2025 – PAGE 170 – NEONATOLOGY

PREMATURE INFANTS

CLASSIFICATION

• • Preterm = < 37 weeks gestation
  • Late preterm infants = 34 weeks to 36 + 6/7 weeks
  • Full term = 37 to 41 + 6/7 weeks
  • Postterm = 42 weeks and beyond

ESTIMATING GESTATIONAL AGE BY PHYSICAL EXAM

For the pediatric board exam, you should be able to properly identify a premature child (less than 37 weeks) by estimating gestational age through a physical exam!

SHORTCUTS: At a gestational age of < 35 weeks, hair is all over the body ± face. There are 0–3 creases on the sole and none at the heel. Ear cartilage still slowly unfolds. There is NO BREAST BUD.

• In males, there are NO PALPABLE TESTES and very few rugae.
• In females, there is a PROMINENT CLITORIS, but the labia majora is small.

SHORTCUT: If a vignette mentions the presence of any of the following, it is likely that the child is FULL TERM:

• MANY CREASES ON SOLES
• BREAST BUDS
• PALPABLE TESTES
• MANY RUGAE
• SPRINGY EAR CARTILAGE

CALCULATING GESTATIONAL AGE

Although a child is considered full term at 37 weeks gestation, for patients who are considered premature, use 40 WEEKS to calculate corrected gestational age. For example, if a child was born 8 weeks ago at 36 weeks gestation, s/he should be meeting the developmental milestones of a 4-week-old child (corrected gestational age is 4 weeks). Corrections are no longer needed after 2 years.

PREMATURE INFANT NUTRITION

Nutritional requirements for premature infants include high amounts of calcium, phosphorus, Vitamin D (due to a lack of bile salts needed to absorb the fat-soluble vitamins), and Vitamin E. Therefore, preemies are at much higher risk for developing Rickets. Vitamin E supplementation can help prevent hemolytic anemia.

• CALORIC REQUIREMENT: 120 kcal/kg/day. Use 24 kcal/oz premature formula rather than the usual 20 kcal/oz formula.
• CARBOHYDRATES: Glucose polymers are preferred over Lactose.
• FATS: Intake should consist of at least 50% Medium Chain Triglycerides (MCTs). This is because preemies lack certain lipases needed for fat digestion.
• PROTEIN: 3.5 grams/kg/day
• Catch-up growth happens in the first 2 years, so the patient should be at a normal weight by 2 years of age.