The Clinical Significance of Subtle Distal Fallopian Tube Abnormalities: A Multicentre Prospective Observational Study

Background: Subtle distal fallopian tube abnormalities are a group of diseases characterised by small variations in tubal anatomy. The clinical significance of these abnormalities need to be studied. Objectives: The purpose of this multicentre prospective observational study was to investigate whether subtle distal fallopian tube abnormalities are related to infertility and endometriosis. Materials and Methods: The investigation was carried out in five medical centres in China and France from February to July 2021 and included reproductive-age patients who underwent gynaecological laparoscopy. Subtle abnormalities included Hydatid of Morgagni (HM) , fimbrial agglutination, tubal diverticula, accessory ostium, fimbrial phimosis, and accessory fallopian tube. Results: 642 patients were enrolled in the study and 257 (40.0%) were diagnosed with subtle tube abnormalities. Hydatid of Morgagni was the most common abnormality (22.7%; n=146), followed by fimbrial agglutination (19.8%; n=127), tubal diverticula (6.9%; n=44), accessory tube (2.0%; n=13), and tubal accessory ostium (1.9%; n=12). Fimbrial phimosis was the least common abnormality (0.3%; n=2). The prevalence of subtle fallopian tube abnormalities was significantly higher among infertile patients (188/375, 50.1%) than those without history of infertility (69/267, 25.8%, ᶍ2=38.332, P=0.000). 209 patients were diagnosed with endometriosis during surgery, and the prevalence of subtle abnormalities was significantly higher in the endometriosis group than in those without endometriosis (61.2%, 128/209 vs. 29.8% 129/433, ᶍ2=58.086, P=0.000). Conclusions: Higher prevalence of subtle tubal abnormalities suggests that they may contribute to infertility. They are highly related to endometriosis and indicate fimbrial abnormalities of endometriosis. What is new? This is the largest multicentre study to investigate the subtle distal fallopian tube abnormalities in infertile women. Compared to previous studies, this study includes the main subtle distal abnormalities and the control group patients without a history of infertility.