A 16-year-old adolescent, with a history of constipation, presented at the emergency department (ED) with an abdominal pain, located in the lower quadrants of the abdomen and radiating bilaterally to the lumbar region. The pain had started 6 hours prior to her hospital admission. She reported an increase in abdominal volume over the previous week and noted that her last bowel movement had occurred 4 days prior. According to her information, the last menstrual period had been 30 days before her presentation, and she denied any history of sexual intercourse or any other symptoms.
Upon examination, the abdomen was distended and not depressible, with a palpable abdominal mass extending from the lower quadrants to approximately 5 fingers above the umbilical scar.
An immunological diagnosis of pregnancy was requested, but it was negative, and an abdominal ultrasound was not available at the time.
Relying the information given, an abdominal X-ray was performed, revealing bone structures consistent with a fetus in a cephalic position (Figure 1). The patient underwent evaluation by obstetric specialists, who confirmed a full-term pregnancy in active labor.
Figure 1. Abdominal x-ray showing bone structures compatible with a fetus.
How come the urinary pregnancy test was negative?