Intrauterine Growth Restriction and Zinc Concentrations in Term Infants during the First Month of Life

Abstract

Objective: We analyzed the influence of IUGR on the concentrations of plasma (Znpl) and erythrocyte (Zne) zinc and on the ratios of Zne to Znpl (Zne:Znpl) and Zne to hemoglobin (Zne:Hb) in term infants during the first month of life.

Design: Cohort study.

Setting: Tertiary Care Neonatal Unit.

Subjects: Exclusively breastfed term newborns (n = 84) were divided into 3 groups: group I, without IUGR (n = 41), group II, with mild to moderate IUGR (n = 12), and group III, with severe IUGR (n = 31). IUGR was defined as birth weight under the 5th percentile of the Alexander et al curve and as a Kramer Index (KI; ratio of birth weight to estimated weight for each gestational age) <0.85. Severe IUGR was defined as a KI <0.75. Znpl, Zne, and Hb were measured at birth, 3 days, and 1 month of life.

Results: Znpl tended to decrease (P = 0.073), Zne and Zne:Znpl increased (P < 0.001), and Hb decreased (P < 0.001) during the first month of life. There was not Znpl, Zne and Zne:Znpl time by group interaction. Zne:Hb increased (P < 0.001) during the first month of life and was lower in Group II at 1 month of age. Differences between Groups I and II (P = 0.017); and Groups II and III at 1 month of age (P = 0.011) were detected.

Conclusions: Our results suggest that IUGR did not have association with erythrocyte zinc and Zne:Hb ratio at birth. However, neonatal nutrition could have influenced zinc incorporation during this period, through Zne increase.

• zinc
• fetal growth retardation
• infant
• newborn

We thank Nairo Massakazu Sumita, Director of Biochemistry Service of Central Laboratory of Hospital São Paulo (Clinics), who enabled the measures of zinc levels, Atleca Nunciata Lopes Alves, who measured all zinc levels, Marcos Antônio Gonçalves Munhos, Director of Hematology. Cytology and Genetic Service of Central Laboratory of Hospital São Paulo (Clinics), who enabled the measures of hemoglobin, Cláudio Leone and Ulysses Doria Filho, who helped us with the statistical analysis.