Several factors can lead to blocked fallopian tubes:
1. Pelvic Inflammatory Disease (PID): Often caused by sexually transmitted infections (STIs), PID can result in scarring and blockage. 2. Endometriosis: This condition causes tissue similar to the uterine lining to grow outside the uterus, potentially blocking the tubes. 3. Previous Surgeries: Surgeries in the pelvic region, such as those for ectopic pregnancy or a ruptured appendix, can lead to adhesions that block the tubes. 4. Hydrosalpinx: A condition where the fallopian tube is filled with fluid, leading to blockage. 5. Congenital Defects: In rare cases, some women may be born with abnormalities in their fallopian tubes.