Normal total plasma calcium in the newborn.

Area of Science:

• Neonatal physiology
• Pediatric endocrinology
• Biochemistry

Background:

• Plasma calcium levels in newborns are dynamic and lower than in adults.
• Cord blood calcium is higher than maternal, but drops significantly post-birth.
• These calcium drops are influenced by factors like feeding, starvation, and infant age.

Purpose of the Study:

• To define normal plasma calcium ranges in newborns during the first week of life.
• To understand the patterns and influencing factors of neonatal calcium levels.
• To provide clinically relevant data for identifying and managing neonatal hypocalcemia.

Main Methods:

• Review of existing literature on neonatal calcium levels and related diseases.
• Analysis of calcium concentrations in full-term, premature, and low birth weight infants.
• Utilizing ultramicrochemical analytical methods for precise calcium measurements.

Main Results:

• Newborns exhibit a precipitous drop in plasma calcium within 24 hours of birth, reaching a minimum around 48 hours.
• A potential third drop between days 4-7 is often preventable with adequate milk intake.
• Normal ranges: 1.75-3.00 mmol/l for full-term, 1.50-2.50 mmol/l for premature infants.
• Low birth weight infants show intermediate values.

Conclusions:

• Neonatal plasma calcium levels undergo significant, predictable changes in the first week.
• Understanding these normal ranges and influencing factors is critical for diagnosing conditions like neonatal tetany.
• Accurate analytical methods are essential for reliable neonatal calcium assessment.