Your newborn infant's immune system is still immature when you bring her home from the hospital. Unless you keep everyone who may be sick away from her, she is going to be exposed to illnesses and develop colds or gastrointestinal illnesses. If you are a first-time parent, you may be fearful that every unusual symptom your little one develops is a sure sign of a major condition. Familiarize yourself with signs that your newborn may be sick to help determine when a call to the doctor is in order.
Trust your parental instinct. The symptoms your newborn is displaying should be clear enough to tell you something is not right with the baby -- he may be more fussy than usual or he may have trouble getting to sleep. Call the pediatrician's office for advice.
Take the baby's temperature. If she has developed a cold, she may develop a slight fever. If your newborn's rectal temperature registers 100.4 degrees Fahrenheit or higher, however, call your doctor right away as it could indicate a serious illness, according to FamilyDoctor.org.
Monitor your baby's bowel movements. If they become more frequent or watery, he may have developed a gastrointestinal illness. If you notice runny stools or diarrhea, your baby may also have stomach cramps. Consult a physician for advice.
Call your doctor if the baby vomits -- this is different from her usual "spit-up," which is a smaller amount of formula or breast milk coming up from her stomach. If she vomits frequently during an illness, she is at risk of dehydration. She can also aspirate or inhale her vomit and choke.
Check your baby's soft spot at the top of his head to see if it is sunken in and note if he isn't urinating as much as usual. These are signs of dehydration which requires medical care. Other signs of illness and dehydration include lack of tears when he cries, lethargy, pale skin, a dry, tacky mouth and strong-smelling urine.
Look for nasal secretions that change to a thick, yellowish or greenish color in a day or two. The baby may have developed a cold or respiratory infection or she may be allergic to her formula if you bottle-feed her.
Listen for coughing, wheezing or croupy sounds from your newborn. Because his respiratory tract is irritated, he may begin coughing. Wheezing sounds -- a high-pitched whistling noise you can hear when he tries to breathe out -- develop when his airway is narrowed by too much mucus. Wheezing is another clue of illness. The croupy breathing sounds very noisy. When he coughs, it sounds like the bark of a seal. If you detect this particular symptom, call the doctor right away.
Make note of your baby's skin. If she develops an unusual rash, she could be developing a bacterial or viral infection. She may also be displaying an allergic reaction to her formula or another substance in her immediate environment.
Look at any changes in your baby's skin and eye color. If the whites of his eyes turn yellow or pink, this is a sign of illness. His skin may become flushed, especially if he has a fever. If he becomes pale, this is another sign of illness.