These soft spots are spaces between the bones of the skull where bone formation isn't complete. This allows the skull to be molded during birth. The smaller spot at the back usually closes by age 2 to 3 months. The larger spot toward the front often closes around age 18 months.

When should fontanelles close?

The posterior fontanelle usually closes by age 1 or 2 months. It may already be closed at birth. The anterior fontanelle usually closes sometime between 9 months and 18 months.

When should I be concerned about my baby's soft spot?

If you notice a bulging fontanelle along with a fever or excessive drowsiness, seek medical attention right away. A fontanelle that doesn't seem to be closing. Talk with your doctor if your baby's soft spots haven't started getting smaller by her first birthday.