Ectopic pregnancies refer to any pregnancy that develops outside the endometrial cavity.
They affect approximately 1 in 90 pregnancies in the UK, translating to around 11,000 cases a year.
The key to safe management and minimising maternal mortality is prompt recognition. When missed or late presenting, ectopic pregnancies can lead to serious and potentially fatal complications.
Two national guidelines are available covering the diagnosis and management of ectopic pregnancy:
The vast majority, 97%, of ectopic pregnancies develop in the fallopian tube.
The fallopian tubes are by far the most common site of ectopic pregnancy. Any pathology (infection, adhesions, iatrogenic injury) that damages the tubes will therefore lead to an increased risk. The ampulla of the tube is the most common site followed by the isthmus, but they may implant anywhere along the length of the structure.
Ectopic pregnancies affecting the interstitium of the fallopian tube (termed interstitial pregnancies) are relatively rare, thought to account for around 2-6% of cases. They are harder to diagnose sonographically and are thought to present later due to the wider interstitial portion of the fallopian tube being able to accommodate larger pregnancies. Their location and larger size at presentation results in more catastrophic bleeding in the event of a rupture. Combined with diagnostic challenges the condition has a higher mortality than ectopics occurring elsewhere in the fallopian tube. In addition to transvaginal US, diagnosis may be aided by MRI or diagnostic laparoscopy.
The other 2-3% implant elsewhere, sites include the ovary, cervix, peritoneum and C-section scars.
A number of factors increase the risk of ectopic pregnancy - however the majority of women have no identifiable risk factor.
Features may be subtle and non specific, patients with child-bearing potential must be offered a pregnancy test when presenting to hospital with an acute complaint.
Patients may or may not be aware that they are pregnant. Symptoms of tubal ectopics typically develop 6-8 weeks after the last normal period. Presentations range from mild abdominal upset with or without vaginal bleeding to hypovolaemic shock secondary to a ruptured tubal ectopic with significant blood loss. The features described here are predominantly for tubal ectopics though there may be significant cross-over with ectopics in other sites.
A ruptured ectopic pregnancy is a gynaecological emergency. There can be significant intra-abdominal bleeding leading to syncope and haemodynamic instability. Vomiting, diarrhoea and shoulder tip pain may be present. Vaginal bleeding may be present but often misleads regarding the degree of blood loss as much will be intra-abdominal.
Trans-vaginal USS is the investigation of choice in the diagnosis of ectopic pregnancy.
Trans-vaginal USS: the standard investigation. It provides good visualisation and identifies the majority of tubal ectopic pregnancies on first assessment. A minority of cases won’t be identified and are termed ‘pregnancy of unknown location (PUL)’. This may be due to the location or how early in the process someone is scanned.
Trans-abdominal USS: should generally only be used where the patient declines the transvaginal approach. You must explain the reduced sensitivity and specificity of this approach.
MRI: may be used as a second-line investigation and can be of particular use in cervical scar or interstitial pregnancies.
Serum beta-human chorionic gonadotrophin may be used to help guide management of ectopic pregnancy.
Serum B-HCG should be measured in any patient with a diagnosis of ectopic pregnancy. It gives an indication as to the chance of success of medical management
Care must be taken when interpreting serum B-HCG. A single serum B-HCG cannot be used to predict an ectopic pregnancy. A single low serum B-HCG does not exclude ectopic pregnancy, in practice many may have low levels.
The exact use of serum B-HCG has subtle differences depending on the location - this is beyond the scope of these notes. Refer to the RCOG/AEPU Joint Guidelines for more detail.
Management of ectopic pregnancy falls into three main types; expectant, pharmacological and surgical.
Here we discuss the management of tubal ectopics (excluding interstitial pregnancies). Though other locations may follow similar management schemes, the nuances are beyond the scope of this note.
This may be considered in carefully selected patients. They should be well, with only minor pain and low or declining B-hCG. Patients must also be willing and able to attend follow-up.
NICE guidelines 126 advise the following women are offered expectant management:
They also state it may be considered in women with serum B-hCG levels above 1,000 IU/L and below 1,500 IU/L.
Serum B-hCG should be measured at days 2, 4 and 7 and then weekly. Levels should fall by 15% at each measurement, if they do not arrange senior review.
Single dose methotrexate (though some may require subsequent doses) may be considered as an alternative to surgery.
NICE guidelines 126 advise the following women are offered methotrexate:
A choice of either methotrexate or surgical management should be offered to women with a B-hCG level 1,500-5,000 IU/litre, who are able to return for follow-up and meet all of these criteria:
Those managed with methotrexate should have serum B-hCG measured at days 4 and 7 and then weekly. If levels plateau or rise arrange senior review.
When indicated the laparoscopic approach should be used over open surgery when possible. In tubal ectopics salpingectomy is preferred to salpingotomy if the contralateral tube is healthy.
If the contralateral tube is damaged or there are other fertility based concerns consider salpingotomy.
Emergency surgery is indicated in patients with a ruptured ectopic pregnancy. If the patient is unstable, assess in an ABCDE manner, escalate with peri-arrest and/or major haemorrhage call.
NICE guidelines 126 advise the following women are offered surgery as first line management:
Patients who have required salpingotomy require weekly serum B-HCG measurements until negative. Approximately 1 in 5 will need further treatment (methotrexate, salpingectomy).
Women who have had a salpingectomy should conduct a urinary pregnancy test at three weeks and contact the gynaecology department if positive.
Rhesus-negative women may require anti-D rhesus prophylaxis.
The NICE guidance 126 states anti-D rhesus prophylaxis should be offered to all women who have surgery to manage an ectopic pregnancy.
The RCOG/AEPU Joint Guideline advise anti-D rhesus prophylaxis should be offered to all women who have surgery to manage an ectopic pregnancy or where bleeding is repeated, heavy or associated with abdominal pain.
An ectopic pregnancy can be one of the most traumatic experiences of a women’s life.
They have to cope with losing a pregnancy during a potentially life threatening condition. There are also potential issues with future fertility to contend with. A huge range of emotions may be experienced and will differ, patient too patient. It will also affect partners and close family and can put strain on relationships.
Counselling is an individual decision though many women will find it helps following an ectopic pregnancy. In addition a number of charities offer support and guidance for both patients and clinicians:
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