Purpose: Pituitary neuroendocrine tumor (PitNET), excluding prolactinoma, often requires endoscopic endonasal surgery (EES). Identifying predictive factors for complications, and particularly rare ones such as hypogonadotropic hypogonadism (HH) that may affect fertility, is challenging. This study investigated de-novo postoperative HH and its potential impact on fertility.

Methods: We conducted a retrospective study of 211 patients undergoing EES. HH was evaluated using age- and gender-specific criteria. The characteristics of patients of reproductive age were analyzed to identify risk factors for de-novo postoperative HH.

Results: Twelve of the 60 patients of reproductive age with no preoperative HH (20%) developed de-novo HH within 4–6 months’ follow-up, with 7 (12%) presenting long-term HH (median: 893 days). De-novo HH was significantly associated with corticotroph adenoma (p=0.01). Median tumor size was greater in HH than non-HH patients (p < 0.01).

Conclusion: De-novo HH is a frequent complication of pituitary surgery, affecting 1 in 5 patients in our cohort, and is persistent in most cases. While risk factors such as large tumor size and corticotroph subtype were identified, the condition is still difficult to predict. These findings underscore the importance of integrating this risk into preoperative counseling and follow-up.