University of Melbourne researcher Dr Andrew Tagg and some paediatrician colleagues looked at how long it takes Lego to exit the digestive system
“Children frequently ingest coins (generally with minimal reported side effects); however, the ingestion of other items has been subject to less academic study,” write the six doctors in the Journal of Paediatrics and Child Health.
“Parental concern regarding ingestion applies across a range of materials.
“In this study, we aimed to determine typical transit times for another commonly swallowed object: a Lego figurine head.”
The doctors each swallowed a single head with water, having excluded any colleagues who had had previous gastrointestinal surgery, inability to ingest foreign objects and aversion to searching through their poo to see if the head had appeared.
The doctors standardised pre-ingestion bowel habit via their Stool Hardness and Transit (SHAT) score.
After each swallowing a head, they measured the time it took to show up in their faeces, thus generating the Found and Retrieved Time (FART) score.
While a few foreign items ingested by children, such as button batteries, are dangerous, most are inert and not of concern, they write.
Five of the six participants were able to locate their Lego head in their stool following ingestion, while one male participant looked for two weeks without success.
“Of the successfully retrieved Lego heads, the number of bowel motions searched ranged from one to three, with an average of two bowel motions,” the authors wrote.
“The females appeared to have faster passage of the foreign body, retrieving the Lego head within two bowel motions, whereas the two males who retrieved their Lego heads both did so on their third bowel motion.
“The principal finding of this study, the FART score (n = 5), ranged from 1.14 days (27 h 20 min) to 3.04 days (72 h 35 min), with an average retrieval time of 1.71 days.
“Comparing the stool diaries pre‐ and post‐ingestion, there was no significant difference in consistency of stool over time. The pre‐SHAT score (n = 6) ranged from 3 to 5.67 prior to ingestion, and the SHAT score (n = 5) ranged from 2.96 to 7.76.
“Comparing these two markers using a Wilcoxon signed rank test demonstrates no significance (αtwo‐tailed ≤ 0.1) between Bristol Stool Scores over time before and after ingestion.
“This suggests that the ingestion of the Lego heads did not appear to have a significant impact on the consistency of bowel motions in participants.”
The authors wrote that there is little evidence to show a child’s bowel transit time would differ greatly to an adult’s, and that the Lego heads passed through the adult subjects in one to three days without complications.
“Parents should be counselled not to search for the object in stools as it is difficult to find,” they wrote.
“If an experienced clinician with a PhD is unable to adequately find objects in their own stool, it seems clear that we should not be expecting parents to do so – the authors feel that national guidance could include this advice.”
There are some limitations to the study, they warn.
“The population studied could not be blinded to the study outcomes as we felt it was unfair on the authors’ partners or colleagues to search through their waste products.
“We also recognise that the Stool Hardness and Transit score is not a perfect surrogate for underlying bowel pattern, but the fact that participants can SHAT themselves without specialist knowledge makes it an inexpensive tool.”