Prevalence of subtle distal Fallopian tube abnormalities and their association with endometriosis in infertility patients: a prospective cohort study.

Subtle distal Fallopian tube abnormalities comprise a group of diseases that are characterised by subtle variations in tubal anatomy. This prospective cohort study investigated the prevalence of subtle distal Fallopian tube abnormalities in the infertile population and their relationship with endometriosis. It was conducted in a single fertility referral centre between January 2017 and December 2018 and included all infertile patients who underwent laparoscopy. Subtle distal Fallopian tube abnormalities included fimbrial agglutination, tubal diverticula, accessory ostium, fimbrial phimosis, and accessory Fallopian tube. A total of 876 patients were enrolled in the study, and 251 cases (28.65%; mean age: 29.4 ± 4.7 years) were diagnosed with subtle tube abnormalities. A total of 179 of these cases presented only one type of abnormality, 62 presented two types of abnormalities, and 12 presented three types. Tubal fimbrial agglutination composed the largest group (62.2%;  = 156), followed by tubal diverticula (26.3%;  = 66), fimbrial phimosis (25.5%;  = 64), tubal accessory ostium (15.5%;  = 39), and tubal accessory ostium (15.5%;  = 39). An accessory Fallopian tube was the least common abnormity (4.8%;  = 12). A total of 70.9% (178/251) of the women with subtle tubal abnormalities had endometriosis. The prevalence of subtle distal Fallopian tube abnormalities in the stage I-II group was significantly higher than in the stage III-IV group (57.3% [149/260] vs. 20.9% [29/139];  < 0.001). These findings indicate the high prevalence of subtle distal Fallopian tube abnormalities in the infertile woman. This group of diseases is highly related to endometriosis and may indicate fimbrial abnormalities of endometriosis.