Low ferritin: The little-known reason for chronic sleep issues in children that’s more common than you think

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 simple behavior. 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.

Low Ferritin and Sleep Problems

Ferritin refers to the iron storage capacity in the blood. This is different from 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. Some children start off with potentially lower levels of ferritin as a result of gestation, early cord clamping, or other physiological issues that can reduce how iron is absorbed by the gut. When ferritin starts to run low, it causes a cascade of effects in the body.

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. In younger children, they may call it Periodic Limb Movement Disorder. Older children 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 a sign of low ferritin.

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 protests. We think a child just can’t settle, but in fact, they are really and truly desperately uncomfortable.

I can tell you that all three of those clients from above came back with very low ferritin levels.

Symptoms

Low ferritin can occur in even very young children. We are more familiar with the symptoms of older children because they can tell us what’s bothering them. In infants and toddlers, we only have behaviors to go on. Researchers only diagnose RLS in older children, but acknowledge that in most of those cases, symptoms began in infancy and toddlerhood.

• [Older children] They will say their legs feel “jumpy” “tickly” “prickly” or that they hurt. (We now think that “growing pains” are actually RLS.)
• [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] Babies and children will be consistently awake for several hours each night. It will also seem like nothing works reliably to get them back down.
• A wide variety of behavioral strategies haven’t worked…at all.
• 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 can be as low as 7). 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 usually 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.

References
Dosman, C., Witmans, M., & Zwaigenbaum, L. (2012). Iron’s role in paediatric restless legs syndrome: A review. Paediatrics & Child Health, 17(4), 193–197. https://doi.org/10.1093/pch/17.4.193
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
Picchietti, D. L., & Stevens, H. E. (2008). Early manifestations of restless legs syndrome in childhood and adolescence. Sleep Medicine, 9(7), 770–781. https://doi.org/10.1016/j.sleep.2007.08.012

Macall Gordon has a B.S. from Stanford in Human Biology and an M.A. from Antioch University, Seattle in Applied Psychology, where she is currently a Sr. Lecturer in the mental health counseling and art therapy departments. She researches and writes about the relationship between temperament and sleep, and the gap between research and parenting advice. She is a certified pediatric sleep consultant working with parents of alert, non-sleeping children in private practice, as well as on the women’s telehealth platform, Maven Clinic. She comes to this work because she had two sensitive, intense children and she didn’t sleep for 18 years.