Neonatal weight gain and nutrition
Feeding and growing is one of the most important tasks of small babies in the hospital.
It is important that premature babies receive the right nutrition so they reach a weight similar to that they would have gained if they were still inside the womb.
Newborn nutrition; Nutritional needs -- premature infants
Babies born less than 37 weeks in the womb (premature) have different nutritional needs than babies born at full term (38 - 42 weeks).
Premature babies will often stay in the neonatal intensive care unit, where they will be carefully monitored to make sure they are getting the right balance of fluids, minerals such as sodium and potassium (electrolytes), and nutrition until their bodies mature.
Careful temperature control, often in with an incubator or special warmer, helps to reduce excess calorie needs. Humidified (moistened) air helps maintain body temperature and avoid fluid loss.
Babies born before 34 weeks often can't feed from a bottle or breast because they have trouble coordinating sucking, breathing, and swallowing. Also, newborns with breathing problems, very low oxygen levels, gagging, circulatory problems, blood infection, or other illnesses might not be able to feed through a nipple (orally).
Neonates who are very small or sick may need to get nutrition and fluids through a vein (intravenously). As they get bigger and stronger, they can start to receive breast milk or formula through a small tube inserted through the nose or mouth into the stomach (gavage feeding). Premature babies are fed very slowly to reduce the risk of getting an intestinal infection called necrotizing enterocolitis.
Babies who are less premature (born at or after 34 weeks gestation) often can be fed from a bottle or the mother's breast. Sometimes it's easier for a premature baby to drink pumped breast milk from a bottle with a large hole in the nipple than from the breast.
Preterm babies lose more water through the skin or respiratory tract than babies born at full term. Also, the kidneys in a preterm baby have not matured enough to adjust for too much or too little water in the body. These babies can become dehydrated or overhydrated. At the hospital, health care workers will check premature babies' urine to make sure that their fluid intake and urine output are balanced. Blood tests are also done to monitor electrolyte levels.
Breast milk is the recommended diet for most infants, when possible, even those born early and at very low birth weight. Research suggests that breast milk protects babies against infections and sudden infant death syndrome (SIDS).
If it is not possible for the baby to take breast milk, special preterm formulas can be used. These formulas have a higher amount of fat and protein to meet the special growth needs of premature babies. Once babies reach 34 - 36 weeks gestation, they can be switched to regular formula.
Most neonates need 100 - 120 calories per kilogram of weight per day (cal/kg/d) in order to grow properly. Infants who have health problems may need extra nutrition -- up to 160 - 180 cal/kg/d.
Premature babies have not been in the womb long enough to store up the nutrients they need and must usually take supplements. Babies who are breast-fed may need a supplement called human milk fortifier added to the breast milk. This supplement contains the extra protein, calories, iron, calcium, and vitamins that premature babies need. Those fed formula may need to take added supplements of certain nutrients, including vitamins A, C, and D, and folic acid. Some infants who were born prematurely will need to continue taking nutritional supplements after they leave the hospital.
In the NICU, babies are weighed every day. It's normal for babies to lose weight in the first few days of life. Most of this loss is water weight. Most premature infants should start gaining weight within a few days of birth.
The desired weight gain depends on the baby’s size, gestational age, and health. It might be as little as 5 grams a day for a tiny baby at 24 weeks, or 20 grams a day for a larger baby at 33 weeks.
One rule of thumb that sometimes applies during part of the hospital stay is that a baby should gain a quarter of an ounce each day for every pound he or she weighs. (This is equal to 15 grams per kilogram). Premature babies aren't released from the hospital until they are gaining weight steadily and have reached about 2 kilograms in weight.
After each feeding, babies should seem satisfied. They should have 1 - 6 stools and 6 - 8 wet diapers each day. Watery or bloody stools or regular vomiting could signal a problem.
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Clark RH, et al. Nutrition in the neonatal intensive care unit: how do we reduce the incidence of extrauterine growth restriction? Journal of Perinatology. June 2003:23:337-44.
Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: Saunders; 2004.
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Reviewed By: Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor of Pediatrics, NYU School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. Previously reviewed by Alan Greene, MD, FAAP, Department of Pediatrics, Stanford University School of Medicine, Lucile Packard Children's Hospital; Chief MedicalOfficer, A.D.A.M., Inc.