Ectopic pregnancy and pregnancy of unknown location

 Risk factors for ectopic pregnancy

• Previous ectopic pregnancy
• Known inflammatory condition, for example, pelvic inflammatory disease (PID), endometriosis
• IUCD
• IVF
• Previous surgery or instrumentation (eg, caesarean section, tubal ligation).

Clinical signs and symptoms

Clinical diagnosis may be difficult because the symptoms and signs are often non-specific, but they will include:

• pain
• PV bleeding (vaginal bleeding)
• a positive pregnancy test
• poorly rising serum βhCG
• signs of haemodynamic instability (eg, drowsiness, fatigue, pale skin, sweating).

Atypical symptoms and signs

In up to 70 percent of cases, there will be:

• vague discomfort
• contralateral pain
• no PV bleeding
• back pain, vaginal pain, bowel symptoms
• low or normal serum βhCG
• asymptomatic.

Sonographic features of ectopic pregnancy

Sonographic features of ectopic pregnancy may include:

• no intrauterine gestational sac
• endometrial pseudogestational sac (see Appendix 4: Findings in ectopic pregnancy)
• adnexal mass
• free fluid or haemoperitoneum (see Appendix 4: Findings in ectopic pregnancy).

Ectopic pregnancy ultrasound examination

• Sac location – atypical location of the gestational sac in relation to the endometrial cavity should be reported. This is particularly important for:
  • low-positioned gestational sac, adjacent to or bulging into a caesarean section scar (see Appendix 2)
  • cornual or cervical location, separate to the endometrial cavity (often best shown on three-dimensional coronal imaging); document overlying myometrial thickness
  • yolk sac
• Embryo (fetal pole)
• CRL
• Embryonic cardiac activity – document with a cine clip if possible; otherwise annotate cardiac activity present or absent on the relevant image
• Adnexa
• Document free fluid.

Reporting guide and referral recommendations

Minimum reporting requirements

Scan technique (TA/TV). Document if the woman declined a TV scan.

Document findings as per Ectopic pregnancy ultrasound examination (see above):

• sac location (see Appendix 3: Ectopic pregnancy location)
• CRL (date pregnancy if embryo is present)
• MSD if no embryo identified
• cardiac activity
• adnexal mass or haemorrhage
• largest diameter of ectopic mass or gestational sac
• free fluid – location and amount (document free fluid at or above the uterine fundus).

Note: It is strongly recommended that a βhCG result is available at the time of the ultrasound scan.

There is no defined cut-off βhCG level at which ectopic pregnancy can be excluded.

Rather, it is the change in hCG over time that is of value.

The clinical scenario in which there is a positive pregnancy test and in which there is no sonographic evidence of intra- or extra-uterine pregnancy and where there are no obvious retained products of conception on TVS, is defined as a pregnancy of unknown location (PUL).

Under these circumstances, there are three possibilities.

• Early intrauterine pregnancy
• Ectopic pregnancy
• Early pregnancy loss.