Table 2 Bivariate analyses related to characteristics of preterm newborns (Blocks 2, 3 and 4)

Gender, n(%)

0.485

 Female

61 (53.0)

25 (54.3)

36 (52.2)

 Male

54 (47.0)

21 (45.7)

33 (47.8)

APGAR 1^st minute, n(%)

0.017^b

  < 7

65 (56.5)

32 (69.6)

33 (47.8)

  ≥ 7

50 (43.5)

14 (30.4)

36 (52.2)

Gestational age at birth, n(%)

 < 0.001^b

  < 28 weeks

30 (26.1)

22 (47.8)

8 (11.6)

  ≥ 28 weeks

85 (73.9)

24 (52.2)

61 (88.4)

Weight at birth, n(%)

 < 0.001^b

  < 1,000 g

42 (36.5)

31 (67.4)

11 (15.9)

  ≥ 1,000 g

73 (63.5)

15 (32.6)

58 (84.1)

Clinical diagnosis, n(%)

 Jaundice

104 (90.4)

42 (91.3)

62 (89.9)

1.000

 Patent foramen ovale

75 (65.2)

29 (63.0)

46 (66.7)

0.419

 Sepsis

59 (51.3)

32 (69.6)

27 (39.1)

0.001^b

 Intraventricular hemorrhage

59 (51.3)

24 (52.2)

35 (50.7)

0.515

 Patent ductus arteriosus

55 (47.8)

25 (54.3)

30 (43.5)

0.170

 Bronchopulmonary dysplasia

37 (32.2)

22 (47.8)

15 (21.7)

0.003^b

 Retinopathy of prematurity

36 (31.3)

15 (32.6)

21 (30.4)

0.482

Support (Days), average ± SD

 Non-invasive mechanical ventilation

23 ± 17.2

22 ± 17.9

23 ± 16.7

0.753

 Invasive mechanical ventilation

16 ± 18.6

25 ± 21.8

10 ± 12.9

 < 0.001^b

Physiotherapy (Days)

 Average ± SD

49 ± 8.3

49 ± 6.7

49 ± 9.3

0.590

Medications (Days), average ± SD

 Antibiotics

23 ± 13.1

26 ± 12.5

21 ± 13.2

0.040^b

 Diuretics

11 ± 13.9

16 ± 15.8

7 ± 11.1

 < 0.001^b

 Methylxanthines

38 ± 14.2

46 ± 10.8

33 ± 13.9

 < 0.001^b

 Corticosteroids

3 ± 6.0

4 ± 6.7

2 ± 5.5

0.216

 Antiulceratives

3 ± 7.7

2 ± 4.2

4 ± 9.3

0.203

 Sedatives

9 ± 14.9

12 ± 15.3

8 ± 14.5

0.143

Nutritional status at term, n(%)

0.013^b

 Score Z ≤ -3SD

18 (15,7)

12 (26,1)

6 (8,7)

 Score Z > -3SD

97 (84,3)

34 (73,9)

63 (91,3)

Parenteral nutritional therapy, n(%)

0.017^b

  ≥ 14 days

73 (63.5)

35 (76.1)

38 (55.1)

  < 14 days

42 (36.5)

11 (23.9)

31 (44.9)

Trophic enteral feeding, n(%)

0.255

  ≥ 7 days

47 (40.9)

21 (45.7)

26 (37.7)

  < 7 days

68 (59.1)

25 (54.3)

43 (62.3)

Full enteral feeding, n(%)

0.001^b

  ≥ 14 days

55 (47.8)

13 (28.3)

42 (60.9)

  < 14 days

60 (52.2)

33 (71.7)

27 (39.1)

Pasteurized fresh human milk, average ± SD

 Total acidity (ºDornic)

3.8 ± 0.58

3.91 ± 0.55

3.77 ± 0.59

0.191

 Acidity in the first week

0.025^b

   ≥ 4 ºDornic, n (%)

39 (33.9)

21 (45.7)

18 (26.1)

   < 4 ºDornic, n (%)

76 (66.1)

25 (54.3)

51 (73.9)

Nutrient formula (FM85)

0.202

 No

41 (35.7)

19 (41.3)

22 (31.9)

 Yes

74 (64.3)

27 (58.7)

47 (68.1)

Supplementation, n(%)

 Tricalcium phosphate

84 (73.0)

43 (93.5)

41 (59.4)

 < 0.001^b

 Chelated zinc

44 (38.3)

13 (28.3)

31 (44.9)

0.053

 Vitamin D

114 (99.1)

45 (97.8)

69 (100)

0.400

Nutritional supply, average ± SD

 Total energy value (kcal/kg)

88.9 ± 20.8

84.1 ± 9.3

92.3 ± 25.4

0.013^b

 Protein (g/kg)

2.9 ± 0.3

2.92 ± 0.34

2.94 ± 0.27

0.629

 Calcium (mg/kg)

169.9 ± 43.9

182.7 ± 47.5

161.5 ± 39.5

0.013^b

 Phosphorus (mg/kg)

89.4 ± 28.4

98.3 ± 31.3

83.5 ± 24.8

0.008^b

 Zinc (mcg/kg)

659 ± 348

554 ± 326

729 ± 347

0.010^b

 Vitamin D (UI/dia)

485 ± 176

410 ± 160

536 ± 169

 < 0.001^b

 Average calcium/phosphorus ratio

1.95 ± 0.25

1.92 ± 0.25

1.96 ± 0.25

0.367