Here's some good news for worried parents whose small children have ingested a LEGO (or two). A new study by pediatric researchers has concluded that the toy should re-emerge in their poo within a couple of days. They know this because their test subjects voluntarily swallowed LEGO figurine heads and monitored how long it took to retrieve them.

Yes, this is an actual scientific paper, published in the reputable Journal of Pediatrics and Child Health with the title, "Everything is Awesome: Don't Forget the LEGOs." It's by the same group of pediatricians behind the popular blog Don't Forget the Bubbles. "We've finally answered the burning question: how long does it take for an ingested LEGO head to pass?" DFTB co-founder and paper co-author Tessa Davis tweeted. "This is dedication to pediatrics. But it was worth it to advance science and pediatric emergency care."

We jest, but this really is addressing a valid concern. As Bruce Y. Lee, a professor at Johns Hopkins Bloomberg School of Public Health, pointed out at Forbes, small children love to swallow things, particularly coins. There have been prior studies examining the passage of coins through the digestive tract, notably a 1971 paper that found most coins passed through harmlessly within three to six days.

But no one had looked closely at the second most commonly swallowed item: small toy parts. And LEGO figurine heads are particularly tempting for the gastronomically curious toddler.

How would you even find six adults (three men and three women) willing to swallow LEGO parts? Davis et al. recruited their subjects from the online community of pediatric hospital professionals. They screened out anyone with previous gastrointestinal surgery, problems swallowing objects, or an "aversion to searching through fecal matter."

Each subject kept a "stool diary," recording their bowel movements before and after swallowing the LEGO heads. They evaluated the frequency and looseness of their stool based on the research team's Stool Hardness and Transit (SHAT) score. (Who says pediatricians don't have a sense of humor?) After swallowing the toy, they spent the next three days sifting through their own poo to determine when the LEGO head reappeared. The number of days it took to pass and retrieve it was dubbed the Found and Retrieved Time (FART) score.

One poor sod never retrieved the LEGO head at all.

Five of the six subjects had FART scores ranging from 1.14 days to 3.04 days, for an average of 1.71 days (about 41 hours). And one poor sod never retrieved the LEGO head at all. We now know that subject is paper co-author and pediatrics consultant Damien Roland, who told the CBC he kept searching through his own poo for two weeks, hoping the toy part would reappear, to no avail. Maybe a bit more roughage in the diet would help?

As Lee points out, this is a small study, focusing on adults rather than toddlers. SHAT and FART scores might vary more widely in the general population. Nor was this a blind study, since the authors felt it would just be asking too much of the study participants' partners or colleagues to sift through poo on their behalf. And other small toy parts of varying shapes might take shorter or longer times to pass through the body.

"A toy object quickly passes through adult subjects with no complications," the authors conclude, adding one important caveat: "parents should be counseled not to search for the object in stools as it is difficult to find." But also maybe don't swallow those LEGO figurine heads in the first place, m'kay?

DOI: Journal of Paediatrics and Child Health, 2018. 10.1111/jpc.14309 (About DOIs).