The fallopian tubes are two narrow, muscular tubes that connect each ovary to the uterus. They serve as the pathway an egg travels after ovulation and are the site where fertilization happens. Each tube measures about 9 to 11 centimeters long, roughly the length of a pen cap, and plays an active role in moving eggs, nourishing embryos, and facilitating the meeting of egg and sperm.
Structure and Segments
Each fallopian tube has four distinct segments, running from the ovary inward toward the uterus. At the outermost end sit the fimbriae: finger-like, hair-covered projections that drape over the surface of the ovary. During ovulation, the fimbriae become engorged with blood and pulse in sync with the heartbeat, sweeping across the ovary to capture the released egg. They funnel it into the next segment, the infundibulum, a small funnel-shaped opening.
From there, the egg enters the ampulla, the widest and longest section, making up more than half the tube’s total length. This is where fertilization typically takes place. The final segment, the isthmus, is a narrow channel that connects the tube to the wall of the uterus.
How Eggs Travel Through the Tubes
The inside of each tube is lined with two types of cells working together. Tiny hair-like structures called cilia beat rhythmically toward the uterus, creating a current that propels the egg forward. Alongside the ciliated cells, secretory cells release fluid that nourishes the egg and creates a slippery surface for transport. Animal studies suggest that ciliary action alone can move an egg to the fertilization site within a normal time frame, even when muscular contractions are disabled.
The tube’s smooth muscle layer adds a second transport system. It produces two types of contractions: short, frequent pulses that churn the egg and mix it with tubal fluid, and sustained contractions at key junctions that act like gates, temporarily pausing the egg’s journey. These pauses aren’t random. They allow the egg or early embryo to interact with nourishing tubal secretions and ensure the embryo arrives in the uterus at the hormonal moment most favorable for implantation. The muscular waves travel in both directions at about 1 to 2 millimeters per second, mixing rather than pushing, while the cilia handle the directional movement.
The Fertilization Site
Sperm that reach the fallopian tube typically meet the egg in the ampulla. Because this is the widest portion of the tube, it provides enough space for sperm to surround and penetrate the egg. After fertilization, the resulting embryo spends several days traveling through the remaining length of the tube, dividing as it goes, before entering the uterus for implantation. The tube’s tonic contractions at the junction with the uterus control when the embryo is released, timing its arrival to match peak uterine receptivity.
Common Conditions That Affect the Tubes
Because the fallopian tubes are narrow and internally delicate, they’re vulnerable to damage. Tubal problems account for roughly 30% to 40% of female infertility cases. The most common cause of blockage is infection from sexually transmitted bacteria, particularly chlamydia and gonorrhea, which trigger inflammation inside the tube (salpingitis). A single episode of pelvic inflammatory disease raises the chance of tubal damage to about 23%.
Other causes of blockage include endometriosis (where tissue similar to the uterine lining grows in the tubes or around them), scarring from previous abdominal or pelvic surgery, and, less commonly, congenital abnormalities. When a blocked tube fills with fluid, the condition is called hydrosalpinx. It rarely produces noticeable symptoms and is often discovered only during a fertility workup.
Ectopic Pregnancy
About 97% of ectopic pregnancies occur in a fallopian tube. This happens when damage or inflammation impairs the tube’s ability to move an embryo toward the uterus. The embryo gets trapped and implants in the tubal wall instead. Prior ectopic pregnancy is the strongest individual risk factor: the chance rises to about 10% after one occurrence and above 25% after two. Other risk factors include previous pelvic infections, smoking (which disrupts ciliary function), endometriosis, and a history of tubal surgery.
How Doctors Check for Blockages
The standard test for evaluating tubal health is a hysterosalpingogram, commonly called an HSG. During this procedure, a contrast dye is injected into the uterus while X-ray images are taken in real time. If the tubes are open, the dye flows through them and spills out the fimbriated ends, where the body absorbs it harmlessly. If the dye stops at a certain point, that indicates a blockage. The test also reveals the shape of the uterine cavity, which can help identify structural issues contributing to infertility.
Surgical Procedures Involving the Tubes
The two most well-known procedures are tubal ligation and salpingectomy, both forms of permanent contraception. Tubal ligation uses a band or clamp to close the tubes, while salpingectomy involves removing part or all of one or both tubes. Complete removal (bilateral salpingectomy) is the more effective option for preventing pregnancy and carries an additional benefit: research has linked it to roughly an 80% reduction in ovarian cancer risk. Scientists now believe that many ovarian cancers actually originate in the cells lining the fallopian tubes, which is why removing the tubes has such a significant protective effect.
A partial salpingectomy, removing a middle segment of the tube, is sometimes performed when full removal isn’t necessary. In cases of ectopic pregnancy or severe hydrosalpinx, removing the affected tube (unilateral salpingectomy) can preserve fertility on the opposite side while resolving the immediate problem.