- What Is an Ectopic Pregnancy?
- What Causes Ectopic Pregnancy?
- What Are Risk Factors for Ectopic Pregnancy?
- What Are the Symptoms of an Ectopic Pregnancy?
- Can You Have a Period With an Ectopic Pregnancy?
- How Is Ectopic Pregnancy Diagnosed?
- What Is a Serum Human Chorionic Gonadotropin (hCG)?
- What Is a Transvaginal Ultrasound (TVUS)?
- How Is an Ectopic Pregnancy Treated?
- An ectopic pregnancy is a pregnancy that occurs outside the uterus (womb).
- All sexually active women of reproductive age are at risk of experiencing an ectopic pregnancy.
- Other than avoiding pregnancy, there is no way to 100% prevent an ectopic pregnancy.
- Several factors increase the risk of ectopic pregnancy, including endometriosis, fertility issues, advanced maternal age, smoking, and becoming pregnant with an IUD in place.
What Is an Ectopic Pregnancy?
An ectopic pregnancy is a pregnancy that occurs outside of the uterus (womb). In a normal pregnancy, the ovary releases an egg (ovulates) around day 14 of the menstrual cycle. If sperm is present, the egg may become fertilized. The fertilized egg then travels through the fallopian tube until it reaches the uterus, where it implants—or attaches—to the uterine lining.
In about 2% of pregnancies, however, the fertilized egg implants in structures outside of the uterus. The most common location is in the fallopian tube (referred to as a tubal pregnancy). Other possible implantation sites include:
- Fallopian tube: 90–95% of cases
- Cervix: 1% of cases
- Ovary: 1–3% of cases
- Previous Cesarean section scar: 1–3% of cases
A pregnancy that implants outside the uterus is called an ectopic pregnancy.
What Causes Ectopic Pregnancy?
The inside of the fallopian tubes is covered in tiny, hair-like structures called cilia. As they wave back and forth, the cilia help a fertilized egg move in only one direction—down the fallopian tube toward the uterus. Anything that damages these cilia (such as infection) or narrows the fallopian tube and blocks the egg (like scar tissue) means the egg may implant in the tube and continue to grow.
The uterus is a strong muscle that can stretch and accommodate an enlarging embryo. The fallopian tubes, on the other hand, have thin walls. Eventually, the growing egg can burst through the wall and cause internal bleeding. This is called a ruptured ectopic pregnancy.
In one study that looked at ectopic pregnancies between the years 2011–2013, ruptured ectopic pregnancies accounted for almost 3% of all pregnancy-related deaths. They were also the leading cause of death from heavy internal bleeding.
Pain associated with early pregnancy is presumed to be an ectopic pregnancy until proven otherwise.
What Are Risk Factors for Ectopic Pregnancy?
50% of women diagnosed with an ectopic pregnancy do not have any risk factors. However, there are several factors that can increase the chance of developing an ectopic pregnancy:
- Pelvic inflammatory disease (PID) and sexually transmitted infections (STIs).
- Fertility issues
- Advanced maternal age (AMA)
- Prior ectopic pregnancies
- Pelvic surgery
- Becoming pregnant with an intrauterine device (IUD) in place.
- Your mother took DES (diethylstilbestrol) while pregnant with you.
Ectopic pregnancies that occur in the fallopian tube are called tubal pregnancies. The most common risk factor for a tubal pregnancy is damage to the fallopian tube.
Pelvic Inflammatory Disease (PID) and Sexually Transmitted Infections (STI)
Pelvic Inflammatory Disease (PID) is an infection in the uterus, ovaries, or fallopian tubes. It is often a result of undiagnosed or untreated sexually transmitted infections (STI), like gonorrhea or chlamydia. These infections increase the risk of having an ectopic pregnancy in the future. Note that you may not always have symptoms with PID.
In endometriosis, the tissue that normally lines the inside of your uterus (called the endometrium) relocates and begins to grow on the ovaries, fallopian tubes, cervix, intestines, or abdominal wall. This tissue responds to menstrual cycle hormones and will bleed monthly, just like it would inside the uterus. This may cause inflammation and scarring of the fallopian tubes, which increases the risk of ectopic pregnancy.
The following increase your risk of ectopic pregnancy:
- Having infertility (independent of the treatment used to achieve pregnancy).
- Infertility due to fallopian tube problems.
- Use of assisted reproductive technology, such as in-vitro fertilization or embryo transfer.
If you undergo in-vitro fertilization, there is a 1 in 100 risk of having a heterotopic pregnancy. A heterotopic pregnancy occurs when an ectopic pregnancy and an intrauterine pregnancy occur at the same time. When you become pregnant without the use of assisted reproduction techniques, the risk is very small (ranges from 1 in 4,000 to 1 in 30,000 pregnancies).
Advanced Maternal Age (AMA)
Women 39 and older have a greater risk of developing an ectopic pregnancy than women aged 26 or younger. In a study published in 2001, it was found that the risk for ectopic pregnancy at 21 years of maternal age was 1.4%, whereas the risk at ≥44 years of age was 6.9%.
It is not clear what is driving this age-related increased risk. Studies suggest changes in the fertilized egg, as well as heightened risks of pelvic infections and tubal damage over time, are likely causes of increased risks.
Prior Ectopic Pregnancies
Women who have had a prior ectopic pregnancy are at increased risk of recurrence.
- With one prior ectopic pregnancy, your risk is 10%.
- With two or more prior ectopic pregnancies, your risk is 25%.
Pelvic surgeries—including tubal ligation for sterilization, a tubal ligation reversal, surgery to remove scar tissue, endometriosis surgery, or surgery for a ruptured ovarian cyst that is bleeding—can cause inflammation and scarring of the fallopian tubes. This scarring increases the risk for ectopic pregnancy.
The toxins and chemicals found in cigarette smoke may slow down movement within the fallopian tubes. Since the fertilized egg will implant after about seven days, it is important that it moves quickly through the tubes and makes it to the uterus by the end of that seven-day period. Failing to do so will lead to implantation within the tube.
Becoming Pregnant With an Intrauterine Device (IUD) in Place
Women with intrauterine devices (IUD) have a much lower risk of ectopic pregnancy. This is because these devices are very effective in preventing pregnancy from occurring in the first place. IUDs are excellent forms of contraception (birth control). However, if you do happen to become pregnant with an IUD in place, there is a 53% chance you will experience an ectopic pregnancy.
One study examined the relationship between ectopic pregnancy and IUDs. Pooled data from clinical studies of different types of IUDs showed that those with copper IUDs had the lowest risk of ectopic pregnancy. Those with progesterone-releasing IUDs had the highest risk.
The study’s author felt that the increased risk of ectopic pregnancies in those with IUDs was due to three factors:
- The IUD causes irritation of the fallopian tubes, and the resulting inflammation may prevent the egg from implanting into the uterus.
- It is possible that an IUD can only prevent intrauterine pregnancy, not ectopic pregnancy.
- Bacteria introduced at the time of IUD insertion may cause fallopian tube infection, which increases the risk of ectopic pregnancy.
The classic signs of ectopic pregnancy are a missed period, abnormal vaginal bleeding, and abdominal or pelvic pain.
What Are the Symptoms of an Ectopic Pregnancy?
Symptoms of an ectopic pregnancy can vary based on the location of the pregnancy, how far along it is, and whether a rupture occurs. The classic three signs are a missed period, abnormal vaginal bleeding, and abdominal or pelvic pain.
If your periods are irregular, you may not recognize when you have a missed period. If you are sexually active and experience abdominal pain, take a pregnancy test. If you are pregnant, see your doctor immediately. Pain associated with early pregnancy is presumed to be an ectopic pregnancy until proven otherwise.
Another sign of an ectopic pregnancy is abnormal vaginal bleeding. Sometimes, vaginal bleeding is the only sign of an ectopic pregnancy.
In some cases, an ectopic pregnancy may feel like a typical pregnancy and cause some of the same signs and symptoms, such as:
- A missed menstrual period
- Tender breasts
- An upset stomach
- Abnormal vaginal bleeding or implantation bleeding (as the fertilized egg implants into the uterus)
- Low back pain
- Mild pain in the abdomen or pelvis
- Mild cramping on one side of the pelvis
At this stage, it may be hard to know if you are experiencing a typical pregnancy or an ectopic pregnancy. Your doctor can do tests to help make a diagnosis.
As an ectopic pregnancy grows, more serious symptoms will develop, especially if a fallopian tube ruptures. Symptoms may include the following:
- Sudden, severe pain in the abdomen or pelvis (50% of women have no pain until the fallopian tube ruptures).
- Shoulder pain: occurs when blood in the pelvis irritates a nerve that causes shoulder pain.
- Weakness, dizziness, or fainting due to internal bleeding.
A ruptured ectopic pregnancy can cause life-threatening internal bleeding. If you have sudden, severe shoulder pain or dizziness and weakness, you should go to the emergency room immediately.
Can You Have a Period With an Ectopic Pregnancy?
No, you cannot have a period when you are pregnant—whether with an ectopic or a normal pregnancy. Some women have vaginal bleeding that may seem like a period. However, this is a different kind of bleeding and is not the same as menstruation.
Bleeding can occur during pregnancy for many reasons, such as infection, impending miscarriage, implantation as the egg burrows into the uterus, hormone fluctuations, and ectopic pregnancy.
How Is Ectopic Pregnancy Diagnosed?
The most critical factor in diagnosing an ectopic pregnancy is that your doctor to considers this a possible diagnosis. The minimum evaluation for a suspected ectopic pregnancy is to:
- Calculate how far along you are in your pregnancy (based on your last normal menstrual period).
- Check a blood pregnancy test (serum human chorionic gonadotropin, or hCG).
- Perform a transvaginal ultrasound.
What Is a Serum Human Chorionic Gonadotropin (hCG) Pregnancy Test?
There are several types of pregnancy tests. Every sexually active woman of reproductive age should be screened for pregnancy, regardless of whether she is using contraception. This is especially true if she has risk factors for possible ectopic pregnancy.
In most cases, you will have a positive pregnancy test with an ectopic pregnancy.
The most common type of pregnancy test is a urine pregnancy test. This includes at-home pregnancy test kits. A urine pregnancy test correctly identifies pregnancy 99% of the time. In the very early stages, when the pregnancy hormone level is less than 25 IU/mL, the test will result negative, even though you are pregnant. This is called a false-negative result. The incidence of ectopic pregnancy with a negative urine pregnancy test is 1.6%.
The next kind of pregnancy test is a blood test that comes back either positive or negative for pregnancy. This is called a qualitative serum (blood) hCG test.
A quantitative serum hCG (blood pregnancy hormone level) is more helpful in the case of an ectopic pregnancy. This is because it not only tells you if you are pregnant, but it also determines the amount of pregnancy hormone present in your body. Knowing your pregnancy hormone (serum hCG) level can help in several ways:
- You can see if the hCG level corresponds to how far along the pregnancy is based on your last normal menstrual period.
- Your hCG levels can be followed to see if they are increasing normally.
- Once your hCG level reaches 3000 mIU/mL, a normal pregnancy (if present) should be visible on ultrasound.
In the early stages of pregnancy, serum hCG levels normally increase by a certain amount every 48 hours. The amount of this increase depends on where the initial hCG level starts.
For example, if your initial serum hCG level starts at 1,500 mIU/mL, it should double to 3,000 mIU/mL over the next two days. If it doesn’t double, it may indicate an abnormal pregnancy, such as a miscarriage or ectopic pregnancy.
A decreasing hCG level also suggests an abnormal pregnancy. This must be followed carefully until it becomes negative. Note that ectopic pregnancies can still rupture even when hCG levels are low (lower than 25 IU/mL) and decreasing.
What Is a Transvaginal Ultrasound (TVUS)?
The term “transvaginal” means “through the vagina.” As its name suggests, transvaginal ultrasound (TVUS) is a procedure where an ultrasound probe is gently inserted about 2 or 3 inches into the vagina. This allows a doctor to thoroughly examine the uterus, fallopian tubes, ovaries, cervix, and pelvic area.
Ultrasounds can return one of three results:
- No pregnancy identified either inside or outside the uterus: very early pregnancy, too early to be seen.
- Pregnancy identified inside the uterus: normal pregnancy.
- Pregnancy identified outside the uterus: ectopic pregnancy.
What if My Pregnancy Is Not Seen on Ultrasound?
When a pregnancy is not seen on ultrasound (also called sonogram), this means your pregnancy is extremely early. It is simply too early to know what is going on with your pregnancy. To avoid interrupting a potentially normal pregnancy, if you are stable, you and your doctor may decide to wait and monitor you closely. You will need repeat blood tests and ultrasound every few days.
Pregnancy hormone levels (hCG) must be at least 2,000 mIU/mL before you can see a normal pregnancy in the uterus. For some pregnancies, that number may be higher. For twins or more, for instance, the pregnancy hormone level will need to be higher than normal before it can be seen on ultrasound.
If your pregnancy hormone level is less than 2000 mIU/mL, waiting 48 hours and repeating your level allows time to confirm the diagnosis. If the HCG level does not increase appropriately and the sonogram couldn’t identify a pregnancy, then an ectopic pregnancy is likely.
For twins, the pregnancy hormone level will need to be higher than normal before it can be seen on ultrasound.
How Is an Ectopic Pregnancy Treated?
There are three treatment options for ectopic pregnancy:
- Watchful waiting.
- Medical therapy with a drug called methotrexate.
- Surgical removal of the ectopic pregnancy.
The decision to use one treatment over another is based on multiple factors. Note that it is impossible to save an ectopic pregnancy and reimplant it into the uterus.
What Is Watchful Waiting?
Sometimes, diagnosing an ectopic pregnancy is not straightforward. When hCG levels are low (<2,000 mIU/mL) and the TVUS is negative, it can be hard to know if this is an early normal healthy pregnancy, an impending early pregnancy loss, or an ectopic pregnancy.
Many cases of ectopic pregnancy will spontaneously resolve. “Watchful waiting’’ and following serial hCG levels can help separate true cases of ectopic pregnancies from those that are spontaneously resolving. If you are clinically stable, waiting and closely following your levels can help confirm the diagnosis, guide management, and avoid unnecessary exposure to methotrexate.
Rechecking an hCG level in 12–24 hours can reveal three situations:
- The hCG level is increasing, making a repeat TVUS more helpful in making a diagnosis.
- The hCG level decreased by 50% or more. In this case, you do not have a healthy pregnancy, but you may not need treatment. You can continue to be monitored closely with repeated hCG levels. If they continue to decline and finally become negative, then you require no further treatment.
- The hCG level decreases by only a small amount or plateaus (doesn’t change). In this case, you still are at risk for an ectopic pregnancy. One study showed that only 7% of women with ectopic pregnancies had hCG decreases of more than 50%. The majority (55.6%) saw a decrease of just 10% in their hCG levels. Treatment here must be based on the development of symptoms, strong risk factors, or a high risk of suspicion.
It is impossible to save an ectopic pregnancy and reimplant it into the uterus.
What Is Methotrexate?
Methotrexate was originally developed as a cancer drug. It works by targeting growing cells to prevent them from replicating. Cancer is a condition in which cells are rapidly dividing; the same occurs in a growing embryo.
Methotrexate therapy has become the treatment of choice in ectopic pregnancies and is an option for women who:
- Want to avoid surgery.
- Have a confirmed or highly suspicious diagnosis of ectopic pregnancy.
- Are very stable (normal blood pressure, normal heart rate, no active bleeding).
- Have an unruptured ectopic that is small (<3–3.5cm).
- Do not have a fetal heartbeat on sonogram.
- Have an hCG level of less than 5,000 mIU/mL.
- Have no medical reasons to avoid methotrexate.
- Are dependable and will be sure to have their hCG levels monitored (for possibly up to 8 weeks).
Methotrexate is given as an intramuscular injection, usually in the buttocks. There are different protocols for using methotrexate, depending on your initial pregnancy hormone level and the rate at which this level decreases.
Generally, an injection of methotrexate is given on day 1, then hCG levels are measured 4 and 7 days later. If the levels decrease by 15%, then weekly hCG levels are drawn until they become negative.
If the hCG levels decrease by less than 15%, you and your doctor will decide if you want to receive a second injection of methotrexate or proceed with surgery. If a second dose of methotrexate is given, you return again for another check of your pregnancy hormone levels.
If your ectopic pregnancy does not respond to methotrexate, the dose may be repeated. However, most doctors won’t administer more than two doses. Surgery will likely be encouraged if you require a third dose.
Reported success rates are high with methotrexate treatment, but they mostly depend on your initial hCG levels. Reported success rates are 98.3% for initial hCG levels <1,000 mIU and 68.2% for levels >15,000 mIU. The success rate for receiving multiple doses is 92.7% and 88.1% for a single dose.
When Should You NOT Take Methotrexate?
You should not take methotrexate if:
- You have an intrauterine pregnancy or are breastfeeding.
- Your immune system is compromised.
- You have low blood cell counts.
- You have active lung or ulcer disease.
- Your liver or kidneys aren’t functioning well.
- Your ectopic pregnancy has ruptured or has a heartbeat on ultrasound.
- You are clinically unstable and may have internal bleeding.
- You refuse to accept a life-saving blood transfusion if necessary.
- You aren’t willing or able to follow up closely.
What Are Some of the Risks of Methotrexate?
There are several risks associated with taking methotrexate.
- After treatment with methotrexate, there is still the possibility of ectopic rupture. It is important to look out for an increase in pelvic pain, lightheadedness, or dizziness and contact your provider immediately if you experience them.
- You must avoid vigorous activities and sexual intercourse for at least two weeks after your last methotrexate injection or until your hCG levels are negative.
- You need to avoid folic acid supplements, foods containing folic acid, and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, Motrin, Advil, and Aleve. This is because they decrease the effectiveness of methotrexate.
- You must avoid alcohol until your hCG level returns to negative.
- You should stay out of the sun and avoid tanning for at least 7 days after your last injection because of the risk of a methotrexate-related inflammatory skin condition.
- Methotrexate has the potential to cause fetal death and birth defects. You should avoid becoming pregnant for at least 3 months after your last methotrexate injection. You must use effective contraception during this time.
- Some women feel tired, nauseous, or have trouble sleeping after methotrexate injections. You may also have abdominal pain or cramping, diarrhea, vomiting, sores in your mouth, or headache.
- Rarely, methotrexate may cause hair loss; suppress your bone marrow from making blood cells; cause lung inflammation, skin inflammation, or inflammation of the membrane covering the eye; or temporarily cause a problem with your liver. Call your provider if you see blood in your vomit, develop mouth sores, have unusual bleeding or bruising, see blood in your urine, or have black, tarry stools.
Methotrexate therapy allows you to avoid the risks of surgery and anesthesia. Methotrexate also allows you to preserve and not lose your fallopian tube. However, it has a lower success rate and requires longer follow up and more serial blood work than surgical treatment.
When Is Surgery Necessary to Treat an Ectopic Pregnancy?
Surgery is necessary when:
- Your blood pressure and heart rate are unstable (suggesting internal bleeding).
- Your pain level remains high (signals an ongoing rupture).
- Methotrexate is contraindicated, or medical management with methotrexate has failed.
- You want a tubal ligation or removal of a damaged tube when the ectopic is surgically removed.
Surgery can be performed through a minimally invasive procedure called a laparoscopy if you are stable. If you are unstable and experiencing internal hemorrhage, major surgery may be needed, as this allows the fastest access to the bleeding.
There are two surgical options for ectopic pregnancy. The entire fallopian tube containing the ectopic can be removed (called a salpingectomy). Alternatively, the ectopic pregnancy itself can be removed, while the affected tube is left behind (salpingostomy).
The decision to undergo a tubal repair (salpingostomy) vs. tubal removal (salpingectomy) depends on:
- How clinically stable you are.
- Your future fertility plans.
- The extent of damage to the fallopian tube.
Salpingectomy is often the preferred technique when there is severe damage to the fallopian tube, bleeding at the site of the rupture, or the fallopian tube on the opposite side looks healthy. If you desire a future pregnancy but the tube on the opposite side is damaged, then salpingostomy may be considered.
How Can I Prevent Having an Ectopic Pregnancy?
There are several ways you can help prevent ectopic pregnancy.
Reduce Your Risk of STIs
You should always use a condom during sex to reduce your risk of contracting an STI. Limiting your number of sexual partners can also reduce your risk of exposure.
Get Immediate Treatment for Infections
If you do get an STI, it’s important to get treated right away. The sooner you are treated, the less likely you are to develop inflammation that may damage your reproductive system and increase your risk of developing an ectopic pregnancy in the future. Some infections are asymptomatic, so it is a good idea to get tested regularly if you are sexually active.
Smoking is thought to increase the risk of having an ectopic pregnancy. The more you smoke, the higher your risk, so if you can’t quit, even reducing the number of cigarettes you smoke may be beneficial.
When to See a Doctor
There are other factors that may put you at a higher risk of developing an ectopic pregnancy. If any of the following risk factors apply to you, it is especially important that you see a doctor as soon as you think you may be pregnant.
- You have had a previous ectopic pregnancy.
- You become pregnant with an IUD in place.
- You become pregnant after having a tubal ligation.
- You have been diagnosed with fallopian tube abnormalities.
- You have had fertility problems or have had IVF or embryo transfer.
- Your mother took the chemical DES (diethylstilbestrol) while pregnant with you.
Finally, remember that half of women diagnosed with an ectopic pregnancy have no identifiable risk factors. All sexually active women of reproductive age are at risk of experiencing an ectopic pregnancy. Other than avoiding pregnancy, there is no way to 100% prevent an ectopic pregnancy.
Use birth control if you aren’t actively trying to conceive, and see your provider right away if you suspect that you may be pregnant. A ruptured ectopic pregnancy is an emergency condition and can be potentially life-threatening, so be sure to seek medical care immediately if you suspect you have an ectopic pregnancy.
Only 1-2% of pregnancies in the United States are ectopic, yet these pregnancies account for 3-4% of pregnancy related deaths(CDC). You must get medical care for treatment of suspected ectopic pregnancy.
Written by: Lisa Shephard, MD | Editor: Victoria Menard and Dayna Smith MD | Reviewed February 7, 2022 | Copyright myObMD. Media, LLC, 2022
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