Fluid in a fallopian tube indicates damage or a blockage at the end portion of the fallopian tube, states the American Society for Reproductive Medicine. This condition is called hydrosalpinx, and it often causes fertility problems.
When a fallopian tube is blocked and filled with fluid, the chances of normal pregnancy are significantly reduced because the egg cannot pass through the tube to the uterus. Ectopic pregnancy may occur in the fallopian tube, which can be life-threatening, explains the American Society for Reproductive Medicine. If the fallopian tubes are completely blocked, fertility treatments may be required to achieve pregnancy.
Hydrosalpinx is sometimes caused by an old infection in the fallopian tube, a sexually transmitted infection, a previous surgery or endometriosis. Doctors can check for hydrosalpinx through an ultrasound, an X-ray or surgery, notes the American Society for Reproductive Medicine.