The soft spot feels like an epicenter in O’s landscape. As every new parent gets to know their baby, the soft spot is just one of those places and spaces we come to know that makes our baby unique. I know O’s little spot is about to go away. Just another thing for me to cry about at the two-year birthday party.
I took a phone call from the husband recently who is a pediatric radiologist and who was reading a head CT scan, inquiring when I thought the soft spot closed in infants, exactly. He knows a lot more anatomy, physiology and imaging of the skull than I do, but he had a common question: just when does it close? Like so many things in medicine, I don’t think it’s entirely clear. There is no perfect answer. The short answer is around 1-2 year of life. But like so many things, the range of normal is expansive.
Your baby may still have their soft spot when they start to run. See that spot run! Although closure of the soft spot that you feel, when you touch your baby’s head, can be as early as about 4-9 months, it can also be as late as 2 years. Soft spots in most children close at some point between 7 and 19 months of age. Variable sizes of soft spots are normal, too (see part 1). When I talked with Dr Kelly Evans a pediatrician specializing in craniofacial pediatrics, she told me, “what impresses me the most about the anterior fontanelle is the variability between babies.” When she was talking, it made me wonder if soft spots are like fingerprints and snowflakes. Maybe no two are exactly the same. I could be over-thinking this…
Most babies’ soft spots are hard to feel after about 1 year of age but that doesn’t mean the soft spot is closed. The only way to know when the soft spot is functionally closed is to evaluate the skull by CT scan (see part 1 for a view of an actual 3D, CT image). What we feel and what is actually remaining open are different. The variability of normal with the soft spot is vast. If you’re worried about the size or feel of your baby’s soft spot or head shape, ask your pediatrician at the next check up. Only rarely do we worry. It’s only when something else is suspicious (unusual head shape, poor/slow or excessive head circumference growth) that we worry about the timing of the soft spot closing.
Look at this graph. Okay, it’s from 1949 but it’s about as current as I can find and it’s the data that the craniofacial doctors use to explain this huge variability of soft spot closure. Dr Evans says there have not been any recent great studies evaluating timing of closure. The graph shows the perfect bell curve reflecting the time of closure of the soft spot in 1677 infants that researchers followed back before Elvis was Elvis. Babies in the study had soft spots close anywhere between 4 months and 2 years. This range is considered normal.
So, the soft spot may be closed when your baby just starts laughing (about 4 months) or when they are blowing out two candles on the cake. See—you really may see that spot, run.