How Ectopic Pregnancies Are Found With Ultrasound

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If someone you know has had an ectopic or tubal pregnancy or you're worried that you're at risk for one, you might be wondering how doctors diagnose these pregnancies. We'll cover the diagnosis and treatment facts you need to know in this review.

Dangers of an Ectopic Pregnancy

An ectopic pregnancy, also called a tubal pregnancy, that develops undetected for too long can become life-threatening, especially if it leads to a ruptured fallopian tube or another such emergency. Not every ectopic pregnancy diagnosis, though, begins or ends in the emergency room. Sometimes, doctors can catch and treat these pregnancies earlier.

Many women who have a tubal pregnancy see their doctors after having bleeding or cramping in early pregnancy. Sometimes, these symptoms occur even in normal pregnancies, but at other times, they can be signs of miscarriage or ectopic pregnancy.

A doctor may specifically suspect ectopic pregnancy if a pelvic exam reveals an abnormal lump in the tubal area or if the woman is having excessive abdominal pain or tenderness.

If there is any sign of a ruptured tubal pregnancy, the woman should go straight to the emergency room, but in non-emergency cases, the doctor may run tests to confirm or rule out the possibility of a tubal pregnancy. The diagnosis includes a combination of hCG level testing and early ultrasound.

HCG Levels

The hCG levels in an ectopic pregnancy often rise slower than normal, meaning they will not double every two to three days in early pregnancy. This may be the first clue that leads the doctor to investigate the possibility of tubal pregnancy, but hCG levels on their own cannot confirm an ectopic pregnancy.

Slow-rising hCG can occasionally occur in a viable pregnancy or may also mean a first-trimester miscarriage. In addition, about 20% of ectopic pregnancies will have normally rising hCG levels, so doctors usually will order an ultrasound if there is a chance that the pregnancy may be ectopic.

Ultrasound for Diagnosis

If the ultrasound shows a gestational sac in the uterus, the doctor can most likely rule out tubal pregnancy as a cause of slow-rising hCG levels or bleeding and cramping. Other times, ultrasound will reveal the gestational sac and fetal pole (potentially with a heartbeat) being present in the fallopian tube, which obviously will lead to ectopic pregnancy diagnosis.

Frequently the sac will never be visible at all on ultrasound in a tubal pregnancy.

A transvaginal ultrasound showing no gestational sac with an hCG level above 1,500 is considered fairly certain evidence of an ectopic pregnancy. (On abdominal ultrasound, the sac should be visible by the time the hCG has reached 6,500.)

If the doctor confirms that the pregnancy is ectopic but there is no sign of rupture, the doctor may recommend treatment with methotrexate to terminate the pregnancy or may recommend monitoring the hCG levels if the pregnancy seems as if it may end naturally. If the doctor feels there is a significant risk that the ectopic pregnancy may rupture the tube, the treatment may be surgery to end the pregnancy.

A Word From Verywell

Tubal pregnancies are not viable and can be fatal if they are left untreated. While they are rare, they can pose serious risk to the mother. If you suspect you're experiencing an ectopic pregnancy, don't hesitate to immediately call your doctor to rule it out.

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