Ectopic pregnancy is a condition in which the fertilised egg (embryo) is implanted outside the uterine cavity. Its occurrence varies in different countries but it is estimated to occur in about one in 100 pregnancies.
Unseen: About 50% of ectopic pregnancies do not exhibit any specific symptoms.
About 95% of ectopic pregnancies occur in the fallopian tubes. It can also occur in other sites like the ovary, cervix or abdominal cavity.
An ectopic pregnancy is life-threatening as it can rupture, causing bleeding into the abdominal cavity. The earlier an ectopic pregnancy is treated, the better the outcome. Delay will lead to further damage to the fallopian tubes or other sites and if left untreated, the blood loss can result in death.
Risk factors
When an egg is released by the ovary, it travels along the fallopian tube where it is fertilised by the sperm. The lining of the fallopian tubes contain hair-like structures, called cilia, which push the embryo along into the uterine cavity where it gets embedded. If there is damage to the fallopian tubes, the cilia may be unable to perform its function, resulting in the embryo embedding in the fallopian tube itself.
These factors increase the likelihood of ectopic pregnancy:
Pelvic inflammatory disease (PID) in which the ovaries, fallopian tubes and uterus have been or are infected.
Intra-uterine contraceptive device especially when it is associated with PID.
Previous surgery on the fallopian tubes like sterilisation, its reversal or other surgery.
Previous abdominal surgery like caesarean section and fibroid removal (myomectomy).
In-vitro fertilisation (IVF). Although the embryo is placed inside the uterine cavity, it may still attach itself to the fallopian tube.
Previous ectopic pregnancy. The risk of an ectopic pregnancy increases from 1% to 10% after an ectopic pregnancy has occurred.
The risk in women aged 44 years or more is increased from 1% to 8%.
It should be noted that these risk factors are not present in many women who have an ectopic pregnancy.
Diagnosis
About 50% of women with an ectopic pregnancy have no specific symptoms apart from those associated with pregnancies such as missed period, nausea and sore breasts.
The symptoms include:
Vaginal bleeding that differs from that of the normal period in that it is lighter or darker.
Abdominal pain which is usually on one side. The pain may be severe and persistent.
Shoulder tip pain which is due to the blood in the abdominal cavity irritating the diaphragm, which has the same nerve supply as the shoulders.
Pain on passing motion or urine.
The diagnosis is made by clinical examination in most instances. A transvaginal ultrasound is helpful in diagnosis. This involves inserting the ultrasound probe into the vagina to visualise the uterus and its surroundings.
Sometimes, the diagnosis is made at laparoscopy, which is an operative procedure that involves direct visualisation of the pelvic organs through small incisions in the abdomen. This procedure is useful especially when there are no specific symptoms. After making the diagnosis at laparoscopy, a decision will be made on the mode of management.
Management
The management is influenced considerably by whether the diagnosis is made before the ectopic pregnancy has ruptured or not. The gynaecologist will discuss the various treatment options with the patient.
Surgery to remove the embryo from the abdominal cavity is the most common treatment. If there is no indication of shock, the laparoscopy approach is usually preferred. If there are changes indicating shock, a laparotomy is preferred, in which the larger incision will facilitate an expeditious stopping of the bleeding.
The part of the fallopian tube in which the embryo is located (salpingectomy) is removed or the embryo is removed through an opening in the tube (salpingotomy). If the other tube appears normal, there is no evidence that a salpingotomy is preferable to a salpingectomy. If the other tube appears diseased and there is a desire for future fertility, a salpingotomy is preferred, as a salpingectomy would mean that IVF or other assisted reproduction would be required for the next pregnancy.
Medical treatment can be provided if the ectopic pregnancy is diagnosed early. Methotrexate may be prescribed to stop the pregnancy from continuing. The women who are most suited for methotrexate treatment are those with minimal or no symptoms and a serum human chorionic gonadotrophin (hCG) below 3,000 IU/l.
The side effects of methotrexate include nausea, vomiting, sore mouth and sore eyes. About 75% of those given methotrexate will experience abdominal pain which may be difficult to differentiate from that of tubal rupture.
Expectant treatment (“Wait and see”) refers to situations where there are minimal symptoms and the pregnancy’s location is unknown.
This situation occurs when the hCG is less than 1,000 IU/l and no pregnancy, whether inside or outside the uterine cavity, is visible on transvaginal ultrasound.
Up to 60% of such pregnancies resolve spontaneously without any treatment. Regular examinations and blood tests are mandatory with expectant management, until the hCG levels are below 20 IU/l.
Surgery will have to be resorted to at any time during medical or expectant treatment should the clinical situation warrants it. Anti-D immunoglobulin will be given to all rhesus negative women with suspected or confirmed ectopic pregnancy.
Prevention
Ectopic pregnancies cannot be prevented. However, one of its major risk factors, pelvic inflammatory disease (PID), can be prevented. The primary cause of PID is sexually transmitted infections (STI), which is preventable. Regular use of the condom can prevent STIs. Knowing one’s sexual partner and having one sexual partner can also prevent STIs. Regular sexual health checks are helpful particularly if one suspects one’s sexual partner has STI and/or PID.
Dr Milton Lum is member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with.
Source: The Star,16 Sept 09.
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