Ectopic pregnancy

Summary

• An ectopic pregnancy is one in which the fertilised egg is implanted outside the womb
• The most common site for this is within the fallopian (uterine) tubes
• The main risk factor for ectopic pregnancy is previous infection of the tubes
• Left untreated, ectopic pregnancy can cause a life-threatening condition and can be fatal due to intra-abdominal haemorrhage
• The treatment is surgical removal of the embryo alone or with the damaged tube

Definition

An ectopic pregnancy is one in which the fertilised egg is implanted outside the womb (uterus) – usually in the fallopian tube, sometimes in the ovary or the pelvic or abdominal cavity, and very rarely in the cervix (neck of the womb).

The most common site of ectopic implantation is somewhere in a fallopian tube.

Who is at risk?

The incidence of ectopic pregnancies varies between 13 to 20 per 1 000 pregnancies. This may be modified by different cultural groups depending on the prevalence of sexually transmitted diseases (STDs).

Micro-organisms which are sexually transmitted, gain access to the fallopian tubes and cause infection, called salpingitis and PID (Pelvic Inflammatory Disease). This leads to damage of the tubal mucosa with scarring and incomplete obstruction of the tubes. The ascending sperms may manage to pass through. However, the fertilised egg while growing and undergoing cell division (blastocyst), may become trapped on route to the uterus.

Risk factors

• Previous tubal disease such as sexually transmitted diseases and PID
• Previous ectopic pregnancy – this increases the risk by 10 to 25%
• Induced abortion (“termination of pregnancy”) with subsequent infection
• Tuberculosis of the upper genital tract (usually spread through the blood from a primary site, e.g. lungs)
• History of tubal surgery
  • for infertility
  • conservative surgery for a previous ectopic pregnancy
  • reversal of tubal ligation

Intrauterine contraceptive devices do not prevent ectopic pregnancy.

Symptoms and signs

The first symptoms are usually spotting and cramping pain which begin shortly after the first missed period. The symptoms are similar to those of a threatened miscarriage. This bleeding comes from the endometrium (lining of the womb) due to a drop in pregnancy hormone level.

Furthermore, there is bleeding from the affected fallopian tube. This bleeding may be gradual and causes pain, while rapid bleeding can cause a dramatic drop in blood pressure and shock.

During the gynaecological examination, the doctor will feel that the uterus is softer and possibly slightly larger than normal, but smaller than for the anticipated duration of the pregnancy. The cervix is often tender when moved, and there may be a palpable mass in the area of the left or right fallopian tube.

The pregnancy test in the urine or in the blood may be positive. An ultrasound examination will show an empty uterus often with a complex cystic mass at the affected tubal side and sometimes free fluid behind the uterus. This strongly suggests an ectopic pregnancy.

In doubtful cases serial levels of beta-HCG are helpful. In a normal pregnancy, the levels of beta-HCG double every 48 hours. In an ectopic pregnancy, the levels of beta-HCG may be lower than expected for gestation time and do not show the normal doubling time.

At about six to eight weeks of pregnancy, marked sudden lower abdominal pain may occur, which can be followed by collapse of the circulatory system leading to shock. Often this suggests that the embryo with its gestational sac and developing placental tissue has expanded the fallopian tube to such an extent that the tube has ruptured and that there is bleeding into the abdomen. An alternative to rupture is the expulsion of the embryo at the tubal end, which can occur if the implantation has been close to the opening of the tube. This is called a tubal abortion and is usually associated with less internal bleeding.

Treatment

If a ruptured ectopic pregnancy is diagnosed, the patient – if necessary - is resuscitated, her circulation is stabilised, blood is ordered for transfusion and the patient is taken to the operating theatre for surgery. This entails opening the abdomen and removing the embryo/fetus with or without the tube, depending on the degree of tissue damage.

In a woman who still wants to have children, every effort is made by conservative surgery to save the tube for future conception. If she does not want to have any more children, she may be counselled for a sterilisation before entering the operating theatre. The affected tube is removed and she has the option to have the tube on the other side ligated (tubal sterilisation). This would have the advantage to save her the increased risk of a repeat ectopic pregnancy since the initial damage, which has caused the ectopic, is usually bilateral.

Even if an ectopic pregnancy is diagnosed before rupture, the treatment is still surgery, now increasingly by laparoscopy. Under general anaesthesia, a laparoscope linked to an external video camera and monitor system, is inserted through a small opening into the abdominal cavity. Through additional “portholes” in the abdominal wall, long but tiny instruments (scissors, electrocoagulator) are manoeuvred while watching the video monitor.

The tube is opened, the embryo and its surrounding tissues are removed, and any bleeding is staunched by cauterisation or suture. If necessary, the entire affected tube can be removed laparoscopically. The advantage of this type of endoscopic surgery is that the patient recovers quicker than with a conventional abdominal incision and that she can be discharged earlier from hospital.

If an intact ectopic pregnancy is diagnosed very early, for example following infertility treatment by assisted reproduction (IVF, GIFT), certain medication can be administered to stop the pregnancy from growing, thus avoiding surgery. However, this requires meticulous monitoring of the patient with repeated ultrasound and blood examinations.

Outcome

Fortunately, the death rate for ectopic pregnancy is falling, but less rapidly than maternal deaths in general. Left untreated, ectopic pregnancy is often fatal to the patient.

When to call the doctor

• If you have a positive pregnancy test and you experience spotting and cramping pain soon after the diagnosis of pregnancy. This may be a threatening miscarriage but could also point to an ectopic pregnancy.
• If your pregnancy is more advanced and you experience sudden severe abdominal pain, followed by weakness.
• If you experience vaginal bleeding and pain at any stage of your pregnancy

Reviewed by Dr Herkie Sandenbergh, Dept of Obstetrics & Gynaecology, University of Stellenbosch