Maternal and perinatal predictors of newborn iron status.

Aim: To describe iron status at birth in a population sample of children.
Method: Cord blood samples were obtained at birth from 131 infants enrolled in the cohort study Growing Up in New Zealand. Cord blood serum ferritin (SF) and haemoglobin (Hb) concentrations were measured and associations of SF and Hb with maternal and birth characteristics were determined.
Results: Demographics were comparable to the larger cohort, except for having a higher pre-pregnancy body mass index (26.9 vs. 25.4 kg/m2, P=0.005), lower frequency of cigarette smoking during pregnancy (2% vs. 11%, P=0.0004), and smaller proportion with birth-weight <2500 g (0% vs. 5%, P=0.03). Median (interquartile range) SF was 135 (88-180) mcg/L and mean (plus or minus SD) Hb was 160 plus or minus 17 g/L. Eight newborns (7%) had cord SF levels indicative of iron deficiency (SF <35 mcg/L), two newborns were anaemic (Hb <130 g/L) and none had iron deficiency anaemia. Median SF was lower in newborns whose mothers consumed greater than or equal to 3 servings of milk/day during the pregnancy (131 vs. 151 mcg/L, P=0.04). No other associations with SF or Hb were observed.
Conclusion: Iron deficiency is present in 7% of newborns in New Zealand. Newborns whose mothers consumed more milk during pregnancy had a lower median SF concentration.