Table 1

Description of continuous variables in all the 83 preterm newborn studied

Mean (SD)Median (IQ25–IQ75)
Anthropometric variables
Weeks of gestation31 (29–33)
Birth weight (kg)1.52 (0.53)
Birth weight z-score0.4 (−0.9–0.5)
Birth length (cm)41 (43–36.5)
Birth length z-score−0.03 (1.28)
Head circumference at birth (cm)29 (27–31)
Head circumference at birth z-score0.2 (−0.5–0.9)
Nutritional development variables
Weight gain (g/day)19.61 (7.17)
ZWD–ZWB−1.03 (0.70)
Weight at discharge (kg)2.36 (2.07–2.68)
ZWD1.22 (1.18)
Length at discharge (cm)46 (44–48)
Length at discharge z-score−0.89 (1.44)
Increase in length (cm/week)1 (0.60–1.20)
Head circumference at discharge (cm)32 (31–33)
Head circumference at discharge z-score−0.52 (1.13)
Increase in head circumference (cm/week)0.6 (0.5–0.87)
Nutritional variables
Parenteral nutrition (days)4 (0–9)
Iron intake (mg/kg/day)4.43 (2.21)
Protein intake (g/kg/day)3.35 (0.89)
Zinc intake (mg/kg/day)1.30 (0.91–1.52)
  • Variables with normal distributions are represented as means (SD), while variables with non-normal distributions are shown as medians (IQ25–IQ75). Kolgorov-Smirnov with Lilliefors correction test to study normality.

  • ZWD-ZWB, z-score of weight at discharge minus the z-score of weight at birth.