Obstetrics and gynaecology · Moderate
This case is fictional and exists for study. It describes no real patient.
29 years · female
A 29-year-old female presents to the emergency department with a 2-day history of right-sided lower abdominal pain and light, dark vaginal bleeding. Her last menstrual period was 6 weeks ago. She has a history of pelvic inflammatory disease treated 2 years ago. On examination, she is alert and oriented. Abdominal examination reveals mild tenderness in the right iliac fossa without rebound or guarding. Bimanual pelvic examination demonstrates cervical motion tenderness and mild right adnexal tenderness. Speculum examination reveals a closed cervical os with minimal dark blood in the vaginal vault.
Vital signs
- HR
- 82 bpm
- BP
- 118/74 mmHg
- RR
- 16/min
- Temp
- 36.8 °C
- SpO₂
- 99%
Examination findings
- Right iliac fossa tenderness
- Cervical motion tenderness
- Right adnexal tenderness
- Closed cervical os
Investigations
| Serum beta-hCG | 1400 IU/L | reference: < 5 (non-pregnant) |
| Haemoglobin | 12.8 g/dL | reference: 12.0-15.5 |
| Platelets | 240 10^9/L | reference: 150-400 |
Question 1 of 3
Which of the following is the most appropriate next step in management to confirm the diagnosis?
Transvaginal ultrasound (TVUS) is the gold standard initial imaging modality to identify the location of a pregnancy in early gestations presenting with pain or bleeding. Abdominal/pelvic CT is not indicated due to radiation and inferior pelvic soft-tissue resolution. Repeat serum beta-hCG in 48 hours is useful in pregnancy of unknown location (PUL), but imaging should be performed first. Diagnostic laparoscopy is reserved for definitive management or when imaging is inconclusive in unstable patients.
Teaching point: Transvaginal ultrasound is the primary imaging modality of choice for suspected ectopic pregnancy.
Question 2 of 3
A transvaginal ultrasound scan shows an empty uterine cavity with an endometrial thickness of 10 mm. An ectopic mass measuring 2.2 cm is visualized in the right fallopian tube with no embryonic heartbeat, and there is no free fluid in the pouch of Douglas. How should these imaging findings be interpreted?
The identification of an adnexal mass distinct from the ovary in the presence of an empty uterine cavity confirms an ectopic pregnancy. The absence of free pelvic fluid and small mass size without a heartbeat indicate that it is an unruptured tubal ectopic pregnancy. A complete miscarriage would show an empty uterus without an adnexal mass. Pregnancy of unknown location applies when TVUS shows neither an intra-uterine pregnancy nor an extra-uterine pregnancy.
Teaching point: An adnexal mass seen on transvaginal ultrasound in the absence of an intrauterine pregnancy confirms an ectopic pregnancy.
Question 3 of 3
Following confirmation of an unruptured right tubal ectopic pregnancy, the patient remains haemodynamically stable with minimal pain, a serum beta-hCG of 1400 IU/L, and an adnexal mass size of 2.2 cm with no fetal heartbeat. What is the next best management step?
According to NICE guidelines, medical management with single-dose intramuscular methotrexate is offered to haemodynamically stable women with an unruptured ectopic pregnancy, an adnexal mass < 35 mm, no visible fetal heartbeat, no severe pain, and serum beta-hCG < 1500 IU/L. Surgical management (salpingectomy) is indicated if the patient has severe pain, mass > 35 mm, visible heartbeat, or hCG >= 5000 IU/L. Expectant management is considered when hCG is lower (< 1000 IU/L) and declining.
Teaching point: Intramuscular methotrexate is first-line medical treatment for unruptured ectopic pregnancy in stable patients meeting specific criteria, including hCG < 1500 IU/L.
Key learning points
- Transvaginal ultrasound is the initial imaging modality for suspected ectopic pregnancy.
- Risk factors for ectopic pregnancy include prior pelvic inflammatory disease, tubal surgery, and previous ectopic pregnancy.
- NICE guidelines support single-dose intramuscular methotrexate for haemodynamically stable women with an unruptured ectopic pregnancy < 35 mm, no fetal heartbeat, and serum beta-hCG < 1500 IU/L.
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