Last month the AAP made some headlines with their new car seat recommendations, saying:

“All infants and toddlers should ride in a rear facing [car seat] as long as possible, until they reach the highest weight or height allowed by their [car seat] manufacturer.”

Rear facing car seats have gotten larger over the years, which has been important for accommodating increasingly large toddlers, but many will go upwards of 50 pounds. Keeping a child rear-facing until they reach that weight could mean children are rear facing up to or even beyond 4 years of age.

Many of us woke up to that news and said “Really?”

I finally got a chance to review the Technical Report which supplies the underlying evidence for those recommendations, and I have to say that very little of it specifically addresses the 2-4 year age group. There are very good biomechanical reasons to differentiate the needs of younger children, including incomplete ossification of vertebra, excessive ligamentous laxity, and disproportionately large heads. All of these factors mean that rear facing seats will better support them in a crash. But these factors recede over time. So the critical question is: when have they diminished sufficiently to turn the seat around?

The report makes it clear that we really don’t have the data to answer that question. The authors describe how previously published studies of US crash data have been called into question and more recent reanalysis of that data showed only statistically insignificant changes because the sample size was not large enough.The report relies heavily on Swedish data, where rear facing seats are mandatory until 4 years of age. Researchers there report huge safety improvements as a result, decreasing risk by 90%, but relative to unrestrained children. Nothing in the report compares rear and front facing car seats in the 2-4 age range.

So the bottom line is: we really don’t know. Rear facing is certainly safest for the smallest children, but the safety benefits will diminish as they grow and it is difficult to say exactly when the difference between front and rear facing seats becomes insignificant. Pretty frustrating.

For my patients, I am drawing attention to the phrase “as long as possible” in the recommendation. Since rear facing seats are the safest, it makes sense to keep children rear facing as long as possible, but it may be reasonable to consider factors other than physical size in determining what is possible for individual families. There may be social and behavioral reasons, for example, that mean rear facing seats are no longer practical for individual children in that 2-4 year old range.

I still wouldn’t turn anyone forward under 2 years of age. That would likely be a bad idea. And after 2, if your child is happy and comfortable, there is no immediate urgency to turn them around. Keep them rear facing “as long as possible,” at least until they reach the limits of the car seat being used. But if an older child is forcefully objecting to facing out the back and you have reached the point where it no longer seems practical to do so, I think the data looks pretty weak that you need to keep them rear facing regardless until you max out the height/weight limits on the car seat label.