Table 1 Comparison between Twin-H and Twin-L in weight (kg) and height (cm) and growth rates (%)

Birth

2.8 ± 0.5

2.0 ± 0.4

 < 0.001

50.0 (48.0,50.0)

47.0 (42.0,48.0)

 < 0.001

1 month

4.4 ± 0.7

3.6 ± 0.6

 < 0.001

54.3 ± 2.3

51.0 ± 3.0

 < 0.001

54.8 (37.6,72.4)

74.2 (57.9,105.9)

 < 0.001

12.4 ± 5.9

13.1 ± 5.4

0.482

3 months

6.5 ± 0.8

5.5 ± 0.8

 < 0.001

61.3 ± 2.4

58.7 ± 3.3

 < 0.001

51.5 ± 21.8

57.8 ± 24.7

0.086

13.0 ± 4.2

15.2 ± 4.5

0.006

6 months

8.3 ± 1.0

7.2 ± 1.0

 < 0.001

68.2 (67.0,69.0)

65.4 (63.5,67.0)

 < 0.001

25.3 (18.2,32.3)

28.6 (20.5,40.5)

0.013

10.5 (7.2,13.6)

10.0 (8.2,13.3)

0.596

8 months

9.3 ± 0.8

8.2 ± 1.0

 < 0.001

71.9 ± 3.0

69.2 ± 3.4

 < 0.001

12.6 ± 7.6

14.6 ± 9.4

0.072

5.8 (4.0,7.0)

5.9 (4.6,7.5)

0.456

12 months

10.3 ± 1.0

9.2 ± 1.0

 < 0.001

76.4 ± 2.6

74.2 ± 3.0

 < 0.001

11.2 ± 7.4

12.3 ± 6.0

0.381

6.2 ± 2.7

7.3 ± 2.6

0.012

18 months

11.5 ± 1.1

10.3 ± 1.1

 < 0.001

82.8 ± 2.8

79.7 ± 3.5

 < 0.001

12.3 ± 7.4

12.8 ± 7.5

0.635

8.5 ± 3.0

7.4 ± 3.2

0.115

24 months

12.8 ± 1.2

11.6 ± 1.3

 < 0.001

89.0 (87.0,90.0)

86.0 (85.0,88.0)

 < 0.001

11.5 ± 5.0

12.4 ± 5.9

0.351

6.7 ± 2.1

7.3 ± 2.4

0.309

30 months

13.9 ± 1.3

12.7 ± 1.4

 < 0.001

93.5 ± 3.2

90.3 ± 3.9

 < 0.001

8.0 ± 4.7

9.8 ± 5.3

0.035

5.7 ± 2.4

5.6 ± 2.2

0.838

36 months

15.1 ± 1.4

13.8 ± 1.5

 < 0.001

98.0 (96.0,100.0)

96.0 (93.5,98.0)

 < 0.001

8.8 ± 4.9

8.9 ± 5.3

0.911

5.2 (3.2,6.5)

5.3 (4.3,6.6)

0.092

48 months

17.1 ± 1.6

15.6 ± 1.8

 < 0.001

104.0 (102.0,107.0)

102.0 (99.0,104.0)

 < 0.001

13.6 ± 4.8

12.6 ± 6.9

0.432

6.8 (5.2,8.0)

6.1 (5.1,8.5)

0.879

60 months

19.1 ± 2.1

17.4 ± 2.2

 < 0.001

111.6 ± 4.6

108.7 ± 5.0

 < 0.001

11.7 ± 4.9

11.3 ± 5.4

0.735

6.5 (4.9,7.8)

6.5 (4.9,7.8)

0.798

72 months

21.5 ± 2.5

19.7 ± 2.3

 < 0.001

118.8 ± 5.0

115.2 ± 5.6

 < 0.001

11.6 (8.0,15.8)

12.6 (8.7,16.7)

0.848

6.5 ± 1.9

6.0 ± 1.9

0.009