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Postnatal development of urea synthesis capacity in preterm infants with intrauterine growth retardation

G Boehm1, B Teichmann, K Jung

  • 1Center for Infant Nutrition to Prevent Illnesses in Adult Life, Milan, Italy. milupa.research@t-online.de

Biology of the Neonate
|July 10, 1998
PubMed

Insights

Severe intrauterine growth retardation (IUGR) impairs urea synthesis in preterm infants. Infants with IUGR who did not achieve catch-up growth showed persistently higher urea synthesis rates, unlike those who did catch up.

Area of Science:

  • Neonatal physiology and metabolism
  • Developmental pediatrics
  • Nutritional science

Background:

  • The urea-synthesizing capacity is crucial for nitrogen excretion in neonates.
  • Intrauterine growth retardation (IUGR) can affect postnatal development and metabolic function.
  • Preterm infants, especially those with IUGR, may have altered metabolic pathways.

Purpose of the Study:

  • To investigate the postnatal development of urea-synthesizing capacity in preterm infants with IUGR.
  • To compare urea synthesis between infants with and without IUGR.
  • To examine the impact of catch-up growth on urea synthesis in preterm infants with IUGR.

Main Methods:

  • Studied 21 preterm infants with IUGR and 12 controls.
  • Estimated urea-synthesizing capacity using the ratio (Q) of 15N abundance in ammonia and urea in urine.
  • Measurements were taken during the first week of adequate protein/energy intake and before hospital discharge.

Main Results:

  • Infants with IUGR and no catch-up growth had significantly higher Q values on study day 1 compared to controls and IUGR infants with catch-up growth.
  • Q values decreased significantly in IUGR infants with catch-up growth between study days, reaching control levels.
  • Q values in IUGR infants without catch-up growth remained elevated and did not change significantly, correlating with the degree of IUGR.

Conclusions:

  • Urea-synthesizing capacity increases during early postnatal life in preterm infants.
  • Severe IUGR can impair the normal development of urea synthesis.
  • Interpreting metabolic studies using urea in preterm infants with severe IUGR requires caution.

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