EARLY FONTANELLE CLOSURE
EARLY CLOSURE OR SMALL SIZE OF THE FONTANELLE MAY NOT BE A PROBLEM
What is a fontanelle?
A fontanelle - medically called a fontanel - is the soft area on your baby's skull where the skull bones have not yet joined. These areas allow the skull bones to shift during birth and pass through the birth canal, while also giving the brain room to grow. Fontanelles close as the baby grows. There are two main fontanelles:
- The anterior fontanelle is located on the front-top part of your baby's head. It is the larger one.
- The posterior fontanelle is located at the back of the head.
It is safe to gently touch your baby's fontanelle. A healthy fontanelle should feel soft and flat. A bulging or sunken fontanelle may be a sign of a health problem.
When does the fontanel close?
In general, fontanelles are expected to close by the time a baby is 18 months old. The posterior fontanelle closes first. The anterior fontanelle usually closes between 7 and 18 months.
These numbers are general population averages and do not have to fit every baby exactly. According to the medical literature, a fontanelle that closes between 3 and 18 months is VERY LIKELY not to cause any problem.
More important than the size of the fontanelle is your baby's head circumference growth rate and whether your baby is doing the expected activities for their age, in other words, whether neurological development is healthy. If you or your pediatrician are worried about an early-closing fontanelle, the best step is to consult a pediatric neurosurgeon without panic.
What happens if the fontanel closes early?
Sometimes the anterior fontanelle closes earlier than expected. In this situation, the first concern for pediatricians, and perhaps for you, may be whether your child's brain will continue to grow. Yes, fontanelles help brain growth, but early closure does not mean that brain growth will stop.
The list of diseases that can stop brain growth is long, and these diseases are usually serious conditions. Early fontanelle closure is not expected to be their first sign. When the brain does not grow and remains small, this is called microcephaly, a serious neurological condition that must be investigated carefully.
Another problem often associated with fontanelle closure is craniosynostosis, a condition in which the skull sutures close too early. In craniosynostosis, the problem is not the fontanelle itself, but the joints between the skull bones. This condition is very often congenital; it would not be wrong to say that the baby was born with it. A fontanelle closing at 3-4 months does not cause craniosynostosis.
In craniosynostosis, the child's head circumference growth does not stop and, of course, brain growth continues, except in very rare complex conditions called syndromic synostosis. In craniosynostosis, head growth becomes misshapen, and an experienced eye may recognize the problem immediately. You can learn more about craniosynostosis, one of the most common concerns when a baby's fontanelle closes early, from this link.
Are babies whose fontanelle closes early smarter?
A baby's intelligence is not related to fontanelle size. Intelligence develops through the combined effect of many genetic and environmental factors.
Is it wrong to use vitamin D in a baby whose fontanelle closes early?
Early fontanelle closure and vitamin D are very often linked in people's minds. Vitamin D is very important for bone development. The idea that "if the fontanelle is closing early, there is rapid bone formation, so it would be wrong to use vitamin D" is COMPLETELY WRONG. Even in craniosynostosis cases that require surgery, stopping vitamin D is not recommended. In fact, medical literature includes findings suggesting that vitamin D deficiency disrupts bone metabolism and may cause bones to behave unexpectedly. Vitamin D, and of course sunlight, are very important for babies' development. Especially in babies who do not have a medical problem related to vitamin D, supplements should not be stopped just because the fontanelle is small or closed.
What should I do if my baby's fontanel is too small or closed?
As explained above, this is very likely to cause no problem at all. What you should do is speak with a doctor experienced in this subject. In my own practice, I follow babies referred to me for early fontanelle closure with head circumference measurements for a few months. In head circumference follow-up, a single measurement is not enough; several past and future measurements are important. These measurements can be plotted on special charts to show the baby's head growth trend. If anything suspicious appears during this process, further evaluation is needed.