Adenomyosis and endometriosis are prevalent gynecological conditions that significantly impair the quality of life of millions of women worldwide [1,2]. These diseases share clinical manifestations such as dysmenorrhea, chronic pelvic pain, and infertility [1,3]. The symptoms not only cause physical discomfort but also lead to chronic stress, anxiety, and depression, profoundly affecting the psychological health of patients [3,4]. The co-occurrence of adenomyosis and endometriosis is frequently reported, with studies indicating that 20 % to 40 % of women with adenomyosis also suffer from endometriosis [[5], [6], [7]]. This suggests a potential shared genetic or environmental predisposition. Additionally, the clinical outcomes between patients with only adenomyosis and those with concurrent endometriosis may differ significantly. Patients with adenomyosis typically experience severe menstrual pain, which tends to be exacerbated in those with concurrent endometriosis due to more extensive inflammation and pelvic adhesions related to ectopic endometrial lesions [8,9]. However, the impact of these conditions on fertility varies across different studies in the literature. Some studies report that patients with both conditions have poorer reproductive outcomes, characterized by lower pregnancy rates and higher miscarriage rates [10]. However, in other research, the presence of adenomyosis has a negative impact on fertility outcomes, but the combination with endometriosis does not significantly increase this impact [11]. The exact effects of concurrent diseases on menstrual pain and reproductive health remain to be clarified.

Despite the significant overlap in clinical symptoms, the pathophysiological features of adenomyosis and endometriosis differ. Adenomyosis is defined by the presence of endometrial glands and stroma within the myometrium, leading to an enlarged and often painful uterus [12]. On the other hand, endometriosis involves the growth of endometrial-like tissue outside the uterus, typically affecting the ovaries, fallopian tubes, and pelvic peritoneum [9]. Both conditions share common pathophysiological pathways, including estrogen dependency and chronic inflammation, which contribute to their symptoms and disease progression [8,9]. In addition, demographic factors such as age, parity, and body mass index (BMI) play crucial roles in the manifestation and prognosis of these diseases. For instance, adenomyosis is more commonly seen in middle-aged women and those who have had children, whereas endometriosis is often diagnosed in younger women and may inversely correlate with parity [8,13,14]. The role of BMI also presents an intriguing paradox; while a higher BMI generally offers a protective effect against endometriosis, it may predispose individuals to adenomyosis [13].

Given the overlapping yet distinct nature of these conditions, our study aims to comprehensively analyze and compare the clinical and demographic characteristics of adenomyosis patients, with and without concurrent endometriosis. We also seek to explore the factors influencing the occurrence of endometriosis among patients with adenomyosis, thereby providing data support for future treatment strategies and patient management.