Ectopic pregnancy

• What is Ectopic Pregnancy?
• Statistics
• Risk Factors
• Progression
• Symptoms
• Clinical Examination
• How is it Diagnosed
• Prognosis
• Treatment
• References

What is Ectopic Pregnancy?

 

Ectopic pregnancy (sometimes referred to as extrauterine pregnancy) refers to a pregnancy which grows outside of the uterus (where pregnancy usually occurs). It occurs when a fertilised egg fails to implant in the endometrial tissues of the uterine cavity and instead leaves the uterus and implants at another site. The most common sites for such pregnancies are the: Fallopian tubes (also known as tubal pregnancy); Ovary; and Abdominal cavity (i.e. the area around the abdomen including the liver and spleen).

Left untreated, ectopic pregnancy is a life threatening condition. It is the leading cause of death in the first trimester of pregnancy and the fourth leading cause of all maternal deaths in the United Kingdom. Ectopic pregnancy is also a leading cause of early pregnancy death in Australia. In the 2003-05 period, there were two women who died directly as a result of pregnancy in the first trimester and one of these deaths was caused by an ectopic pregnancy.

Statistics

Women of childbearing age are at risk of ectopic pregnancy and is estimated that 2% of all pregnancies are ectopic. While incidence is now stable or declining in many developing countries, it increased markedly 1970-1990 and remains well above 1970s levels today. For example in England ectopic pregnancies occurred at a rate of 3.45 per 1000 live births in 1966.  In 1996 the rate had increased to 15.5 per 1000 live births.

In Australia the incidence of ectopic pregnancy decreased slightly in the 1990s, from a rate of 17.4 per 1000 births in 1990 to 16.2 per 1000 in 1998.

Increasing incidence is in part due to improvements in the way ectopic pregnancy is diagnosed (e.g. ultrasound, which is the usual way to diagnose ectopic pregnancy today, was much less accessible several decades ago). Other factors thought to play a role in the changing incidence of ectopic pregnancy include changes in smoking patterns in women and increased incidence of pelvic inflammatory disease (PID) and chlamydia trachomatis, a sexually transmitted infection (STI).

Risk Factors

There are a number of behaviours, experiences and diseases which increase a woman’s risk of ectopic pregnancy. These relate mainly to a woman’s sexual and reproductive history, however smoking also poses a significant risk. The following factors are independently associated with an increased risk of ectopic pregnancy:

• Smoking: A French study reported that cigarette smoking accounted for 35% of the risk associated with ectopic pregnancy. The more a woman smokes, the more likely she is to develop an ectopic pregnancy. Women who smoke more than 20 cigarettes per day are almost four times more likely to experience an ectopic pregnancy than those who have never smoked. Women who smoke less than 10 cigarettes per day are less than 2 times more likely to develop ectopic pregnancy than those who never smoked;
• Previous ectopic pregnancy: Women who have had one ectopic pregnancy in the past are about seven times more likely to develop an ectopic pregnancy in the future than women who have never had an ectopic pregnancy. Women who have had two or more ectopic pregnancies in the past are over 70 times more likely to develop an ectopic pregnancy in the future;
• Previous miscarriage: The risk of ectopic pregnancy increases with the number of miscarriages a woman has previously experienced. Women who have experienced 1-2 miscarriages in the past are 1.2 times more likely to develop an ectopic pregnancy than women who have never miscarried. Three or more miscarriages in the past increases the risk of developing an ectopic pregnancy to three times that of women who have never had a miscarriage;
• Previous medically induced abortion: Women who have medically terminated a pregnancy are 2.8 times more likely to experience ectopic pregnancy than those who had never induced abortion. There is no increased risk associated with a history of induced surgical abortion;
• History of pelvic inflammatory disease: Pelvic inflammatory disease (PID) often leads to scarring and deformation of the pelvic cavity, which is thought to increase risk for ectopic pregnancy. A French study reported the risk of ectopic in women with a history of PID to be 3.4 times higher than in women who had never experienced PID;
• History of sexually transmitted infection (particularly chlamydia and gonorrhoea): Women with a history of STI are more likely to develop an ectopic pregnancy and a history of multiple STIs may increase the risk even further. STIs are associated with pelvic infection, post inflammatory scarring and distortion of normal reproductive anatomy which appear to cause the increased risk of ectopic pregnancy;
• Many lifetime sexual partners 
• Age: The risk of ectopic pregnancy increases with age. Women who are more than 40 years of age are 2.9 times more likely to develop an ectopic pregnancy if they become pregnant, than women who are 25-29 years;
• History of infertility: Women who have been infertile in the past are more likely to develop an ectopic pregnancy than those who have not been infertile. The risk of developing an ectopic pregnancy increases with the number of years of infertility. Women who have been infertile for two or more years are 2.7 times more likely, women who have been infertile for 1-2 years are 2.6 times more likely, and those who have been infertile for less than one year 2.1 times more likely to develop an ectopic pregnancy than women who have never been infertile;
• History of using assisted reproduction techniques: Ectopic pregnancies account for some 4% of all pregnancies in women who have used assisted reproductive techniques, compared to estimated 2% of pregnancies in total;
• History of, or current, intrauterine contraceptive device use: Women who have previously used an intrauterine device are 1.3 times more likely to develop an ectopic pregnancy than those who have not. When a woman who is using an intrauterine device becomes pregnant (a rare event), there is a high chance the pregnancy is ectopic;
• History of tubal surgery: Women who have undergone surgery involving the fallopian tubes are 4 times more likely to have an ectopic pregnancy than those who have not had tubal surgery;
• Sterilisation: Pregnancy in general is uncommon following sterilisation, however when it does occur, pregnancy is usually ectopic. Women sterilised using the bipolar coagulation technique had the highest rate of ectopic pregnancy following sterilisation (17.3 events per 1000 sterilisations), while women sterilised by postpartum partial salpingectomy, had the lowest rate of ectopic pregnancy (1.5 per 1000). Women under 30 years of age at the time of sterilisation had a higher risk of ectopic pregnancy than those who were aged 30 or more when sterilised.

The following factor haa a protective effect in relation to ectopic pregnancy:

• History of oral contraceptive use: Women who have used oral contraceptives in the past are less likely to develop an ectopic pregnancy than those who have never used oral contraceptives.

Progression

Following fertilisation of the egg, the embryo of an ectopic pregnancy implants outside the uterus and grows. In some cases the pregnancy will naturally resolve (i.e. the woman will have a miscarriage and the embryo will be expelled from the body) however when spontaneous abortion (i.e. miscarriage) does not occur, the embryo will continue to grow. If left untreated the embryo can grow too large to be accommodated by the surrounding organs. In this case the embryo can cause a rupture and considerably damage the reproductive organs. In very serious cases, ectopic pregnancy also poses a threat to the pregnant woman’s life.

Symptoms

Women with an ectopic pregnancy will appear pregnant (i.e. when a pregnancy test is conducted on a woman with ectopic pregnancy, the result will be positive). The most common symptoms of ectopic pregnancy are lower abdominal pain (reported by over 90% of women with ectopic pregnancy) and abnormal menstrual bleeding (reported by over 80% of women). If left untreated, the consequences of ectopic pregnancy include damage to the reproductive organs, reduced fertility and in the most severe cases, death.

Clinical Examination

If a doctor suspects a patient may have an ectopic pregnancy, a pregnancy test will usually be performed and questions about the woman’s sexual and reproductive history will be asked. The questions will probably focus on the risk factors for ectopic pregnancy (e.g. history of miscarriage, STI). A doctor may also wish to perform a pelvic examination to assess the tenderness of the pelvic area, in order to assess whether further screening for ectopic pregnancy is required.

How is it Diagnosed

If a pregnancy test, questioning and physical examination of the pelvis indicate the possibility of ectopic pregnancy, further tests need to be conducted, in most cases a transvaginal ultrasound. Depending on the equipment and specialists available, this may require the patient be referred to a hospital or specialist.

A transvaginal ultrasound is an ultrasound test which focuses on the vaginal area. When assessing a normal pregnancy occurring in the uterus, transabdominal ultrasound is used. The ultrasound test enables a health specialist to look inside the woman and see whether there are any abnormalities (e.g. a growing mass in the fallopian tubes) which may be the embryo of an ectopic pregnancy.

Ultrasound is often used in conjunction with measurements of the level of a hormone called human chorionic gonadotrophin. It is the same hormone measured in a standard urine pregnancy test and can increase the accuracy of diagnosis using ultrasound.

In rare cases, either when an ectopic pregnancy cannot be identified using ultrasound, or when a woman with suspected ectopic pregnancy presents in a critical state (e.g. collapsed with suspected rupture of the ectopic pregnancy) laparoscopy may be performed to diagnose the ectopic pregnancy. However in most case laparoscopy is used only in the treatment of ectopic pregnancy.

Prognosis

Ectopic pregnancy is potentially life threatening if left untreated, however a proportion of cases will resolve naturally and can be managed using expectant techniques (i.e. a “wait and see” approach, in which the woman is monitored for signs that the pregnancy has resolved). However in most cases ectopic pregnancies require either medical or surgical intervention. Both techniques are effective in removing the abnormal embryo and the majority of women are able to fall pregnant again after either medical or surgical treatments.

Treatment

Ectopic pregnancy threatens the life and fertility of a woman if left untreated. A fertilised egg which implants outside the uterus (i.e. an ectopic pregnancy) is not a viable foetus which can develop into a baby. However some people believe that life begins at conception and for these people treatment of an ectopic pregnancy can present a moral dilemma. It is therefore important for patients faced with the choice to treat or not to treat an ectopic pregnancy to bear in mind that the embryo of an ectopic pregnancy cannot develop into a normal baby and will eventually die of its own accord.

When treatment is agreed upon, there are a range of treatment options. Surgery has traditionally been the only method of treating ectopic pregnancy and remains the most common form of treatment. However medical treatment (i.e. the prescription and administration of medication to induce termination of the ectopic pregnancy) and expectant monitoring of the ectopic pregnancy (i.e. waiting to see if spontaneous abortion occurs) are becoming increasingly popular. Choice of treatment will depend on the gestation of the ectopic pregnancy, health of the pregnant woman, her personal wishes and availability of ultrasonographic and laparoscopic equipment and expertise.

Expectant monitoring

Expectant monitoring is appropriate for managing select cases of ectopic pregnancy. If this is the preferred method of treatment, a health practitioner will probably measure the pregnant woman’s human chorionic gonadotrophin concentrations to assess whether expectant management is appropriate. Where human chorionic gonadotrophin levels are relatively low, expectant management is successful in treating 88% of cases. However where expectant management fails, medical and surgical treatment is necessary.

Medical treatment

Administration of a single intramuscular injection of the drug Methotrexate, is considered the best medical treatment for ectopic pregnancy. It is suitable for the treatment of uncomplicated ectopic pregnancies, diagnosed in the first trimester. A single injection is effective in removing ectopic pregnancies in most cases. However in some cases a repeat injection or surgical intervention is required. It is normal for the doctor to monitor human chorionic gonadotrophin levels following administration of the medication, to assess whether or not it has worked.

Methotrexate can also be injected straight into the ectopic gestational sac, however this technique requires laparoscopy and has a higher failure rate than intra muscular injection.

Surgical treatment

Surgery can be conservative or radical depending on the length of gestation at diagnosis, presence or absence of rupture and health of the pregnant woman. Common surgical treatments are:

• Salpingostomy: is a conservative surgical treatment for ectopic pregnancy which involves the removal of the embryoalone.
• Salpingectomy:is a radical surgical treatment for ectopic pregnancy which involves the removal of the embryo and the tube in which is occurs. It is recommended in cases where the fallopian tube is extensively diseased or damaged and risk of ectopic pregnancy recurring is high.

Either type of surgery can be performed via laparoscopy or laparotomy. Laparoscopic surgery is less costly and is associated with shorter hospital stays and recovery times but there is a higher rate of recurring problems in the long term following laparoscopic surgery.

Treatment for the psychological side effects

Ectopic pregnancy can be distressing and often results in feelings of grief, loss and depression. Patients may require counseling and/or support group participation to help them cope with the psychological difficulties of ectopic pregnancy.

References

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