Table 1 Parental and preterm infants characteristics (n = 500)

Maternal Age

18 ~ 25

35

7.0

(mean = 30.41)

26 ~ 30

172

34.4

31 ~ 34

243

48.6

≥35

50

10.0

Maternal educational level

Primary studies

15

3.0

Secondary studies

49

9.8

Undergraduate studies

338

67.6

Postgraduate studies

98

19.6

Maternal occupation

Working

494

98.8

Unemployed

6

1.2

Residency

City

433

86.6

Countryside

67

13.4

Family income (RMB)

≤5000

39

7.8

5001 ~ 10,000

79

15.8

10,001 ~ 15,000

91

18.2

15,001 ~ 20,000

89

17.8

20,001 ~ 25,000

126

25.2

25,001 ~ 30,000

36

7.2

30,001 ~ 35,000

28

5.6

≥35,001

12

2.4

Mode of delivery

Vaginal

221

44.2

Cesarean

279

55.8

Gestational week

28 ~ 32^+ 6

43

8.6

33 ~ 34^+ 6

49

9.8

35 ~ 36^+ 6

408

81.6

Labour Complication

Yes

252

50.4

No

248

49.6

Payment type of expenses

Medical insurance

393

78.6

Self-paid

92

18.4

Other

9

1.8

Unclear

6

1.2

Live with husbands during Perinatal period

Yes

487

97.4

No

13

2.6

Prenatal work

Yes

412

82.4

No

88

17.6

Length of hospital stay (hour)

36 ~ 48

26

5.2

49 ~ 72

102

20.4

73 ~ 96

98

19.6

≥97

274

54.8

Plan to work after maternity leave

Yes

411

82.2

No

89

17.8

Planned pregnancy

Prepared

328

65.6

unprepared

72

14.4

fully prepared

100

20.0

Estimated breastfeeding time (month)

<6

100

20.0

6 ~ 12

349

69.8

12 ~ 24

49

9.8

>24

2

0.4

Methods of removing breast milk during the period of mother and infant seperation

By hand

63

12.6

Breast pump

137

27.4

By hand+ Breast pump

300

60.0

Number of removing the milk by hand per day

<8

348

69.6

8 ~ 12

149

29.8

>12

3

0.6

Time of each removing the milk by hand

<30

158

31.6

30 ~ 60

300

60.0

>60

42

8.4

Visit NICU newborns

Yes

273

54.6

No

227

45.4

Deliver milk to the infants in NICU

Yes

239

47.8

No

261

52.2

Husband Age

(mean = 32.95)

18 ~ 25

15

3.0

26 ~ 30

150

30.0

31 ~ 34

195

39.0

≥35

140

28.0

Husband’s education. Level

Primary studies

13

2.6

Secondary studies

67

13.4

Undergraduate degree

279

55.8

Postgraduate studies

141

28.2

Planned pregnancy

Yes.

428

85.6

No.

72

14.4

Husband’s attitude towards breastfeeding.

5

7

1.4

6

11

2.2

7

1

0.2

8

54

10.8

9

31

6.2

10

396

79.2

Infant gender

Male

256

51.2

Female

244

48.8

Weight at birth(g)

<1500

28

5.6

1500 ~ 2000

42

8.4

2001 ~ 2500

128

25.6

2501 ~ 3000

184

36.8

≥3001

118

23.6

Apgar score

≤6

13

2.6

7 ~ 8

179

35.8

9 ~ 10

308

61.6

Type of feeding in NICU

Exclusive breastfeeding

38

7.6

Partial breastfeeding

195

39.0

Formula

267

53.4