Table 2 Sleep characteristics of included participants at the three time points, week 32 of pregnancy, and week 8 and year 2 postpartum

Sleep duration variables

Time in bed, hh:mm

8:42

(1:16)

8:51

(1:22)

7:44

(0:51)

.010

0.11

<.001

0.98

<.001

0.90

Sleep duration, hh:mm

7:16

(1:23)

6:31

(1:16)

6:52

(0:58)

<.001

0.57

<.001

0.31

<.001

0.34

<7 h, % (n)

27.4 %

(742)

49.8 %

(958)

35.2 %

(680)

-

-

-

7-8 h, % (n)

31.4 %

(852)

29.8 %

(573)

45.1 %

(871)

-

-

-

≥8 h, % (n)

41.2 %

(1117)

20.4 %

(393)

19.7 %

(381)

-

-

-

SOL/WASO, hh:mm

1:28

(1:18)

2:21

(1:21)

0:52

(0:53)

<.001

0.67

<.001

1.30

<.001

0.54

Sleep efficiency, %

83.6 %

(13.3)

74.2 %

(13.2)

89.0 %

(10.5)

<.001

0.71

<.001

1.24

<.001

0.45

Insomnia variables

DSM-IV Insomnia, % (n)

60.8 %

(1778)

59.6 %

(1305)

40.8 %

(835)

1.00

-

<.001

-

<.001

-

Difficulties initiating sleep, days/week

2.69

(2.38)

1.45

(2.00)

1.61

(1.97)

<.001

0.56

0.42

0.08

<.001

0.49

Difficulties maintaining sleep, days/week

2.93

(2.36)

4.24

(2.76)

1.66

(2.12)

<.001

0.51

<.001

1.05

<.001

0.57

Early morning awakenings, days/week

2.27

(2.27)

1.25

(2.06)

1.16

(1.81)

<.001

0.47

0.62

0.05

<.001

0.54

Non-restorative sleep, days/week

3.56

(2.16)

3.70

(2.31)

3.55

(2.30)

0.17

0.06

0.16

0.07

1.00

0.00

Daytime impairment, days/week

2.28

(2.20)

1.76

(2.00)

1.83

(2.00)

<.001

0.25

0.66

0.03

<.001

0.21

Sleep dissatisfaction, days/week

3.50

(2.30)

2.98

(2.35)

2.91

(2.32)

<.001

0.22

1.00

0.03

<.001

0.26