To describe the frequency and risk factors of endometrial hyperplasia (EH) in infertile women undergoing their first IVF/ICSI treatment.

A total of 3198 infertile women undergoing their first IVF/ICSI cycle were recruited retrospectively from a fertility treatment center. Endometrial scratching and biopsy were conducted before IVF/ICSI treatment. The relationship between EH and clinical characteristics were analyzed.

EH without atypia, atypical hyperplasia, and endometrial cancer (EC) were diagnosed in 94 (2.94%), three (0.093%), and two (0.063%) women, respectively. The frequencies of EH were higher in patients with abnormal uterine bleeding (i.e. menstrual cycle irregularity in terms of frequency, volume, or length; 6.8% vs. 1.6%, P < 0.001, OR = 4.42), obesity (4.1% vs. 2.7%, P = 0.044, OR = 1.55), and elevated fasting glucose (4.6% vs. 2.5%, P = 0.017, OR = 1.85). In the multivariate analyses, all the three factors (abnormal uterine bleeding, obesity, elevated fasting glucose) were independently associated with risk of EH. In the subgroup analysis, among women with abnormal uterine bleeding, the frequency of EH in the elevated fasting glucose group was 10.7%, which was higher than that of the normal fasting glucose group (5.6%), even after adjustment for BMI (P = 0.014, OR = 1.53).

The frequency of EH in infertile women undergoing their first IVF/ICSI treatment was approximately 3%. Elevated fasting glucose was an independent risk factor for EH in infertile women undergoing IVF/ICSI.