Timing of Infant Anterior Fontanelle Closure

The anterior fontanelle (commonly referred to as the “soft spot” or “crown fontanelle”) is a critical anatomical feature in infants, and parents must take special care to prevent injury to this area. So, when does the anterior fontanelle close?

Timing of Anterior Fontanelle Closure

Typically, the anterior fontanelle closes no later than 18 months after birth. In some infants, closure may occur much earlier—often between 5 and 6 months of age. A normal anterior fontanelle appears flat or slightly depressed and pulsates gently in synchrony with the infant’s heartbeat; it feels soft and yielding upon light palpation. Premature closure before 6 months may indicate microcephaly or impaired brain development. Conversely, failure to close by 18 months is considered delayed and may suggest underlying conditions such as hydrocephalus, rickets, or hypothyroidism. A bulging fontanelle may signal increased intracranial pressure and warrants prompt medical evaluation.

Avoid using hard pillows such as mung bean pillows or sand-filled pillows, as these can cause cranial or fontanelle deformation. To promote optimal head shape development, regularly reposition your baby—change their sleeping position and encourage frequent turning. Infants are naturally drawn to light; if your baby habitually sleeps on one side, you can use light to gently encourage them to turn toward the opposite side. Protect your baby’s head by ensuring household furniture has no sharp or hard edges that could injure the scalp. Should an accidental scalp laceration occur, immediately disinfect the wound with an alcohol-soaked cotton ball to prevent infection.

During summer outings, protect your baby from excessive heat by having them wear a sun hat—this helps prevent overheating and potential heatstroke related to elevated temperature at the fontanelle. In winter, ensure your baby wears a warm, thick hat to safeguard the fontanelle while minimizing heat loss. We hope this information proves helpful!