Before we talk about ectopic pregnancy, let’s talk about a woman’s reproductive system and how normal pregnancy takes place.
Image credit: CDC, Mysid, Public domain, via Wikimedia Commons
As shown in the image above, a woman's reproductive system includes the uterus, two ovaries, two fallopian tubes, and the vagina. The fallopian tubes are narrow tubes that link the ovaries and uterus. Remember them, because they’re an important topic for this article.
In a normal pregnancy, when an egg and sperm join, they rapidly begin to develop new cells. This group of cells, called the embryo, normally implants on the inner lining of the uterus (known as endometrium). Once implanted, the embryo continues to grow and also forms the placenta, the organ that provides a blood supply for the developing embryo. The embryo grows and continues to develop into foetus, i.e. a baby in the woman’s womb.
But what if the embryo does not get implanted on the inner lining of the uterus but rather on the other parts of the woman’s reproductive system? This is known as ectopic pregnancy, i.e. pregnancy that happens outside the uterus, and it is a dangerous medical emergency.
Image credit: BruceBlaus, CC BY-SA 4.0 , via Wikimedia Commons
Why is ectopic pregnancy dangerous?
Remember we mentioned fallopian tubes earlier? Well, 98% of ectopic pregnancy happens at the fallopian tubes. Very rarely, the developing embryo will attach to another site, such as the cervix or an ovary.
Ectopic pregnancy is dangerous because not only the embryos cannot develop normally, but it can cause rupture of the organ on which they are implanted, typically the fallopian tube. As a result, the woman may experience severe internal bleeding, shock and even death if treatment is not given on time. Fortunately, the ability to diagnose, monitor, and treat ectopic pregnancy reduces the risk of these life-threatening complications.
What increases the risk of ectopic pregnancy?
Here are some factors that may increase a woman’s risk of developing ectopic pregnancy:
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Abnormalities of fallopian tubes, which can be a result of previous infection, surgery, tumors or malformations since birth.
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Infertility - This could be because women with abnormal fallopian tubes are also more likely to be infertile.
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Having multiple sexual partners - Having more than one sexual partner increases the risk of pelvic infection, which in turns increase risk of ectopic pregnancy
If you have any of these risk factors and are worried about ectopic pregnancy, consult a doctor.
How do you know if you might have an ectopic pregnancy?
The most common signs and symptoms related to ectopic pregnancy is vaginal bleeding (which may be minimal) during the first trimester and/or abdominal pain.
However, some women have no symptoms until the fallopian tube ruptures. Following rupture of the tube, the woman may experience severe pain and some may have vaginal bleeding. Lightheadedness or dizziness may occur first, followed by a drop in blood pressure, fainting, and shock.
Sometimes, the embryo is expelled by the fallopian tube before rupture occurs. This is called a "tubal abortion." Women who have tubal abortion can develop either severe bleeding, requiring surgery; or minimal bleeding that does not require treatment. Nevertheless, ectopic pregnancy is a medical emergency and requires immediate medical attention.
Treatment for ectopic pregnancy
Medication - methotrexate
Approximately one-third of women with ectopic pregnancies can be treated with a medication called methotrexate, which stops the growth of the embryo. Methotrexate is typically taken as a pill in other medical conditions; however in the case of ectopic pregnancy, it is commonly given as intramuscular injection for quicker effect, at an intermediate dose (1 mg/kg).
Methotrexate works by preventing folic acid from working. As a result, it inhibits DNA synthesis and cell reproduction. However, methotrexate can be toxic to even normal cells. Hence, in some cases, the doctor may also prescribe a medication called leucovorin (a.k.a folinic acid), which serves as a protection against methotrexate for the normal cells.
During methotrexate therapy for ectopic pregnancy, you should practise a few precautions:
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The doctor would monitor your serum beta-human chorionic gonadotropin (hCG) to evaluate the effect of therapy. Avoid vaginal intercourse and new conception until your hCG is undetectable.
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Avoid taking any dietary supplement containing folic acid so that it does not reduce the effect of methotrexate.
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Avoid taking nonsteroidal anti-inflammatory drugs (NSAIDs) throughout the therapy. This is because NSAIDs may interact with methotrexate, reduce the excretion of methotrexate from the kidney and increase risk of toxicity.
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It’s common for you to experience abdominal pain of short duration (1-2 days) at 6 to 7 days after receiving methotrexate. The pain can be controlled by taking paracetamol. However, if the pain is severe, do consult your doctor immediately.
Surgery
If the fallopian tube has already ruptured, or the woman is unfit for methotrexate therapy, a surgery is warranted. Surgery may be performed using a laparoscopic approach or through an abdominal incision. In laparoscopy, instruments are inserted into the abdomen through a few small incisions. These instruments are used to see and remove the ectopic pregnancy and control bleeding. Compared with abdominal surgery, laparoscopic surgery causes less pain and allows for a faster recovery.
Will a prior ectopic pregnancy affect my ability to conceive in the future?
Methotrexate therapy is known to cause abortion and fetal malformations if taken during pregnancy. If you have taken methotrexate for ectopic pregnancy, it is advisable to not conceive for three months following the discontinuation of methotrexate to allow a washout period.
On the other hand, it is possible to have a successful pregnancy following an ectopic pregnancy. There are many factors, however, that can affect a pregnancy outcome. Consult a specialist if you wish to conceive.
A word from Doc2Us
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References
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UpToDate - Patient education: Ectopic (tubal) pregnancy (Beyond the Basics)
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UpToDate - Ectopic pregnancy: Epidemiology, risk factors, and anatomic sites
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UpToDate - Ectopic pregnancy: Clinical manifestations and diagnosis
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UpToDate - Ectopic pregnancy: Methotrexate therapy
Cover image credit: Image by StockSnap from Pixabay
