Written by Dr.M.D.Mazumdar, MD
An ectopic pregnancy is one in which the fertilized ovum implants and develops outside the uterine cavity.
The normal position for a fertilized ovum to implant and grow is inside the uterine cavity. (see How Pregnancy Occurs).
In a normal pregnancy, the growing fetus can be carried to full term inside the uterus since the muscles of the uterus are capable of increasing in size and number.
But, if the embryo is implanted in or on an organ that cannot increase in size, like the fallopian tubes or the ovaries, it fails to develop properly.
The growing fetus can cause rupture of the tubes, leading to severe bleeding.
The fertilized ovum can be implanted at various sites during its passage through the tubes to the uterus. The commonest site is in the fallopian tubes.
Fallopian Tubes: Tubal pregnancy comprises about 95% of all ectopic pregnancies.
Abdominal Pregnancy: Ectopic pregnancy can sometimes occur in the abdominal cavity. It is very rare. It is usually a result of the embryo being aborted intact from the tube.
Occasionally, the tube can rupture with minimal bleeding, gently pushing the embryo into the abdominal cavity. The embryo develops in this ectopic site by attaching its placenta to the bowels, omentum, broad ligament or any other abdominal organ. The broad ligament is the most common site of abdominal ectopic pregnancy. But it is rare for the fetus to develop completely to term in this site. Death usually occurs at around 20- 28 weeks of pregnancy.
Ovaries: Ectopic pregnancy can occur very rarely on the surface of the ovaries.
The fertilized ovum takes about 7 - 10 days to reach the uterus from its site of fertilization in the tubes (see How pregnancy occurs). If the movement of the fertilized ovum from the tubes to the uterus is slowed down due to any reason, the ovum will implant at the region that it reaches on the 7-10th day. So the causes for ectopic pregnancy are the same as the causes that decrease the movement of the ovum towards the uterus.
Causes of infections may be previous abortions, appendicitis, pelvic inflammatory diseases, intrauterine contraceptive devices like loops, or any surgery in the pelvis. Previous pelvic infection, especially by the sexually transmitted disease, Chlamydia, is the commonest cause of ectopic pregnancy.
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The embryo can grow up to a maximum of 8 weeks in the tubes. At 8 weeks, and usually by 6th week, the tube ruptures as it cannot support the developing embryo any more.
The signs and symptoms of ectopic pregnancy depend on whether the patient is examined before or after the tubes have ruptured.
A. Before Rupture of the Tubes:
Signs and Symptoms of Very Early Pregnancy: The patient usually has all the signs and symptoms of very early pregnancy:
- Missed Periods: She will complain of missed periods of a few weeks duration- usually less than 6 weeks and definitely not more than 8 weeks of pregnancy.
- Nausea and vomiting which is usually mild.
- Sore breasts.
- Loss of appetite.
- Frequency of passing urine.
Mild vaginal bleeding or brown stained discharge: She may come with complains of mild bleeding in early pregnancy or even only brown stained discharge. She may confuse this bleeding with implantation bleeding or the start of an abortion.
She may have pain in her lower abdomen. The pain is usually spasmodic in nature with occasional cramps. Sometimes it may be so mild as to cause only a discomfort or mild pain while walking or standing up from a sitting down position. Sometimes however there may be an acute stabbing pain that causes the patient to double up.
Unruptured ectopic pregnancy is diagnosed by:
The severe bleeding can cause the patient to go into shock. There is severe pallor, hands and feet feel cold and clammy, blood pressure is low or unrecordable , pulse is thin and thready as well as other signs and symptoms of shock. Death can occur very quickly, if treatment is not immediate.
Methotrexate is most likely to work if the HCG level is low - less than 5,000, and/or when the embryo has no heart activity.
The dead embryo gradually degenerates and is reabsorbed into the body.
Methotrexate can also be directly injected into the embryo during laparoscopy. The embryo need not be taken out as it will die and degenerate. This cuts down considerably on the time taken for operation.
Immediate surgery should be done to stem the blood flow, rather than to remove the embryo. As soon as the operation is started and the abdomen is opened, the ruptured edges of the tube is identified, and the bleeding blood vessels tied. This stops the bleeding immediately. It is only then that the embryo is searched for and taken out.
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