen, X., Zhu, X., & Zhang, M. (2026). From uterus to brain: the NEIF hypothesis—a multi-layered framework for primary dysmenorrhea pathogenesis and emerging biomarkers. Molecular Biology Reports, 53(1), Article 1806. https://doi.org/10.1007/s11033-026-13009-w

Image Credits: AI Generated

DOI: 10.1007/s11033-026-13009-w

Keywords: primary dysmenorrhea, NEIF hypothesis, prostaglandins, NF-kB, NLRP3 inflammasome, biomarkers, neuroimaging, endotypes, Molecular Biology Reports, uterus, brain, NEIF