A cephalohematoma is a collection of blood that forms between a newborn’s skull bone and the tough membrane (periosteum) that covers it. It shows up as a soft, raised bump on one side of the baby’s head, typically appearing within the first one to three days after birth rather than right away. It occurs in roughly 2.5% of prolonged or difficult vaginal deliveries, and the rate climbs to about 1 in 10 babies delivered with vacuum extraction or forceps.
Though it can look alarming, a cephalohematoma is not a brain injury. The blood sits on the outside of the skull, not inside it, and the vast majority resolve on their own without treatment.
Why It Doesn’t Appear Right Away
During delivery, pressure on the baby’s head can rupture tiny blood vessels just beneath the periosteum. Because these are small capillaries rather than large veins, the bleeding is slow. The bump usually isn’t visible at birth. Instead, it gradually fills over the first few hours to days, reaching its full size within about 24 to 72 hours.
One telltale feature: a cephalohematoma stays confined to a single skull bone. It will not cross the midline of the head or spread past the natural seams (suture lines) between skull bones. This is because the periosteum is firmly attached at those seams, creating a natural boundary that traps the blood collection in place.
Risk Factors for Cephalohematoma
Several delivery-related factors raise the likelihood:
- Assisted delivery using vacuum extraction or forceps
- Prolonged or difficult labor
- Larger-than-average baby weighing more than 8 pounds 13 ounces
- Multiple babies (twins, triplets, or more)
- Epidural pain relief during childbirth, which may be associated with longer pushing stages
Instrument-assisted deliveries carry the highest risk because vacuum cups and forceps apply direct pressure to the baby’s scalp, making those small blood vessels more likely to tear.
How It Differs From Other Scalp Bumps
Not every bump on a newborn’s head is a cephalohematoma. Two other types of scalp swelling look similar but behave very differently.
Caput Succedaneum
This is simple fluid swelling in the soft tissue of the scalp, sitting above the periosteum rather than beneath it. Because it’s in a more superficial layer, it freely crosses suture lines and can spread across the top of the head. It’s visible at birth and typically disappears within 48 hours. It’s harmless and extremely common after vaginal delivery.
Subgaleal Hemorrhage
This is a more serious condition where bleeding occurs in a different layer, between the periosteum and the flat tendon-like tissue that covers the skull. Unlike a cephalohematoma, a subgaleal hemorrhage can cross suture lines and spread widely across the scalp because that space has no bony boundaries to contain it. It can also appear at birth or within hours. This type of bleeding carries a high mortality risk and may be associated with seizures, skull fractures, and low muscle tone. It requires immediate medical attention.
The key distinction parents can watch for: a cephalohematoma stays on one bone and appears gradually. A bump that is spreading, present immediately, or making the baby appear unwell is a different situation entirely.
Healing Timeline
Most cephalohematomas resolve on their own within two weeks to six months. In the early days, the bump feels soft and fluctuant, almost like a water balloon under the skin. As the body begins reabsorbing the blood, the edges of the bump may start to harden first, which can make the center feel like a dip or crater. This is normal. It happens because the body lays down a thin shell of calcium around the edges of the blood collection as part of the healing process. Over time, the entire area flattens out and the skull contour returns to normal.
During the reabsorption phase, the baby’s body is breaking down a pool of trapped red blood cells. As those cells break apart, they release bilirubin, the same yellow pigment that causes newborn jaundice. A large cephalohematoma can release enough bilirubin to push levels higher than normal, so your baby’s care team will monitor for signs of jaundice, particularly yellowing of the skin or eyes, in the days and weeks after birth.
Treatment and Management
The standard approach is observation. The bump is left alone and allowed to reabsorb naturally. Draining it with a needle (aspiration) is generally avoided because puncturing the collection introduces a risk of infection into a space that would otherwise heal safely on its own. Rubbing or massaging the bump can also worsen the bleeding and should be avoided.
In rare cases, the calcium shell that forms around the edges doesn’t fully dissolve, and the bump hardens permanently. This is called a calcified cephalohematoma. A 25-year review at one institution found 81 children with calcified cephalohematomas, and 33 of them needed surgery to correct the resulting skull deformity. This is uncommon, though, and surgery is only considered when the hardened bump creates a noticeable cosmetic issue that won’t improve on its own.
What to Watch For
While most cephalohematomas are harmless, a few signs suggest something more is going on. Contact your baby’s provider if the bump is growing rapidly after the first few days, if the skin over it becomes red or warm to the touch (which could signal infection), or if your baby seems unusually sleepy, is feeding poorly, or looks increasingly yellow. These could indicate complications like infection, anemia from blood loss, or jaundice that needs treatment.
A cephalohematoma that remains soft and stable, even if it looks large, is generally following the expected course. The hardening at the edges that happens over the first few weeks is part of normal healing, not a warning sign.