The fertilization of the egg and sperm happens in the fallopian tube. Hency patency and normal functioning of at least one tube is required to conceive naturally.
The tubes can be tested by doing an HSG where a radio opaque dye is put in the uterine cavity and X Rays are taken. If the tubes are open, the dye is seen coming out of the fimbrial ends.
Laparoscopy / Hysteroscopy is a sure way of assessing the fallopian tubes and a corrective surgery can also be performed at the same sitting.
The tubes may be affected because of infection of the pelvis either chlamydia or tuberculosis, previous appendectomy. Sometimes the fallopian tube may be removed due to severe hydrosalpinx prior to IVF or due to an ectopic pregnancy. Badly damaged tubes generally require ART i.e IVF for conception.