Fallopian tube test, endoscope view. The fallopian tube, the channel between the ovaries (one is seen at centre, white) and the uterus (upper right, pink), is swollen. To test if there is a blockage, methylene blue dye (blue) has been injected into the uterus. As the dye has emerged at the fimbrial end (the end nearest the ovary), this demonstrates that the tube is not blocked. Fallopian tubes can become blocked following infection or surgery, and this can lead to infertility if there is no passage for eggs to meet the sperm, or to reach the uterus.