Table 2 Infants’ characteristics and short term outcomes by plurality and mode of conception (n = 2934)

Gender, females

944

(45.5)

27

(61.4)

0.036

255

(47.0)

128

(47.4)

0.923

SGA

217

(10.5)

6

(13.6)

0.498

41

(7.6)

16

(6.0)

0.393

Malformations

 Lethal

2

(0.1)

0

0

0

0.265

 Acutely life-threatening

35

(1.8)

0

0.790

4

(0.8)

0

 Non acutely life-threatening

105

(5.3)

3

(7.1)

23

(4.4)

8

(3.1)

Apgar score <7/ intubated at 5 m’

965

(47.1)

23

(52.3)

0.500

218

(40.7)

101

(38.1)

0.474

CRIB score

>2

773

(41.4)

17

(41.5)

0.758

158

(32.8)

77

(32.8)

0.777

not attributed

213

(13.2)

3

(6.8)

61

(11.2)

35

(13.0)

Any surfactant

1164

(57.3)

29

(69.0)

0.129

300

(56.7)

139

(53.0)

0.330

nCPAP

1462

(72.3)

33

(78.6)

0.368

357

(68.3)

167

(64.2)

0.259

Mechanical ventilation

1272

(62.7)

31

(72.1)

0.205

316

(60.3)

138

(52.5)

0.036

PDA

798

(42.5)

20

(55.6)

0.116

243

(50.7)

101

(42.8)

0.046

NEC

69

(3.5)

0

0.226

20

(3.8)

6

(2.4)

0.286

Sepsis/meningitis

442

(21.8)

7

(16.7)

0.425

106

(20.0)

48

(18.4)

0.591

IVH grade 3 or 4

166

(8.5)

6

(14.3)

0.188

52

(10.3)

25

(9.9)

0.865

c-PVL

99

(5.1)

0

0.142

32

(6.23)

12

(4.8)

0.393

ROP stage ≥3

79

(4.3)

1

(2.9)

0.676

17

(3.7)

5

(2.1)

0.280

BPD

219

(12.7)

6

(17.1)

0.433

44

(10.1)

9

(4.2)

0.010

Death before discharge

364

(17.6)

9

(20.9)

0.566

110

(20.4)

52

(19.3)

0.709

Survival without major morbidities¹

1356

(65.4)

26

(60.5)

0.500

363

(67.2)

191

(70.7)

0.310

Any breast feeding at discharge

1001

(59.8)

23

(74.2)

0.105

255

(61.3)

135

(63.4)

0.611

Lenght of stay, survivors Days, mean (sd)

64.6

(34.3)

61.9

(31.2)

0.653 ²

60.2

(33.2)

54.5

(27.7)

0.031 ²