A tubal pregnancy is a pregnancy that implants inside a fallopian tube instead of the uterus. It accounts for the vast majority of ectopic pregnancies, roughly 97% of them, and occurs in about 1% to 2% of all pregnancies. A tubal pregnancy cannot develop into a viable pregnancy and, if left untreated, can rupture the fallopian tube and cause life-threatening internal bleeding.
How a Tubal Pregnancy Happens
After an egg is fertilized, it normally travels through the fallopian tube and into the uterus, where it implants in the uterine lining. This journey depends on two things working together: tiny hair-like structures called cilia that beat in a coordinated wave, and smooth muscle contractions that push the embryo along. The interaction between the embryo and the cells lining the tube also plays a role in timing this process correctly.
When something disrupts any part of this system, the embryo can get stuck in the tube. It then begins to implant in the tubal wall, which is not designed to support a growing pregnancy. The tube is narrow and inelastic, so as the pregnancy grows, it stretches the tissue until it eventually causes pain, bleeding, or rupture.
Risk Factors
The most common underlying cause is damage or scarring in the fallopian tubes. Sexually transmitted infections like chlamydia and gonorrhea are major culprits, especially when they lead to pelvic inflammatory disease. These infections can scar the inside of the tube, narrowing the passage or disrupting the cilia that move the embryo forward.
Other factors that increase risk include:
- Previous ectopic pregnancy: Having one raises the chance of it happening again, particularly if the original risk factors are still present.
- Prior tubal surgery: Including tubal ligation (having your tubes tied) or surgery to repair a damaged tube.
- Endometriosis: Tissue growing outside the uterus can affect the fallopian tubes’ structure and function.
- Smoking: Associated with impaired tubal function.
- Assisted reproductive technology: Risk increases with certain IVF protocols, particularly with fresh embryo transfers and transfers done at the cleavage stage (day 3).
That said, many people who develop a tubal pregnancy have no identifiable risk factors at all.
Symptoms and Warning Signs
Early on, a tubal pregnancy feels like any other pregnancy. You may have a missed period, breast tenderness, and nausea. There’s often nothing to distinguish it in the first few weeks.
As the embryo grows, the first warning signs are typically light vaginal bleeding and pelvic pain, usually on one side. These symptoms can be subtle enough to mistake for a normal early pregnancy or even a period. The timing varies, but symptoms generally become more noticeable as the pregnancy progresses through weeks 5 to 8.
If the tube begins to leak blood or ruptures, the situation becomes an emergency. Blood pooling in the abdomen can irritate the diaphragm, causing shoulder pain, which is a hallmark sign many people don’t expect. You may also feel a strong urge to have a bowel movement, lightheadedness, or fainting. These signs indicate internal bleeding and require immediate medical attention.
How It’s Diagnosed
Diagnosis usually involves two tools: blood tests measuring pregnancy hormone levels and a transvaginal ultrasound.
In a healthy early pregnancy, the pregnancy hormone (hCG) roughly doubles every two to three days. In a tubal pregnancy, hCG levels typically rise much more slowly, with a doubling time that stretches beyond 2.2 days. This sluggish rise is one of the earliest clues that something is wrong, especially before an ultrasound can show anything definitive.
On ultrasound, doctors look for a pregnancy sac inside the uterus. When the uterus is empty but a mass appears near the fallopian tube, that raises strong suspicion. The most definitive finding is seeing a gestational sac containing a yolk sac or embryo outside the uterus. Sometimes the mass appears as a ring-shaped structure around an empty sac, sometimes called a “bagel sign,” which is also highly predictive. In other cases, the mass looks more irregular, which still raises concern and prompts further monitoring or intervention.
Treatment Options
A tubal pregnancy is treated one of two ways: medication or surgery. The right approach depends on how early it’s caught, the size of the mass, hormone levels, and whether the tube has ruptured.
Medication
When a tubal pregnancy is caught early and the tube hasn’t ruptured, medication can be used to stop the pregnancy from growing so the body reabsorbs the tissue over time. This approach is generally considered when the mass is smaller than about 3.5 to 4 centimeters and hormone levels are below certain thresholds. After treatment, you’ll need follow-up blood tests over several weeks to confirm that hormone levels are dropping back to zero. The advantage is that it avoids surgery and preserves the fallopian tube, which tends to result in better tubal function afterward compared to surgical options.
Surgery
Surgery is necessary when the pregnancy is larger, hormone levels are high, or the tube has already ruptured. There are two main procedures. A salpingostomy involves making a small incision in the tube, removing the pregnancy, and leaving the tube in place. This preserves the tube for potential future use, but carries a 5% to 29% risk of persistent ectopic tissue that may need additional treatment. A salpingectomy removes the affected tube entirely along with the pregnancy. This is typically recommended when the tube has ruptured, when the pregnancy is in the narrow middle section of the tube (where bleeding risk is higher), or when the tube is too damaged to salvage.
The choice between these procedures depends on the condition of the tube, the location of the pregnancy within it, your desire for future fertility, and your ability to attend follow-up appointments to monitor for persistent tissue if the tube is preserved.
Recovery and Future Fertility
Physically, recovery from medication takes several weeks of monitoring. Surgical recovery, particularly from minimally invasive laparoscopic procedures, generally takes a few weeks before returning to normal activity.
The question most people have after a tubal pregnancy is whether they can get pregnant again. The answer for most people is yes. Research following large groups of women in North America and Europe shows that 60% to 70% of women become pregnant within two years of treatment for an ectopic pregnancy. Live birth rates range from 50% to 65%, though there’s significant variability depending on individual factors like the health of the remaining tube and the treatment method used.
Conception with a single healthy tube is entirely possible. Ovulation alternates between the two ovaries, and the remaining tube can sometimes pick up an egg released from either side. Women treated with medication rather than surgery tend to retain more tubal function, since both tubes remain intact. However, if underlying risk factors like scarring or infection are present, the chance of another ectopic pregnancy is higher regardless of treatment method. Between 50% and 80% of women who try to conceive after a tubal pregnancy will become pregnant again within two years, assuming no other serious fertility issues are present. For those who have difficulty conceiving naturally, IVF bypasses the fallopian tubes entirely and remains an effective option.