The fallopian tubes are tubes present in female humans and female mammals that serve an extremely important purpose in fertilization. Essentially, they provide a connection between ovaries and the uterus. This allows for an egg or ovum to journey down the fallopian tube from an ovary into the uterus.

It is important to note that the fallopian tubes are not directly joined to the ovaries as they are often depicted in drawings. In fact they open into the peritoneal or abdominal cavity in very close proximity to the ovaries. They can even move prior to the ovulation each month. Some studies of the female reproductive system have captured pictures of the fallopian tubes lying on top of the uterus, instead of next to it on each side. Thus they are not the static tubes which form the familiar picture of the reproductive system in females.

During ovulation, however, the fallopian tubes are essentially the catchers of the egg. They will accept the egg and push it down the tube by using tiny follicles. The egg does not merely slide down to the uterus, but needs the work of the fallopian tubes to reach it.

Further, many people believe that fertilization of an egg occurs in the uterus. This is actually not the case. Fertilization occurs in the fallopian tubes, which then gently push the egg into the uterus. When the egg successfully attaches to the uterus, implantation occurs. Unsuccessful attachment of the fertilized egg results in a very early miscarriage, which tends to simply resemble a regular menstrual period. In fact, many women who have unsuccessful attachment of the fertilized egg never realize they were briefly pregnant.

Human females, upon reaching sexual maturity have quite differing sizes of fallopian tubes. They can be anywhere from 3-6 inches in length (about 7-15 cm). The fallopian tubes are made up of three layers: a mucous membrane inside the tubes, muscles outside the tubes, and serosa, which secretes mucus and allows for the passage of the egg into the uterus. It should be noted that generally, ovulation occurs in only one ovary in the human female, and thus only one fallopian tube receives an egg each month.

Problems with the fallopian tubes account for about 25% of infertility problems in women. The fallopian tubes can become scarred due to disease or to ectopic pregnancy, where a fertilized egg implants in a tube instead of in the uterus. Pelvic inflammatory disease, endometriosis, or a large ruptured cyst in the ovary may all cause scarring or blockage of either one or both fallopian tubes. If one tube is damaged, ability to get pregnant may be slightly reduced. If both tubes are damaged, fertilization problems can be very challenging.

Some surgeries on the fallopian tubes may help clear blockages. Alternately, many women with fallopian tube problems may chose to have in vitro fertilization. In this procedure, one or more fertilized eggs are placed directly into the uterus.