What is an ectopic pregnancy?
An ectopic pregnancy (EP) is a condition in which a fertilized egg settles and grows in any location other than the inner lining of the uterus. The vast majority of ectopic pregnancies is so-called tubal pregnancies and occurs in the Fallopian tube; however, they can occur in other locations, such as the ovary, cervix, and abdominal cavity. A molar differs from an ectopic in that it is usually a mass of tissue derived from an egg with incomplete genetic information that grows in the uterus in a grape-like mass that can cause symptoms to those of pregnancy.
The major health risk of ectopic pregnancy is rupture leading to internal bleeding. The survival rate from ectopic pregnancies is improving even though the incidence of ectopic pregnancies is also increasing. Failure to seek early medical attention is the major reason for a poor outcome. Ectopic pregnancy remains the leading cause of pregnancy-related death in the first trimester of pregnancy. In rare cases, an ectopic pregnancy may occur at the same time as an intrauterine pregnancy. This is known as heterotopic pregnancy. The incidence of heterotopic pregnancy has risen in recent years due to the increasing use of IVF (in vitro fertilization) and other assisted reproductive technologies (ARTs).
What are the risk factors for ectopic pregnancy?
There are multiple factors that increase a women's likelihood of having an ectopic pregnancy, but also it is important to note that ectopic pregnancies can occur in women without any of these risk factors.
A prior history of an ectopic pregnancy is the greatest risk factor for an ectopic pregnancy. The recurrence rate is very less after the first ectopic pregnancy than after the second.
Any disruption of the normal architecture of the Fallopian tubes can be a risk factor for a tubal pregnancy or ectopic pregnancy in other locations. Previous surgery on the Fallopian tubes such as tubal sterilization or reconstructive, procedures can lead to scarring and disruption of the normal anatomy of the tubes and increases the risk of an ectopic pregnancy. Likewise, infection, congenital abnormalities, or tumors of the Fallopian tubes can increase a woman's risk of having an ectopic pregnancy.
For ectopic pregnancy, Infection in the pelvis (pelvic inflammatory disease) is another risk factor. Pelvic infections are usually caused by sexually-transmitted organisms, such as Chlamydia or N. gonorrhoeae, the bacteria that cause gonorrhea. However, non-sexually transmitted bacteria can also cause pelvic infection and increase the risk of an ectopic pregnancy. Infection causes an ectopic pregnancy by damaging or obstructing the Fallopian tubes. Normally, the inner lining of the Fallopian tubes is coated with small hair-like projections called cilia. These cilia are important to transport the egg smoothly from the ovary through the Fallopian tube and into the uterus. If these cilia are damaged by infection, egg transport becomes disrupted. The fertilized egg can settle in the Fallopian tube without reaching the uterus, thus becoming an ectopic pregnancy. Likewise, infection-related scarring and partial blockage of the Fallopian tubes can also prevent the egg from reaching the uterus.
Because having multiple sexual partners’ increases a woman's risks of pelvic infections, multiple sexual partners also are associated with an increased risk of ectopic pregnancy. Like pelvic infections, conditions such as endometriosis, fibroid tumors, or pelvic scar tissue (pelvic adhesions), can narrow the Fallopian tubes and disrupt egg transportation, thereby increasing the chances of an ectopic pregnancy.
Cigarette smoking around the time of conception has also been associated with an increased risk of ectopic pregnancy. This risk was observed to be dose-dependent, which means that the risk is dependent upon the individual woman's habits and increases with the number of cigarettes smoked.
What are signs and symptoms of an ectopic pregnancy?
The classic signs and symptoms of ectopic pregnancy include:
- abdominal pain,
- the absence of menstrual periods (amenorrhea), and
- vaginal bleeding or intermittent bleeding (spotting)
The woman may not be aware that she is pregnant. These characteristic symptoms occur in ruptured ectopic pregnancies (those accompanied by severe internal bleeding) and non-ruptured ectopic pregnancies. However, while these symptoms are typical for an ectopic pregnancy, they do not mean an ectopic pregnancy is necessarily present and could represent other conditions. In fact, these symptoms also occur with a threatened abortion (miscarriage) in non ectopic pregnancies.
The signs and symptoms of an ectopic pregnancy typically occur six to eight weeks after the last normal menstrual period, but they may occur later if the ectopic pregnancy is not located in the Fallopian tube. Other symptoms of pregnancy (for example, nausea and breast discomfort, etc.) may also be present in ectopic pregnancy. Weakness, dizziness, and a sense of passing out upon standing can (also termed near-syncope) be signs of serious internal bleeding and low blood pressure from a ruptured ectopic pregnancy and require immediate medical attention. Unfortunately, many women with a bleeding ectopic pregnancy do not recognize they have symptoms of ectopic pregnancy. Their diagnosis is delayed until the woman shows signs of shock (for example, low blood pressure, weak and rapid pulse, pale skin and confusion) and often is brought to an emergency department; this situation is a medical emergency.
How is ectopic pregnancy diagnosed?
The first step in the diagnosis is an interview and examination by the doctor. The usual second step is to obtain a qualitative (positive or negative for pregnancy) or quantitative (measures hormone levels) pregnancy test. Occasionally, the doctor may feel a tender mass during the pelvic examination. If an ectopic pregnancy is suspected, the combination of blood hormone pregnancy tests and pelvic ultrasound can usually help to establish the diagnosis. Trans-vaginal ultrasound is the most useful test to visualize an ectopic pregnancy. In this test, an ultrasound probe is inserted into the vagina, and pelvic images are visible on a monitor. Trans-vaginal ultrasound can reveal the gestational sac in either a normal (intrauterine) pregnancy or an ectopic pregnancy, but often the findings are not conclusive. Rather than a gestational sac containing a visible embryo, the examination may simply reveal a mass in the area of the Fallopian tubes or elsewhere that is suggestive of, but not conclusive for, an ectopic pregnancy. The ultrasound can also demonstrate the absence of pregnancy within the uterus.
Pregnancy tests are designed to detect specific hormones; the beta subunit of human chorionic gonadotrophin (beta HCG) blood levels is also used in the diagnosis of ectopic pregnancy. Beta HCG levels normally rise during pregnancy. An abnormal pattern in the rise of this hormone can be a clue to the presence of an ectopic pregnancy. In rare cases, laparoscopy may be needed to ultimately confirm a diagnosis of ectopic pregnancy. During laparoscopy, viewing instruments are inserted through small incisions in the abdominal wall to visualize the structures in the abdomen and pelvis, thereby revealing the site of the ectopic pregnancy.
What is the health risk of an ectopic pregnancy patient?
Some women spontaneously absorb their ectopic pregnancy with no apparent ill effects, and can be observed without treatment. However, the true incidence of spontaneous resolution of ectopic pregnancies is unknown. It is not possible to predict which women will spontaneously resolve their ectopic pregnancies.
Rupture is the most feared complication of an ectopic pregnancy, leading to internal bleeding, pelvic and abdominal pain, shock, and even death. Therefore, bleeding in an ectopic pregnancy may require immediate surgical attention. Bleeding results from the rupture of the Fallopian tube or from blood leaking from the end of the tube as the growing placenta erodes into the veins and arteries located inside the tubal wall. Blood coming from the tube can be very irritating to other tissues and organs in the pelvis and abdomen, and result in significant pain. The pelvic blood can lead to scar tissue formation that can result in problems with becoming pregnant in the future. The scar tissue can also increase the risk of future ectopic pregnancies.
What treatment options are available for ectopic pregnancy?
Treatment options for ectopic pregnancy include observation, laparoscopy, laparotomy, and medication. Selection of these options is individualized. Some ectopic pregnancies will resolve on their own without the need for any intervention, while others will need urgent surgery due to life-threatening bleeding. However, because of the risk of rupture and potential dire consequences, most women with a diagnosed ectopic pregnancy are treated with medications or surgery.
For those who require intervention, the most common treatment is surgery. Two surgical options are available;
- laparotomy and
Laparotomy is an open procedure whereby a transverse (bikini line) incision is made across the lower abdomen. Laparoscopy involves inserting viewing instruments into the pelvis through tiny incisions in the skin. For many surgeons and patients, laparoscopy is preferred over laparotomy because of the tiny incisions used and the speedy recovery afterwards. Under optimal conditions, a small incision can be made in the Fallopian tube and the ectopic pregnancy removed, leaving the Fallopian tube intact. However, certain conditions make laparoscopy less effective or unavailable as an alternative. These include massive pelvic scar tissue and excessive blood in the abdomen or pelvis. In some instances, the location or extent of damage may require removal of a portion of the Fallopian tube, the entire tube, the ovary, and even the uterus.
Medical therapy can also be successful in treating certain groups of women who have an ectopic pregnancy. Medical treatment method involves the use of an anti-cancer drug called methotrexate (Rheumatrex, Trexall). This drug acts by killing the growing cells of the placenta, thereby inducing miscarriage of the ectopic pregnancy. Some patients may not respond to methotrexate, and will require surgical treatment. Methotrexate is gaining popularity because of its high success rate and low rate of side effects. There are certain factors, including the size of the mass associated with the ectopic pregnancy and the blood beta HCG concentrations that help doctors decide which women are candidates for medical rather than surgical treatment. The optimal candidates for methotrexate treatment are women with a beta-subunit (HCG) concentration less than or equal to 5000 mIU/mL.
Although there have been a few reported cases of women giving birth by cesarean section to live infants that were located outside the uterus, this is extremely rare. The chance of carrying an ectopic pregnancy to full term is so remote, and the risk to the woman so great, that it can never be advocated. It would be ideal if an ectopic pregnancy in the Fallopian tube could be saved by surgery to relocate it into the uterus.
Overall, there have been great advances in the early diagnosis and treatment of ectopic pregnancy, and the mortality from this condition has decreased dramatically.
Ectopic Pregnancy at a Glance
- An ectopic pregnancy is a pregnancy located outside the inner lining of the uterus.
- Risk factors for ectopic pregnancy include previous ectopic pregnancies and conditions (surgery, infection) that disrupt the normal anatomy of the Fallopian tubes.
- The major health risk of an ectopic pregnancy is internal bleeding.
- Diagnosis of ectopic pregnancy is usually established by blood hormone tests and pelvic ultrasound.
- Treatment options for ectopic pregnancy include both surgery and medication.