5 - 6 days after child birth

1 month after childbirth

12 months after childbirth

Quit smokers

Resumed smokers

Quit smokers

Resumed smokers

n = 241

n = 201

n = 9

p value

n = 106

n = 40

p value

Age

>10

29 - 20

45 - 30

5

140

96

2

121

78

0

7

2

-

1

46

59

0

24

16

-

Education

High school

University

140

101

111

90

6

3

NS

46

56

18

18

NS

Annual income

(million yen)

<300

301-

500-

85

110

46

73

88

40

2

3

4

NS

32

47

24

13

18

8

NS

Frequency of delivery

Primiparas

Multiparas

135

106

110

91

6

3

NS

65

41

17

33

^***

Experience of abortion

Yes

No

99

142

86

115

2

7

NS

42

64

25

15

^*

Birth weight

<2500

≥2500

22

219

19

182

1

8

NS

11

95

4

36

NS

Spousal smoking

Yes

No

196

45

157

43

8

1

NS

71

35

37

3

^***

Alcohol consumption by women

Yes

No

0

241

15

178

3

6

^*

43

63

26

14

^***

Feeding

Breast feeding

Bottle feeding

234

7

131

63

2

7

^**

82

21

17

23

^***

Worries about baby care

Yes

No

53

188

33

164

3

6

NS

10

95

7

33

NS