Ectopic pregnancy

Introduction

Ectopic pregnancies refer to anypregnancy that develops outside the endometrial cavity.

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 leads 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.

Risk factors

A number of factors increase the risk of ectopic pregnancy, however, the majority of women have no identifiable risk factor.

• Previous ectopic pregnancy (risk is around 18.5%)

• IVF

• Fallopian tube damage (may be secondary to infection, surgery)

• Adhesions

• Smoking

• Intrauterine contraceptive device (overall the risk of ectopic pregnancy, and any pregnancy, is reduced, however, in the event of failure the proportion of pregnancies that are ectopic is increased)

• Progestogen-only pill (overall the risk of ectopic pregnancy, and any pregnancy, is reduced, however, in the event of failure the proportion of pregnancies that are ectopic is increased)

  
  

Clinical features

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.

Symptoms

• Abdominal/pelvic pain

• Vaginal bleeding

• Amenorrhoea

• Shoulder tip pain (a sign of rupture and intra-abdominal bleeding, indicative of blood irritating the diaphragm)

• Urinary discomfort

• GI upset

Signs

• Abdominal/pelvic tenderness

• Rebound tenderness, peritonism

• Abdominal distention

• Pallor

• Cervical motion tenderness (refers to pain on movement of the cervix during a bimanual examination, indicative of pelvic inflammation)

Ruptured ectopic pregnancy

A ruptured ectopic pregnancy is a gynaecological emergency. There can be significant intra-abdominal bleeding leading to collapse 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.

Investigations

Trans-vaginal USS is the investigation of choice in the diagnosis of ectopic pregnancy.

Bedside

• Observations

• Urinary pregnancy test

• Urine dipstick

Bloods

• FBC

• U&Es

• CRP

• LFTs

• Clotting screen

• Group and saves

• Serum B-hCG (see chapter below for detail)

Imaging

Trans-vaginal USS: the standard investigation. It provides good visualisation and identifies the majority of tubal ectopic pregnancies during the 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 ectopic pregnancies.

Serum B-HCG

Serum beta-human chorionic gonadotropin (B-hCG) is used to help guide the management of ectopic pregnancy.

Management

Management of ectopic pregnancy falls into three main types; expectant, pharmacological and surgical.

Expectant management

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:

• Clinically stable and pain-free and

• Unruptured tubal ectopic pregnancy measuring less than 35 mm with no visible heartbeat on transvaginal ultrasound scan and

• Serum B-hCG levels of 1,000 IU/L or less and

• Able to return for follow-up

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.

Pharmacological management

Single-dose methotrexate (though some may require subsequent doses) can be considered as an alternative to surgery.

NICE guidelines 126 advise the following women are offered methotrexate:

• Have no significant pain and

• Have an unruptured tubal ectopic pregnancywith an adnexal mass smaller than 35 mm with no visible heartbeat and

• Have a serum B-hCG level less than 1,500 IU/litre and

• Do not have an intrauterine pregnancy (as confirmed on an ultrasound scan) and

• Able to return for follow-up

Surgical management

There are a number of indications for surgery, when indicated the laparoscopic approach should be used over open surgery when possible. There are two main terms to be aware of in the surgical management of tubal ectopics:

• Laparoscopic salpingectomy: laparoscopy refers to 'key-hole' surgery. Salpingectomy refers to the removal of a fallopian tube, in this case, the tube affected by the ectopic pregnancy. This is generally the preferred treatment.

• Laparoscopic salpingotomy: this refers to a procedure that aims to preserve the fallopian tube. The tube is opened and the ectopic is removed. It is generally considered if the contralateral tube is damaged or there are other fertility-based concerns.

Anti-D rhesus prophylaxis

Rhesus D (RhD) negative women may require anti-D rhesus prophylaxis.

Rhesus (Rh) refers to a group of red cell antigens, the most important being RhD. Problems arise when RhD-negative mothers have RhD-positive foetuses. Feto-maternal haemorrhage (FMH) can expose the mother to RhD-positive blood. In response, a RhD-negative mother generates anti(D) antibodies. In subsequent pregnancies anti(D) antibodies can cross the placenta and lead to haemolytic disease of the newborn.

Anti-D immunoglobulin is given to reduce the risk of maternal sensitisation in events where FMH is likely.