Bilious vomiting in a neonate

A female newborn was delivered at full term via emergency caesarean section after an abnormal cardiotocograph trace during spontaneous labour. Her mother was a primigravida with no history of medical or obstetric problems, and the antenatal history was unremarkable for any sonographic abnormalities or growth issues. As the mother had developed a fever during delivery, the infant was started on antibiotics (benzylpenicillin and metronidazole) owing to concerns about maternal sepsis. The baby passed meconium soon after birth, tolerated breastfeeds well, and opened bowels spontaneously, with no rectal bleeding.

Two days after delivery, the baby had two episodes of non-projectile bilious vomiting, with no haematemesis. Observations were all within normal range, with no recorded fever or oxygen requirement. The infant showed no increased respiratory effort and no bradycardias or desaturations during examination. Her abdomen was distended but soft, with no discoloration, and bowel sounds were normal with ongoing bowel motions.

Blood test results at birth showed a normal white cell count of 10.6×10⁹/L and C reactive protein of <2 mg/L. Two days after delivery, the corresponding blood test results were 5.1×10⁹/L and 32 mg/L. Anteroposterior and lateral radiographs were requested (fig 1, fig 2).