Objectives: High levels of follicle stimulating hormone (FSH) in infertile males received a significant attention and exploration. Studies investigating the isolated deficiency of FSH in males are few, and its real prevalence is still unknown. Therefore, the objectives of the current study was to report the prevalence of isolated low FSH in infertile males and highlight their demographics and standard sperm parameters. Methods: Records of 3335 infertile men were retrospectively checked. Patients with isolated low FSH were retrieved. FSH levels were categorized into 3 groups based on the number of affected sperm parameter (s). Study variables were also arranged into 2 groups in relation to smoking history. A control group was included to document the changes in sperm morphology. Results: Isolated low FSH (1.146 ± 0.219 mIU/mL) was found in 29 (0.87%) patients. All patients showed at least one abnormal sperm parameter. The abnormal parameters were present in different combinations within the same patient but with no significant correlations with the FSH levels. The FSH levels got lower as the number of the affected sperm parameters increased although the decline was insignificant. The most frequent abnormal parameter presented was sperm morphology (86.2%). Anomalous sperm morphology was highly and significantly demonstrated in the head; specifically in acrosome. Abnormal sperm parameters were present in both smoking and nonsmoking groups but with no significant differences in between. Conclusions: Isolated low FSH among infertile males has a low prevalence. This may be associated with abnormality in semen parameters; particularly sperm morphology. These patients are suggested to be found as a primary entity. However, an additional work-up is highly recommended to validate this hypothesis.
Male infertility; Low FSH; Sperm parameters