As a sleep coach, I often see clients only after they have tried everything under the sun with no luck. Recently, I have had a run of clients with really severe issues that just didn’t sound like a simple behavioral issue. One client had a toddler who was awake every night for hours and only wanted mom to hold him with his legs dangling down. Every time she tried to lay him down, he screamed. Another client had a 3-year-old who was bouncing off the walls at bedtime (a little normal), but then was also awake from 2-5 a.m. every night and nothing worked to get him back to sleep. A third client had a 7-month-old who couldn’t tolerate not nursing through the entire night and would scream if mom even tried to move away or unlatch. These are not “normal” behavioral issues. Something else is going on here.
I ran across a research article on the role of low ferritin in the blood and its effect on both sleep structure and behavior. Ferritin refers to the iron storage capacity in the blood. This is different from hemoglobin or the amount of iron in the blood. Individuals can have enough iron, but if it’s not absorbed or stored, the body isn’t as able to utilize it.
Low ferritin alters the very structure or architecture of sleep in the brain. It is also related to significant discomfort that resembles Restless Legs Syndrome. Individuals with RLS will say that their legs feel “twitchy” or “jumpy” and they can’t get comfortable. Dr. Lewis Kass, pediatric pulmonologist, suggests that much of what we used to call “growing pains” is likely due to low ferritin and its impacts on the body.
Low ferritin makes bedtime and nighttime incredibly difficult. RLS symptoms tend to occur more at bedtime/nighttime. Behaviors that stem from RLS unfortunately can masquerade as garden variety bedtime protest. We think a child just can’t calm down, but in fact, they are really and truly desperately uncomfortable.
I can tell you that all three of those clients came back with very low ferritin levels.
Symptoms: Low ferritin can occur in even very young children. We are more familiar with symptoms of older children because they can tell us what’s bothering them. In infants and toddlers, we only have behaviors to go on. Here are some to consider:
[Older children] They will say their legs feel “jumpy” “tickly” “prickly” or that they hurt.
[Children in a bed] They take a long time to go to sleep. They want to be rocked, then not rocked. They want covers, then no covers. As a parent, it seems like they just can’t get comfortable.
[Middle of the night] These children will be consistently awake for several hours each night. It will also seem like nothing works reliably to get them back down.
If you have tried a wide variety of strategies but nothing has made a difference
The child wakes at night moaning or in other ways uncomfortable (i.e., simple strategies don’t get them back down)
For infants, extreme difficulty with anything but full body contact, constant nursing, etc. (i.e., baby screams if nursing stops or parent tries to move away)
If your child has a food intolerance (e.g., milk, wheat), they may be more prone to low ferritin since gut inflammation can hinder iron absorption.
Mom had low iron in pregnancy or either parent had a history of low iron/ferritin or either parent has Restless Legs Syndrome.
Testing: Ferritin can be tested with a simple blood draw (I know, I know. That’s actually not that simple.) Results should come back quickly. The usual lower threshold for “normal” ferritin is considered too low when it comes to sleep. Sleep doctors generally want the score to be above 50 (normal lower end is 22). If your child is having significant sleep issues and the score comes back on what the pediatrician might say is “the lower end of normal,” consult a sleep doctor to be sure.
Treatment: Treatment for low ferritin is iron supplementation. Depending on how low the score is, your child might need a doctor-prescribed supplement (i.e., multivitamins with iron or iron-rich foods won’t cut it.) Ferritin levels can take months to come up to the higher threshold, however, you should see improvement in sleep behaviors within a few weeks. In the meantime, stretching or leg massages can work at bedtime. Mild heat can also help symptoms.
If you feel like your child’s sleep behavior is more than just a behavioral issue, get their ferritin checked.
Peirano, P. D., Algarín, C. R., Chamorro, R. A., Reyes, S. C., Durán, S. A., Garrido, M. I., & Lozoff, B. (2010). Sleep alterations and iron deficiency anemia in infancy. Sleep Medicine, 11(7), 637–642. https://doi.org/10.1016/j.sleep.2010.03.014