Ectopic Pregnancy: The Hidden Threat in Pregnancy of Unknown Location

Objective: To highlight the need for a high index of suspicion for ectopic pregnancies (EP) in

pregnancies of unknown locations (PUL) and to remain vigilant for the risk of EP rupture in

medical management.

Case Report: A 23 year-old primiparous lady presented to the early pregnancy unit (EPU) with

per-vaginal spotting following 6 weeks and 2 days of amenorrhoea. A pregnancy was not

demonstrated on transvaginal ultrasound (TVUS) and serum beta-human chorionic

gonodotrophin (β-hCG) was 746.4IU/L. A repeat β-hCG after 48 hours was 1543.6IU/L,

showing a 106% rise; she was now asymptomatic. Another TVUS was offered which showed

an empty uterus and a 1.2cm echogenic structure with a cystic space adjacent to the right

ovary with no free fluid, suggestive of an unruptured right tubal EP . The patient opted for

systemic methotrexate, administered in a single dose at 50mg/m . β-hCG levels were

repeated on days 4 and 7 which were 3320.1IU/L and 2818.7IU/L respectively, demonstrating

a 15.1% decrease. She remained asymptomatic at both reviews. However, on day 10, she

presented with sudden onset severe abdominal pain. TVUS showed heterogenous free fluid

adjacent to the known EP with significant probe tenderness. An emergency laparoscopy

confirmed a 5cm ruptured tubal EP and she underwent a right salpingectomy and made an

uneventful postoperative recovery.

Discussion: This case report highlights the importance of offering an early TVUS to women

with PUL and β-hCG >1500IU/L to aid in early diagnosis and thus treatment of EP . Clinicians

are also cautioned against false reassurance from an optimal β-hCG rise and to remain

cognizant of the risk of EP until an intrauterine pregnancy is visualized on ultrasound. It is

estimated that 15-20% of EP demonstrate β-hCG rises similar to a progressive intrauterine

pregnancy. Additionally, it stresses the need for vigilance amongst clinicians for an EP rupture

despite appropriately decreasing β-hCG levels post-methotrexate. Patients should be

counselled adequately and given return advice for such contingencies.