Feeding babies in the NICU is quite different from feeding healthy babies. When babies are sick or premature, they are often not well enough to breastfeed or take a bottle. Premature babies may not be able to suck effectively, or their gastrointestinal tracts may not be mature enough to digest feedings. Babies who are medically unstable are often unable to take regular feedings. Babies with umbilical catheters and those who need help breathing, such as with a mechanical ventilator, may not be able to be fed because of the risk of complications such as aspiration (breathing food into the lungs).
Many babies in the NICU receive essential fluids and electrolytes through a tube in a vein called an IV. Some babies may need a special preparation called parenteral hyperalimentation, which contains nutrients they need until they are able to take milk feedings.
The contents of IV fluids and hyperalimentation are carefully calculated for each baby. Calories, protein, fats, and electrolytes including sodium, potassium, chloride, magnesium, and calcium are all important components. Babies need calories, protein, and fats for adequate growth and development. Fluids, electrolytes, and vitamins are necessary for proper functioning of the body's systems.
Blood tests help determine how much of each component a baby needs and the amount of each nutrient can be increased or decreased accordingly. Daily weights and keeping track of a baby's urine output also help monitor fluid needs.
Some babies have too much or too little of certain electrolytes or other components in the blood. As a result, some of the common problems include the following:
Hypernatremia. High amounts of sodium (salt) in the blood.
Hyperkalemia. High amounts of potassium in the blood; can be diagnosed by blood test, or by changes in the baby's heart rate pattern.
Hyperglycemia. High amounts of glucose (sugar) in the blood; diagnosed by blood tests, often done by heel stick; some babies may need insulin to control high glucose levels.
Hypoglycemia. Low blood sugar; usually treated with IV fluids containing dextrose (another form of sugar).
Hypocalcemia. Low calcium levels in the blood; usually treated with calcium in IV fluids.
Once your baby's condition is stable, readiness for milk feedings is checked.
Babies need to:
Show signs of sucking
Have active bowel sounds
Have passed meconium stools (baby's first bowel movements)
Have no signs of abdominal distention or infection
Most babies older than 28 weeks gestation have digestive tracts mature enough for milk feedings. Once your baby is taking milk feedings well and is gaining weight, intravenous (IV) fluids and hyperalimentation can be decreased.
Sick babies may not be strong enough to suck effectively. Premature babies may not be physically mature enough to coordinate sucking, swallowing, and breathing, or they may be too weak to suck for long periods of time. Special pacifiers designed for premature babies are sometimes used to teach them how to suck properly before they begin to breastfeed or bottle feed.
The following are some ways babies may be fed in the NICU:
Gavage or tube feedings. Premature babies, especially those younger than 32 to 34 weeks gestation, often cannot be fed from the breast or bottle. Gavage or tube feedings may be needed until the baby learns to suck effectively. For gavage feedings, a small flexible tube is placed into a baby's nostril or mouth and passed down into the stomach. The tube is sometimes removed, but may be left in place if feedings are frequent.
At first, tiny amounts of breast milk or formula are given through the feeding tube. Because of their small stomach size, very tiny babies may be fed using a pump that slowly delivers the milk in small amounts. As the babies grow, they are able to gradually take larger amounts at each feeding.
Before each tube feeding, a baby is checked for residual, the amount of milk in the stomach left over from the last feeding. If the amount of residual is too high, it may mean the baby is not digesting food well.
Nipple feedings. Feeding from breast or bottle can begin as soon as babies are stable and are able to suck effectively. Your baby may begin nipple feedings while still being tube fed. Even if a baby is able to nipple feed, it can be tiring. As your baby increases the amount he or she can take by nipple, the amount in the tube feedings can be decreased.
A mother's breast milk is the preferred milk for all babies, even the most premature babies. Breast milk contains all the nutrients needed for growth and development. Although commercial milk formulas are designed to be close to breast milk, most are based on cow's milk. The fats in breast milk are more easily digested. Formula is digested more slowly than breast milk and may not be as well tolerated. In addition, breast milk contains antibodies from the mother to help protect babies from infection, something commercial formulas do not have. This protection is especially important when babies are sick or premature and have higher chances of developing an infection.
Very premature babies may need human milk fortifiers added to breast milk to meet their increased needs for protein, calcium, and phosphorus. Even if your baby cannot breastfeed, you can pump your breast milk and it can be stored for gavage or nipple feedings. Depending on the amount of milk needed for feedings, formula may need to be added to breast milk.
Certified lactation consultants (IBCLC) are nurses or other health care providers who are specially trained to help women with breastfeeding. In the NICU, these professionals can instruct you in the proper techniques for nursing your baby. They can also teach you about pumping and storing your breast milk for your baby.