Serum alpha fetoprotein (AFP) levels in normal infants

Area of Science:

• Pediatrics
• Biochemistry
• Neonatology

Background:

• Serum alpha-fetoprotein (AFP) is a protein primarily produced during fetal development.
• Understanding AFP levels in infants is crucial for assessing normal growth and development.

Purpose of the Study:

• To establish normal serum alpha-fetoprotein (AFP) levels in infants at various postnatal ages.
• To determine the degradation half-lives of AFP in infants.
• To investigate the persistence of AFP synthesis after birth.

Main Methods:

• Serum AFP levels were monitored in 32 normal infants from birth to 4 months.
• Additional measurements were taken from 116 infants with normal liver enzymes and 10 preterm infants.
• Data were combined to establish age-specific normal AFP ranges.

Main Results:

• Serum AFP levels decreased rapidly after birth.
• Normal infant AFP levels approached adult levels around 8 months of age.
• Estimated AFP degradation half-lives were 5.5 days (birth-2 wk), 11 days (2 wk-2 mo), and 33 days (2-4 mo).

Conclusions:

• Postnatal AFP levels decline significantly, with adult levels reached by 8 months.
• AFP degradation follows age-dependent half-lives.
• Evidence suggests continued, albeit decreasing, AFP synthesis after birth.