Association between insulin resistance and abnormal menstrual cycle in Chinese patients with polycystic ovary syndrome

Background Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder, which is characterized by insulin resistance (IR) and menstrual cycle disorders. IR is thought of as a pivotal cause of PCOS and related comorbidities. However, the link between IR and abnormal menstrual cycles in PCOS should be further studied. In this study, we clarified the dose–response relationship between IR and abnormal menstrual cycles in patients with PCOS. Results In this retrospective study including 140 patients with PCOS, we found that there was a dose–response relationship between the increased HOMA-IR index and the level of menstrual cycle disorders (1.61 [95%CI: 1.37–1.85] for normal menstruation, 2.02 [95%CI: 1.61–2.44] for oligomenorrhea, 2.35 [95%CI:1.96–2.75] for amenorrhea, P for trend = 0.003). Further stratification analyses showed that this dose–response relationship was more evident in the patients who were younger, had higher BMI, higher AFC numbers, elevated levels of testosterone, anti-Müllerian hormone, inhibin B, and prolactin levels, and had a lower progestogen level. Conclusions Our study has established an association between IR and abnormal menstrual cycles in patients with PCOS, which can be affected by age, BMI, and hormone levels. Our results might be helpful for further prevention and treatment of amenorrhea in PCOS.