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

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.