Introduction: Obesity is a public health problem with high prevalence and constitutes a modifiable risk factor associated with the development of premalignant and malignant endometrial pathology, including both atypical endometrial hyperplasia and endometrial carcinoma. 
General objective: To analyze the relationship between body mass index (BMI) and premalignant and malignant endometrial pathology. 
Specific objectives: To calculate the prevalence of endometrial pathology in patients with and without obesity, and to compare BMI between patients with and without endometrial pathology.
Materials and methods: A retrospective cross-sectional analytical study analyzing the relationship between BMI and endometrial biopsy results (obtained via endometrial sonohysteroscopy, medical abortion, and linear endometrial biopsy) in patients diagnosed with postmenopausal bleeding (PMB) and abnormal uterine bleeding (AUB) between January 2022 and 2025. Medical records from the gynecology department at Juan A. Fernández Hospital were analyzed.
Inclusion criteria: patients with AUB or PMB and abnormal ultrasound findings who underwent evaluation for endometrial pathology and for whom the pathological anatomy results were available. Exclusion criteria: asymptomatic patients with abnormal ultrasound findings or incomplete medical records. Biopsy results were categorized as “negative” (non-pathological findings) and “positive” for those showing malignant or premalignant pathology (carcinoma or atypical hyperplasia). The prevalence of endometrial pathology was calculated by comparing the biopsy positivity rate between patients with and without obesity; the median BMI was compared between patients with and without pathology. For statistical analysis, the chi-square test was used for the first objective, and the Mann-Whitney U test for the second. Statistical significance was set at p < 0.05.
Results: A total of 120 patients were included, with a median age of 54 years (range 26– 81 years), of whom 48% (n=58) had a BMI > 30 and 52% (n=62) had a BMI < 30.
Of these, 50% (n=60) tested positive for endometrial pathology and the other 50% (n=60) tested negative.
The prevalence of endometrial pathology in patients with a BMI > 30 was 67.2% (n = 39), while in patients with a BMI < 30 it was 33.8% (n = 21) (p = 0.000259)
The median BMI in patients with a positive biopsy was 33.15, and in patients with a negative biopsy it was 28.04 (p=0.000228)
Conclusion: Obese patients had a significantly higher prevalence of endometrial pathology compared to non-obese patients. Higher BMI was significantly associated with premalignant and malignant endometrial conditions.