Ectopic pregnancy is when a pregnancy is implanted outside the uterus. The most common site is a fallopian tube. An ectopic pregnancy can also implant in the entrance to the fallopian tube (cornual region), ovary, cervix or abdomen.
Certain factors can increase the risk of ectopic pregnancy:
- Previous ectopic pregnancy
- Previous pelvic inflammatory disease
- Previous surgery to the fallopian tubes
- Intrauterine devices (coils)
- Older age
Ectopic pregnancy typically presents around 6 – 8 weeks gestation.
Have a low threshold for suspecting an ectopic pregnancy, even in atypical presentations. Always ask about the possibility of pregnancy, missed periods and recent unprotected sex in women presenting with lower abdominal pain.
The classic features of an ectopic pregnancy include:
- Missed period
- Constant lower abdominal pain in the right or left iliac fossa
- Vaginal bleeding
- Lower abdominal or pelvic tenderness
- Cervical motion tenderness (pain when moving the cervix during a bimanual examination)
It is also worth asking about:
- Dizziness or syncope (blood loss)
- Shoulder tip pain (peritonitis)
A transvaginal ultrasound scan is the investigation of choice for diagnosing a miscarriage. A gestational sac containing a yolk sac or fetal pole may be seen in a fallopian tube.
Sometimes a non-specific mass may be seen in the tube. When a mass containing an empty gestational sac is seen, this may be referred to as the “blob sign”, “bagel sign” or “tubal ring sign” (all referring to the same appearance).
A mass representing a tubal ectopic pregnancy moves separately to the ovary. The mass may look similar to a corpus luteum; however, a corpus luteum will move with the ovary.
Features that may also indicate an ectopic pregnancy are:
- An empty uterus
- Fluid in the uterus, which may be mistaken as a gestational sac (“pseudogestational sac”)
Pregnancy of Unknown Location
A pregnancy of unknown location (PUL) is when the woman has a positive pregnancy test and there is no evidence of pregnancy on the ultrasound scan. In this scenario, an ectopic pregnancy cannot be excluded, and careful follow up needs to be in place until a diagnosis can be confirmed.
Serum human chorionic gonadotropin (hCG) can be tracked over time to help monitor a pregnancy of unknown location. The serum hGC level is repeated after 48 hours, to measure the change from baseline.
The developing syncytiotrophoblast of the pregnancy produces hCG. In an intrauterine pregnancy, the hCG will roughly double every 48 hours. This will not be the case in a miscarriage or ectopic pregnancy.
A rise of more than 63% after 48 hours is likely to indicate an intrauterine pregnancy. A repeat ultrasound scan is required after 1 – 2 weeks to confirm an intrauterine pregnancy. A pregnancy should be visible on an ultrasound scan once the hCG level is above 1500 IU / l.
A rise of less than 63% after 48 hours may indicate an ectopic pregnancy. When this happens the patient needs close monitoring and review.
A fall of more than 50% is likely to indicate a miscarriage. A urine pregnancy test should be performed after 2 weeks to confirm the miscarriage is complete.
Monitoring the clinical signs and symptoms is more important than tracking the hCG level, and any change in symptoms needs careful assessment.
Perform a pregnancy test in all women with abdominal or pelvic pain that may be caused by an ectopic pregnancy. Women with pelvic pain or tenderness and a positive pregnancy test need to be referred to an early pregnancy assessment unit (EPAU) or gynaecology service.
All ectopic pregnancies need to be terminated. An ectopic pregnancy is not a viable pregnancy.
There are three options for terminating an ectopic pregnancy:
- Expectant management (awaiting natural termination)
- Medical management (methotrexate)
- Surgical management (salpingectomy or salpingotomy)
Criteria for expectant management:
- Follow up needs to be possible to ensure successful termination
- The ectopic needs to be unruptured
- Adnexal mass < 35mm
- No visible heartbeat
- No significant pain
- HCG level < 1500 IU / l
Women with expectant management need careful follow up with close monitoring of hCG levels, and quick and easy access to services if their condition changes.
Criteria for methotrexate are the same as expectant management, except:
- HCG level must be < 5000 IU / l
- Confirmed absence of intrauterine pregnancy on ultrasound
Management with Methotrexate
Methotrexate is highly teratogenic (harmful to pregnancy). It is given as an intramuscular injection into a buttock. This halts the progress of the pregnancy and results in spontaneous termination.
Women treated with methotrexate are advised not to get pregnant for 3 months following treatment. This is because the harmful effects of methotrexate on pregnancy can last this long.
Common side effects of methotrexate include:
- Vaginal bleeding
- Nausea and vomiting
- Abdominal pain
- Stomatitis (inflammation of the mouth)
Anyone that does not meet the criteria for expectant or medical management requires surgical management. Most patients with an ectopic pregnancy will require surgical management. This include those with:
- Adnexal mass > 35mm
- Visible heartbeat
- HCG levels > 5000 IU / l
There are two options for surgical management of ectopic pregnancy:
- Laparoscopic salpingectomy
- Laparoscopic salpingotomy
Laparoscopic salpingectomy is the first-line treatment for ectopic pregnancy. This involves a general anaesthetic and key-hole surgery with removal of the affected fallopian tube, along with the ectopic pregnancy inside the tube.
Laparoscopic salpingotomy may be used in women at increased risk of infertility due to damage to the other tube. The aim is to avoid removing the affected fallopian tube. A cut is made in the fallopian tube, the ectopic pregnancy is removed, and the tube is closed.
There is an increased risk of failure to remove the ectopic pregnancy with salpingotomy compared with salpingectomy. NICE state up to 1 in 5 women having salpingotomy may need further treatment with methotrexate or salpingectomy.
Anti-rhesus D prophylaxis is given to rhesus negative women having surgical management of ectopic pregnancy.
Last updated August 2020