An ectopic pregnancy doesn’t develop inside the uterus where it should. Instead, a fertilized egg implants somewhere else, most often in a fallopian tube. From the outside, early symptoms can look a lot like a normal pregnancy or even a miscarriage. On ultrasound, the defining feature is an empty uterus combined with a mass or ring-like structure near one of the tubes. Understanding what this looks like, both in terms of symptoms and imaging, can help you recognize the situation early and get the right care.
Where Ectopic Pregnancies Develop
About 92% of ectopic pregnancies occur in the fallopian tubes. Within the tube, the most common spot is the ampulla, the widest section closest to the ovary, which accounts for roughly 61% of tubal cases. The next most frequent site is the isthmus, the narrower portion closer to the uterus, at about 19%. The remaining cases implant in less typical locations: roughly 5% on an ovary, under 2% in the abdominal cavity, and less than 1% in the cervix.
Location matters because it affects how quickly symptoms appear and how dangerous a rupture can be. Pregnancies in the narrow isthmus tend to cause problems earlier because there’s less room for growth. Those in the wider ampulla may grow slightly longer before causing pain.
What the Symptoms Look Like
The textbook description is a combination of three things: a missed period (or positive pregnancy test), vaginal bleeding or spotting, and abdominal pain. In practice, only about 28% of people with an ectopic pregnancy actually have all three at once. Some women are even diagnosed before they’ve missed a period at all.
Early on, the symptoms can feel identical to a normal early pregnancy: mild cramping, light spotting, breast tenderness. What tends to shift the picture is one-sided pelvic or lower abdominal pain that feels sharper or more persistent than typical period cramps. The bleeding is often lighter than a normal period, more like brown or dark red spotting, and it comes from the uterine lining reacting to pregnancy hormones rather than from the ectopic site itself.
If the fallopian tube ruptures, the picture changes dramatically. Sudden, severe pain in the abdomen or pelvis is the hallmark. Shoulder pain is a classic warning sign that often surprises people. It happens because blood from the ruptured tube irritates the diaphragm, and the brain interprets that irritation as shoulder pain. Weakness, dizziness, or fainting from internal blood loss can follow quickly. A ruptured ectopic is a surgical emergency.
What It Looks Like on Ultrasound
On a transvaginal ultrasound, the first and most important finding is what’s not there: a pregnancy inside the uterus. When hormone levels are high enough that a normal pregnancy should be visible (generally above 1,000 to 2,000 mIU/mL on a blood test), an empty uterus raises immediate concern.
The ectopic pregnancy itself can appear in a few ways. The most recognizable is the “tubal ring sign,” a bright, ring-shaped structure surrounding a small dark center, sitting near the ovary or within the fallopian tube area. This sign has a 95% positive predictive value for an unruptured tubal ectopic, meaning when doctors see it, they can be highly confident of the diagnosis. In other cases, the ectopic may simply look like an irregular mass next to the ovary, sometimes with fluid visible in the pelvis from slow bleeding.
One tricky detail: the uterus sometimes creates a “pseudosac,” a fluid collection inside the uterine cavity that can be mistaken for a real early pregnancy. A true gestational sac has a thick, bright double-ring border and sits off-center within the uterine lining. A pseudosac tends to look elongated, has thinner tapered edges, and lacks any yolk sac or embryonic structure inside it. Telling them apart is critical because mistaking a pseudosac for a real pregnancy could delay the ectopic diagnosis.
How It’s Diagnosed
Diagnosis typically combines two tools: blood hormone levels and ultrasound. A pregnancy hormone (hCG) blood test is drawn, and if levels are above about 1,000 mIU/mL, a transvaginal ultrasound should be able to show a pregnancy sac inside the uterus. If the uterus is empty at that point, an ectopic pregnancy or a very recent miscarriage are the two main possibilities.
When hormone levels are still low, the picture is less clear. In those cases, the blood test is repeated 48 hours later. In a healthy early pregnancy, hCG levels roughly double every two days. If levels rise more slowly, plateau, or drop slightly, that pattern points toward either an ectopic or a failing pregnancy. Serial blood draws combined with repeat ultrasound narrow down the diagnosis over the following days.
Treatment Options
Treatment depends on the size of the ectopic pregnancy, hormone levels, and whether rupture has occurred. There are two main paths: medication or surgery.
Medication is an option when the ectopic is caught early, the mass is smaller than 3.5 cm, hormone levels are below about 2,000 mIU/mL, and there’s no detectable heartbeat. The medication stops the pregnancy from growing, and the body gradually absorbs the tissue. You’ll need follow-up blood tests over several weeks to confirm that hormone levels drop to zero. During this time, you may experience some abdominal pain and cramping as the tissue resolves, which can sometimes feel alarming but is expected.
Surgery becomes necessary when hormone levels are higher, the mass is larger, a heartbeat is detected, or the tube has already ruptured. The procedure is usually done laparoscopically through small incisions. In most cases, the affected fallopian tube is removed entirely. If the other tube is healthy, this doesn’t prevent future pregnancy. In some situations, the surgeon may open the tube and remove only the pregnancy tissue, preserving the tube itself, though this carries a slightly higher risk of another ectopic in the same tube later.
Fertility After an Ectopic Pregnancy
The odds of a successful pregnancy afterward are better than many people expect. In one study, about 83% of women who were treated for a tubal ectopic pregnancy went on to become pregnant again, with similar rates whether they had medication (82%) or surgery (85%). A larger population-based study found 24-month pregnancy rates of 76% after medication, 76% after tube-preserving surgery, and 67% after tube removal.
The timeline varies. Some studies report that about 57% to 67% of women achieve an intrauterine pregnancy within one to two years. Having one ectopic does increase the risk of having another one. Studies put the recurrence rate at roughly 15% to 24% over the following two years. Because of this, early monitoring with ultrasound is standard in any pregnancy that follows an ectopic, usually with a scan around six weeks to confirm the pregnancy is in the right place.
Losing a fallopian tube doesn’t cut your fertility in half the way many people assume. The remaining tube can pick up eggs released from either ovary, and many women conceive without difficulty. For those who do face challenges, fertility treatments remain effective options.