Inflammation can contribute to infertility in two ways. On its own, inflammation can damage cells and tissues in the reproductive organs, such as eggs, ovaries, or sperm. Chronic inflammation can also be connected to an autoimmune response, in which the body attacks its own tissue via antibodies. People with autoimmune conditions are more susceptible to these complications, and it is even more important for them to work on decreasing inflammation in every way possible.
Unexplained infertility is defined as the inability to conceive after 12 months of unprotected intercourse in couples where known causes of infertility have been ruled out. It is thus considered a diagnosis of exclusion. Its pathophysiology remains unclear, although the literature suggests a possible contribution by increased levels of oxidative stress. Inflammation and oxidative stress are closely related and tightly linked pathophysiological processes. As the inflammatory process can induce oxidative stress, the oxidative stress can also induce inflammation through activation of multiple pathways.
Infection is also a major factor in male subfertility, second only to abnormal semen parameters. Epididymal or ductal obstruction, testicular damage from orchitis, development of anti-sperm antibodies, etc are all possible mechanisms by which infection can affect male fertility.
In males, the role of oxidative stress (imbalance between production and accumulation of oxygen reactive species (ROS)) in pathologies has long been recognized as a significant contributor to infertility. The key predictors of fertilization capability are sperm count and motility. These essential factors can be disturbed by ROS and much importance has been given to oxidative stress as a major contributor to infertility in males.
Chronic inflammation of the cervix and endometrium, alterations in reproductive tract secretions, induction of immune mediators that interfere with gamete or embryo physiology, and structural disorders such as intrauterine synechiae all contribute to female infertility.
Inflammation leads to anatomic disorders primarily as a result of infectious disease; including polycystic ovary syndrome (PCOS), endometriosis (inflammation of inner lining of the uterus), recurrent miscarriage, and premenstrual syndrome (PMS).
The contribution of oxidative stress to male infertility has been well documented and extensively studied. On the other hand, the role of oxidative stress in female infertility continues to emerge as a topic of interest, and thus, the majority of conducted studies provide indirect and inconclusive evidence regarding the oxidative effects on female reproduction.