A cephalohematoma is a relatively common birth injury involving a collection of blood on a newborn’s head. This condition is not a brain injury, but the visible swelling often causes parents concern. It is almost always benign and resolves completely on its own. Parents primarily want to understand the typical progression and how long the body takes to naturally absorb the trapped blood.
Anatomy and Causes of Cephalohematoma
A cephalohematoma forms when small blood vessels rupture, causing blood to pool beneath the periosteum, the thin membrane covering the skull bone. This specific location differentiates it from other types of newborn head swelling. Because the periosteum is tightly bound at the suture lines, the blood collection is confined to the surface of a single bone and cannot cross these boundaries. The lump may not be immediately visible at birth, often taking several hours or a full day to become noticeable.
The primary cause of this vessel damage is the pressure and minor trauma experienced during labor and delivery. A prolonged or difficult vaginal delivery increases the risk due to sustained force on the baby’s head. The use of obstetrical tools like vacuum extractors or forceps also raises the likelihood of a cephalohematoma forming, as these assisted delivery methods put focused pressure on the baby’s head.
The Standard Timeline for Absorption
The process of cephalohematoma resolution is gradual as the body works to break down and reabsorb the collected blood. Initially, the swelling appears as a soft mass, but within the first few days, the blood clot begins to organize and the lump often feels firmer. This solidification is a normal part of the healing process.
For most newborns, the reabsorption phase typically begins within the first couple of weeks. Smaller cephalohematomas often resolve completely in four to eight weeks. Larger collections of blood require more time for the body to process fully. The majority of cephalohematomas will resolve spontaneously and completely within three months of birth. The swelling usually shrinks from the center outward, which can temporarily create a firm, crater-like appearance along the edges.
Related Risks and Monitoring for Jaundice
As the body breaks down the trapped blood, the development of neonatal jaundice is a concern. Jaundice occurs because the reabsorption of a cephalohematoma involves the breakdown of red blood cells, which releases bilirubin, a yellowish waste product, into the bloodstream.
A newborn’s liver is often immature, making it less efficient at processing and eliminating this increased load of bilirubin. The resulting buildup of unconjugated bilirubin causes the characteristic yellowing of the skin and eyes. Healthcare providers monitor bilirubin levels closely in these infants, especially in the first few days of life. If the bilirubin level becomes too elevated, intervention like phototherapy may be necessary to help the body excrete the substance effectively.
When Healing Takes Longer Than Expected
While most cephalohematomas resolve within the three-month window, some may persist for longer periods. If the blood collection does not fully reabsorb within four to five weeks, a process called calcification, or ossification, can begin. This happens when the body deposits calcium around the edges of the clot, forming a hard, bony ring or shell.
A calcified cephalohematoma will feel like a hard lump and can take a year or more to fully flatten out as the bony material slowly remodels. This prolonged healing is usually a cosmetic issue and rarely medically significant, but it requires continued monitoring by a pediatrician. If a cephalohematoma becomes infected, presenting with signs like redness, warmth, or fever, immediate medical attention is required. Drainage or surgical intervention is almost never required for uncomplicated cases, and observation remains the standard management approach.