The Study of Transplacental Transfer of Immunoglobulin G in Premature Infants

ABSTRACT

PURPOSE: Premature infants have low serum immunoglobulin G (IgG) levels because IgG is transplacentally acquired, primarily after 32-34 weeks of gestational age. We studied the transplacental transfer of serum IgG in preterm infants. METHODS: The IgG levels in the sera were measured by radial immunodiffusion method (Behring nephelometer, Germany). RESULTS: There was a significant difference between IgG concentration and gestational age; the IgG concentration increased from 462.2 +/- 105.5mg/dL at less than 26 weeks of gestation to 1009.0 +/- 242.6mg/dL at 35 and 36 weeks of gestation with increasing gestational age (P<0.01). The linear relation between IgG concentration and birthweight; the IgG concentration in the sera of premature infants were increased from 588.3 +/- 136.4mg/dL at birthweight less than 1250g to 1149.3 +/- 287.8mg/dL at birthweight more than 2251g with increasing birth weight (P<0.05). CONCLUSION: The effects of gestational age and birthweight on the concentration of IgG at birth were highly interdependent and significant. These results suggest that IVIG administration is needed for nearly all premature infants with birthweight less than 1200g and gestational age less than 32 weeks.