Table 2. Clinical outcomes, including retinopathy of prematurity stages by gestational age, before and after the implementation of the Koala Project.

	Age group (weeks)				p-value
	<28 n (%)	28 a 31 n (%)	32 a 33 n (%)	34 a 36 n (%)
Necrotizing enterocolitis
Before	1 (25)	0	0	1 (4.3)	0.407
After	0 (0)	1 (8.3)	2 (13.3)	1 (11.1)
Bronchopulmonary dysplasia
Before	3 (75)	3 (16.7)	0	0	<0.001
After	2 (33.3)	1 (8.3)	1 (6.7)	0
Retinopathy of prematurity stages
Before
1	2 (50)	0)	0	0	<0.001
2	1 (25)	15 (83.3)	9 (69.2)	7 (30.4)
3	0	0	0	15 (65.2)
4	1 (25)	3 (16.7)	4 (30.8)	1 (4.3)
After
1	3 (50)	5 (41.7)	1 (6.7)	0	0.002
2	0	4 (33.3)	4 (26.7)	2 (22.2)
3	0	0 (0)	3 (20)	6 (66.7)
4	3 (50)	3 (25)	7 (46.7)	1 (11.1)
Deaths
Before	1 (25)	1 (5.6)	1 (7.7)	1 (4.3)	0.951
After	0	0	0	0

n: absolute frequency; %: relative frequency percentage. Likelihood Ratio Test from the log-linear model for the conditional independence hypothesis.