How Long Do Late Preterm Infants Need Supplemental Feedings?

Patient Presentation
A 19 day old, former 35 1/7 week late preterm male infant came to clinic for his first appointment after he was discharged from the neonatal intensive care unit. He was breastfeeding every 2-2.5 hours for 10 minutes and then parents would syringe feed him breastmilk that was fortified to 24 kcal/ounce with premature infant powdered formula. He would take about 10 ml after most feeds. His weight gain had been averaging 15-20 grams/day before discharge, and since he had been home for the last 4 days it had been 10-15 grams/day . His mother noted that he still seemed quite sleepy but would appropriately arouse, eat and then fall back to sleep. “Since we’ve been home though, its probably closer to every 2.5 hours feeding than the 2 hours we were doing in the hospital,” she said. The past medical history showed a neonatal intensive care course where he received antibiotics for 48 hours as his mother was Group B streptococcus positive and had not been adequately treated with antibiotics before delivery. His laboratory values and cultures were negative and his antibiotics were then stopped. He had mild respiratory distress initially that was treated by nasal canula for 3 days. He also had poor feeding so he received parenteral nutrition for 6 days, transitioned to gavage feedings and then to full oral feeds.

The pertinent physical exam showed a small infant with normal vital signs. His birth weight had been 2.230 kg (10-50% on Fenton premature infant growth chart) and now was 2.544 kg (10%). His length was 48 cm (10%) and his head circumference was 34 cm (50%). He had an open, flat fontanelle without overriding sutures. He had some subcutaneous fat but was still somewhat thin. His examination was otherwise unremarkable. The diagnosis of a late preterm infant who was now feeding and growing was made. The pediatrician recommended that the family continue the current feeding regimen but to also try to feed the infant closer to every 2 hours. “We don’t want to tire him out, but if he eats closer to every 2 hours then he’ll get another 1-2 feedings a day and that is huge for him and his growth. I also would not limit the amount he takes by syringe. If he seems hungier you can give him more, but I would try to give him at least 10 ml,” he recommended.

The patient’s clinical course the following week showed him to be gaining 20 g/day. “We’ve been feeding him closer to every 2 hours, plus he seems to be eating better at the breast. He’s only taking about 5 mls after feedings,” described his mother. “He’s obviously growing and doing better. I’m glad to hear that he is breastfeeding better. He’s still not full-term yet so I’d continue to offer the fortified supplement,” said the pediatrician. Over the next 2 weeks, the infant started to breastfeed more vigorously and stopped taking the supplements. At 41 weeks adjusted age, he was 3.432 kg (10-50%), and was not taking any supplementation.

Premature infants have many problems to overcome because they just aren’t ready to live outside the uterine environment.
Late premature infants are defined as birth between 34 0/7 weeks and 36 6/7 weeks gestation. In the U.S. this gestational age accounts for ~70% of all preterm births or ~300,000 births/year. Late preterm infants can have delayed oral feeding skills and failure to thrive along with increased hospital readmissions. Breastfeeding can be difficult as infants can have poor coordination and poor tone, along with decreased lactation in the mother.

Learning Point
Weight gain lags behind intrauterine weight gain in premature infants including late preterm infants. The intrauterine growth is ~15 g/day at this age and in one study only 2% of preterm infants achieved this weight gain. Late preterm infants have increased energy, protein, calcium and phosphorous needs as this is the time that the fetus would be storing fat and minerals. It is also a time when brain growth and volume are markedly increased. Late preterm infants need additional nutritional supplementation. Therefore it is recommended that late preterm infants be breastfed with fortified human milk until at least 40 weeks postconceptional age. Human milk fortifier or special preterm discharge formula are recommended for use as the supplements as they contain additional calories, protein and minerals compared to standard infant formula. Preterm infants that are born earlier and weigh less, not surprisingly need supplemental nutrition for longer. For infants 25 grams/day) and reaches term weight (~3.25 kg). For formula fed infants, fortified formula with a premature infant formula at 22 kcal/ounce should be offered until the infant is 40 weeks postconceptional age and term weight. Then the infant can be transitioned to term formula at 20 kcal/ounce.

Questions for Further Discussion
1. What are indications for enteral or parenteral nutrition in preterm infants?
2. By what age should preterm infants be “caught-up” and following term infant growth patterns?
3. What nutritional supplementation do low birth weight or extremely low birth weight infants need?
4. What are some advantages of human donor breastmilk? They can be reviewed here

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Premature Babies and Child Nutrition.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Carlson SK, Segar JL. Nutritional Needs of the Late Preterm Infant.
The Iowa Perinatal Letter. 2014;32(2).

Gianni ML, Roggero P, Piemontese P, Is nutritional support needed in late preterm infants? BMC Pediatr. 2015 Nov 23;15:194.

Raaijmakers A, Allegaert K. Catch-Up Growth in Former Preterm Neonates: No Time to Waste. Nutrients. 2016 Dec 17;8(12). pii: E817.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa