The EPT

Not all ectopic pregnancies are tubal. There are other parts of the body which might be affected by ectopic pregnancy.

Sites and frequencies of ectopic pregnancy

These are the most common sites:

• Ampullary, 80%;
• Isthmic, 12%;
• Fimbrial, 5%;
• Cornual/Interstitial, 2%.

Other sites ectopic pregnancy can be located are:

• In the abdomen. Abdominal, 1.4%;
• In or on the ovary. Ovarian, 0.2%;
• On the Cervix. Cervical, 0.2%.

Interstitial pregnancy 2%

A cornual pregnancy or interstitial pregnancy is a rare type of ectopic pregnancy which occurs when the fertilised egg implants in that part of the fallopian tube buried deep in the wall of the uterus. Pregnancies of this kind are difficult to diagnose as they appear to be in the uterus on scan. They are particularly dangerous as they can progress further and tend to rupture later, having the potential to damage both the wall of the uterus and the fallopian tube. If diagnosed early enough, doctors will often select medical treatment with methotrexate if the patient is a suitable candidate for this. Surgery for an interstitial pregnancy, can involve surgery to the actual uterine wall and this could result in the uterus being less strong than it would have been before surgery. However, it is possible to have successful uterine pregnancies after an interstitial pregnancy. Your doctor will assess you carefully and consider the need for an elective caesarean section to deliver any subsequent pregnancy, and the preferred method of delivery will depend on the extent of the surgery necessary on the uterine wall to resolve the ectopic pregnancy.

In the abdomen 1.4%

Abdominal pregnancies, in most instances, are thought to have begun in the fallopian tube and then separated from the wall of the fallopian tube, floating into the abdominal cavity to then reattach to one of the structures in the abdomen. The pregnancy can progress and may go undetected until many weeks in to the pregnancy. There are some accounts of abdominal pregnancies surviving to be delivered with an abdominal operation but these are incredibly rare.

In or on the ovary 0.2%

The ovary is a highly vascular structure. An ectopic pregnancy located on or in the ovary will usually require surgery involving either the partial or complete removal of the ovary. If the ovary is only partially removed, it may recover and continue to produce eggs as before. However, even if it does not produce eggs any longer or is removed completely, your other ovary is perfectly capable of producing an egg every cycle, enabling the woman to conceive naturally in the future.

In the cervix 0.2%

Cervical pregnancies are one of the rarest forms of ectopic gestations. The incidence of cervical ectopic pregnancies ranges between 1 in 1,000 to 95,000 gestations. Prior surgical trauma, including dilatation and curettage of the cervix, has been identified as one of the leading risk factors

Cervical ectopic pregnancies are of special concern because of the risk of life-threatening haemorrhage. The cervix is highly vascular and should the pregnancy cause a rupture, blood transfusions are usually essential. An emergency hysterectomy has previously been the only option. However, conservative management of a stable, cervical ectopic pregnancy using methotrexate or potassium chloride is now the treatment of choice and the use of these treatments preserves the woman’s fertility.

Heterotopic Pregnancy

(incidence uncertain, thought to be between 1.25 and 6.25:10,000)

Heterotopic pregnancy is the term used to describe a condition where there is the co-existence of an intrauterine pregnancy with an ectopic pregnancy. Although it is rare, it is possible for one embryo to implant in the uterus and another elsewhere (in the tube for example). This occurs in a very small number of ectopic pregnancies (less than 1-2% of ectopic pregnancies).

In heterotopic pregnancy it is possible for the co-existing intrauterine twin to survive, which happens in around 30% of diagnosed cases of heterotopic pregnancy, despite the woman being treated surgically for the condition.

In the scar of a caesarean section

(incidence is uncertain, thought to be around 1:18,000)

Research indicates that this kind of ectopic pregnancy appears to be increasing, probably due to the impact of elective caesarean section delivery which was much more common 10 years ago than today.

The egg implants in the scar where the uterus is not strong enough to sustain the pregnancy without rupturing. A ruptured uterus is life-threatening. Treatment is usually with laparoscopy, using  interventions such as methotrexate or surgery but thanks to modern techniques, hysterectomy can usually be avoided.