[Investigation of familial tendency of endometriosis]

Objective: To investigate the familial heritability of endometriosis and to compare the clinical characteristics of patients with or without a family history of endometriosis. Methods: From January 2020 to June 2022, 850 patients with endometriosis confirmed by laparotomy or laparoscopy in Peking University Third Hospital were included in this study. Clinical data were collected, family history was followed up, and the differences of clinical indicators between patients with and without family history of endometriosis were compared. Results: A total of 850 patients were enrolled, with an average age of (33.8±7.0) years old, 315 (37.1%, 315/850) patients in stage Ⅲ and 496 (58.4%, 496/850) patients in stage Ⅳ. There were 100 patients with family history of endometriosis, accounting for 11.8% (100/850). Most of the 113 relatives involved were mothers, daughters and sisters (76.1%, 86/113), 81.5% (22/27) of the second and third degree relatives were maternal relatives. The median ages of patients with and without family history of endometriosis were 30 and 33 years old respectively at the time of diagnosis. The unmarried rate of patients with family history was higher [42.0% (42/100) vs 26.3% (197/750)]. The percentage of dysmenorrhea patients with family history was higher [89.0% (89/100) vs 55.5% (416/750)]. The medians of dysmenorrhea score in patients with and without family history were 6 and 2, and the median durations of dysmenorrhea were 10 and 1 years. There were significant differences in age, marital status, percentage of dysmenorrhea, dysmenorrhea score and duration (all P<0.001). The median levels of serum cancer antigen (CA) 125 in patients with family history and patients without family history at the time of diagnosis were 57.5 and 46.9 kU/L respectively, with a statistically significant difference (P<0.05). However, there were no significant differences between the two groups in nationality, bady mass index, menarche age, menstrual cycle, menstrual period, menstrual volume, serum CA_19-9 level, cyst location and size, stage, history of adverse pregnancy and childbirth, infertility, adenomyosis and deep infiltrating endometriosis (all P>0.05). By comparing the specific conditions of dysmenorrhea patients with and without family history of endometriosis, there were no significant differences between the two groups in terms of the age of onset of dysmenorrhea, duration of dysmenorrhea, primary and secondary dysmenorrhea, and progressive aggravation of dysmenorrhea (all P>0.05). The difference in the degree of dysmenorrhea in dysmenorrhea patients with family history of endometriosis was significant (P<0.001). Conclusions: The incidence of endometriosis has a familial tendency, and most of the involved relatives are the first degree relatives. Compared with patients without family history of endometriosis, endometriosis patients with family history are diagnosed at an earlier age, with higher percentage of dysmenorrhea, had more severe dysmenorrhea and higher serum CA₁₂₅ level.