Table 3 Weekly values for QRS. Estimated value for the QRS complex (all, female and male data) and their respective 90% prediction interval (PI) based on the best fitting regression model. Values from the 17^th to the 42^nd week are given. N is the number of cases available for the model in any respective week. p values comparing the female and male QRS durations are given showing the transition to statistically distinguishable values at the 31^st week (p values < .05 in bold type).

17

1

33 (28 – 40)

30 (24 – 37)

1

34 (29 – 41)

18

5

35 (29 – 41)

4

32 (26 – 39)

1

35 (30 – 42)

19

8

36 (30 – 42)

5

34 (28 – 41)

3

37 (31 – 44)

20

9

37 (31 – 44)

5

36 (30 – 42)

4

38 (32 – 45)

21

8

38 (32 – 45)

3

38 (32 – 44)

5

39 (33 – 46)

22

9

39 (33 – 46)

5

39 (33 – 45)

4

40 (34 – 48)

23

13

40 (34 – 47)

7

40 (34 – 46)

6

41 (34 – 49)

24

11

41 (35 – 49)

8

41 (35 – 48)

3

42 (35 – 50)

25

9

42 (36 – 50)

4

43 (36 – 49)

5

43 (36 – 51)

0.576

26

8

43 (37 – 51)

6

44 (37 – 50)

2

44 (37 – 53)

0.537

27

11

44 (37 – 52)

5

44 (38 – 51)

6

45 (38 – 54)

0.467

28

16

45 (38 – 53)

8

45 (39 – 51)

8

46 (39 – 55)

0.335

29

11

46 (39 – 54)

9

46 (40 – 52)

2

47 (40 – 56)

0.211

30

12

47 (40 – 55)

4

47 (41 – 53)

8

48 (40 – 57)

0.100

31

7

48 (41 – 57)

1

48 (41 – 54)

6

49 (41 – 58)

0.034

32

10

49 (41 – 58)

5

48 (42 – 54)

5

50 (42 – 59)

0.009

33

11

50 (42 – 59)

8

49 (43 – 55)

3

51 (43 – 61)

0.001

34

9

51 (43 – 60)

3

49 (43 – 55)

6

52 (43 – 62)

<0.001

35

12

52 (44 – 61)

3

50 (44 – 56)

9

53 (44 – 63)

<0.001

36

10

52 (44 – 62)

3

50 (44 – 57)

7

54 (45 – 64)

<0.001

37

6

53 (45 – 63)

4

51 (45 – 57)

2

54 (46 – 65)

<0.001

38

14

54 (46 – 64)

6

51 (45 – 57)

8

55 (46 – 66)

<0.001

39

9

55 (47 – 65)

5

52 (46 – 58)

4

56 (47 – 67)

<0.001

40

6

56 (47 – 66)

1

52 (46 – 58)

5

57 (48 – 68)

41

2

57 (48 – 67)

1

53 (46 – 59)

1

58 (48 – 69)

42

1

58 (49 – 68)

53 (47 – 59)

1

59 (49 – 70)