Imaging of acute abdominal pain in the third trimester of pregnancy

A 25 year old woman at 29 weeks’ gestation in her first pregnancy presents to her local hospital with a 12 hour history of constant abdominal pain and vomiting. She has no relevant medical or surgical history, and the pregnancy has been uncomplicated. She reports normal fetal movements and no vaginal fluid or blood loss. On examination, she has a tachycardia of 100 beats/min, blood pressure 108/70 mmHg and a temperature of 37.9°C. Abdominal examination finds generalised abdominal tenderness without peritonism. On vaginal speculum examination, the cervix appears long and closed. Urinalysis is negative for blood, protein, leucocytes, and nitrites but shows ketonuria. Cardiotocography is performed, which confirms a normal fetal heart rate pattern with no evidence of uterine activity. Initial full blood count, electrolytes, renal, and liver function are normal, except for an elevated white cell count of 15.0×10⁹/L and C reactive protein of 11.5 mg/L.

Abdominal pain at all stages of pregnancy is a common presentation in both primary and secondary care. More serious causes of abdominal pain, such as appendicitis, can be associated with serious morbidity and mortality to both fetus and mother. Diagnosis and investigation of abdominal pain during pregnancy present specific challenges, particularly in the third trimester, where the large gravid uterus makes clinical and imaging assessment of abdominal pain more complex.

In this article, we present …