Group

N

BPD

ROP

(≥level 2)

IVH (≥level 3)

NEC

(≥phase)

PDA

In total

Combination group

30

2 (6.67)

4 (13.33)

2 (6.67)

2 (6.67)

3 (10.00)

13 (43.33)

PICC group

30

5 (16.67)

6 (20.00)

4 (13.33)

5 (16.67)

5 (16.67)

21 (70.00)

t

1.4555

0.4800

0.7407

1.4555

0.5769

4.3439

p

0.2276

0.4884

0.3894

0.2276

0.4475

0.0371