Ectopic pregnancy is the name given to every embryo implantation that occur outside the uterine cavity, that is to say, when the fertilised egg does not reach the mother’s womb after travelling down the Fallopian tube but implants into a different tissue. The mother’s womb is the right place for embryo implantation and development.
Most cases of ectopic pregnancy (95%) occur in the Fallopian tube, so-called tubal pregnancies. There are less frequent places such as the ovary, the abdominal cavity, or the cervical canal.
This type of pregnancy is the most frequent cause for maternal mortality during the first quarter of gestation. Its mortality rate is 1.8 deaths per every 1,000 ectopic pregnancies. Ectopic pregnancy occurs at a rate of 1 case per 100 pregnant women, that is to say, 1%.
Over the last 20 years, frequency of ectopic pregnancies has increased due to new clinical methods. New risk factors such as the development of assisted reproductive treatments may also be the cause for this rising.
Causes of ectopic pregnancy
Any alteration blocking or slowing the egg’s movement through the Fallopian tubes increases the risk of developing an ectopic pregnancy:
- Birth defect of the Fallopian tubes
- Healing after a ruptured appendix
- Previous ectopic pregnancies
- Healing after surgery
For those cases in which the exact cause is unknown, it is thought that hormones could play a major role.
Symptoms of ectopic pregnancy
Women with an ectopic pregnancy may not feel any symptom during early pregnancy; however, as the embryo develops, the following symptoms are likely to appear: strong abdominal pain, vaginal bleeding, shoulder pain, nausea, etc.
These symptoms may worsen if the embryo causes the Fallopian tube to burst, provoking an internal bleeding which may lead to shock or even to the death of the pregnant woman.
For this reason, performing a quick diagnosis is important to prevent more severe problems and to avoid using very aggressive treatments.
Diagnosis of ectopic pregnancy
The most important methods for the diagnosis of an ectopic pregnancy are: determination of the beta-hCG hormone and transvaginal ultrasound.
An advantage of assisted reproductive treatments when it comes to diagnosing an ectopic pregnancy is that it allows a quick diagnosis. This is possible because the first method to detect a potential pregnancy consists of performing a blood test in order to detect the presence of the β-hCG hormone. This blood test should be done only 15 days after the artificial insemination –in case you undergo an AI– or after the embryo transfer –in case you undergo an in vitro fertilisation.
If the result of the blood test is positive, pregnancy will be confirmed 2 weeks later with a transvaginal ultrasound, which will allow us to see the presence of an embryonic sac.
In case no sac is seen on the uterus but we have a positive β-hCG, consideration should be given to the possibility of having an ectopic pregnancy. If so, it should be confirmed by means of another β-hCG blood test or biomarkers such as progesterone, placental protein 14, Ca-125, or creatine phosphokinase (CPK), among others.
Treatment of ectopic pregnancy
In several occasions, the ectopic embryo does not continue its development because an early abortion occurs, generally a tubal abortion. Otherwise, it can be solved with surgery or medical treatments such as chemotherapy drugs containing methotrexate.
The choice between these two types of treatments is valuated according to the diagnostic tests and the symptoms of the patient, who should be given the appropriate information about the advantages and disadvantages of each treatment.
The psychological impact which an early abortion may cause to the woman and her partner should also be taken into account.