The idea that you must keep a baby awake after a head injury to prevent a coma is actually an old wive's tale. However, keeping your infant awake immediately after the head injury is important because it allows you to observe your baby's behavior, watching for signs of a "shake-up" in the brain, called a concussion, or bleeding inside the brain, called a hematoma. Call your doctor to ensure your baby does not need immediate care before beginning observation at home.
If your doctor does not recommend emergency care, he will likely ask you to keep your baby awake for one hour for observation. How your infant acts for the next hour usually tells the doctor more about your baby's condition than reporting how the injury occurred. If the head injury occurred close to nap time or bedtime, you might find it hard to keep your baby awake for an hour. If the doctor says it's OK for your baby to sleep in the first hour, try waking her 20 minutes after she's asleep. If she awakens as she normally would, let her go back to sleep. Call the doctor if your baby does not awaken normally.
After that first hour, let your baby sleep as she desires. Going to sleep is normal after a trauma. Continue to monitor your baby, waking her after two hours. Call the doctor immediately if your baby has trouble waking, or has any change in color or change in breathing. Irregular breathing, however, is normal for newborns. If you notice one limb on just one side of the body twitching, contact the doctor. Follow your doctor's advice on whether you need to continue to wake your baby every two hours.
Symptoms of a problem do not always appear immediately. These warning signs may appear within the first hour after the injury or not until three days later. Call the doctor if at any time in the next three days your infant loses consciousness, vomits three or more times, cries inconsolably for over an hour, or has any eye problems, such as crossed eyes, rolling eyes, or if one pupil appears larger than the other. If your baby is already crawling or walking, bumping into objects or losing balance also indicate a problem.
Most head injuries -- even ones that produce a goose-egg sized bump -- only injure the scalp and not the brain. Bleeding and crying are often normal after a bonk on the head. In fact, crying immediately after the injury is a good sign because it indicates your child hasn't lost consciousness. Coughing and gagging, as well as vomiting one two times are also normal reactions. Apply ice to the head, and for bleeding, apply pressure with a clean cloth. Trust your instincts and call the doctor if you have any concerns.