study

year

sample size

intervention measure

outcome indicator

IG

CG

IG

CG

frequency

F. T. Ji [12]

2016

28

27

Oral drip of colostrum

Saline drip

Once every 4 h, 0.2 ml each time, for seven days

A, B

X. J. Zhao [13]

2017

20

20

Oral drip of colostrum

Saline drip

Once every 4 h, 0.2 ml each time, for seven days

A

C. Y. Chen [14]

2018

46

46

Oral drip of colostrum

Saline drip

Once every 4 h, 0.2 ml each time, for seven days

A, B, C, D

S. X. Cao [15]

2018

20

20

Colostrum oral smear

Sterile water smear

Once every 3 h

B, E

Once every 6 h

L. F. Chen [16]

2017

30

30

Colostrum oral smear

Normal saline smear

Once every 3 h, for two weeks

B, C, D, E

Y. X. Zhang [9]

2017

27

28

Oral drip of colostrum

Saline drip

Once every 4 h, 0.2 ml each time, For seven days

C, E, G, H

Glass K. [11]

2017

17

13

Oral drip of colostrum

Sterile drop injection

Once every 3 h, 0.2 ml each time

C, E, G, H