Moms dread that wake-up call in the middle of the night that signals illness in their child. Whether it's a fever, vomiting or something else, a nighttime illness can be scary. But not all of them warrant a call to the doctor or a visit to the emergency room. A good pediatrician will consider it part of her job to offer after-hours advice - pediatricians should expect worried parents to call at all hours. In fact, many say they worry about those parents who never call. If you're awakened by your child's cry - and it's "that" cry, the one that alarms you - assess a few things before picking up the phone or rushing to the ER. First, is your child feverish? Take his temperature, and if a newborn has a temperature of 100.4 or higher, then it's time to call. If the baby older and has a rectal temperature of 104 degrees or higher, then call.