# Table 2

Weekly values for P, PQ and PR Estimated value for the P wave, PQ interval and PR interval and their respective 90% prediction interval (PI) based on each interval's best fitting regression model. Values from the 17th to the 42nd week are given. N is the number of case avaliable for the model in any respective week.

Gestational age week

N

P wave (ms) estimated value (90% PI)

PQ interval (ms) estimated value (90% PI)

PR interval (ms) estimated value (90% PI)

17

1

37 (27 – 48)

52 (34 – 71)

89 (67 – 110)

18

5

39 (28 – 49)

54 (35 – 72)

91 (70 – 113)

19

8

40 (30 – 50)

54 (36 – 73)

94 (73 – 115)

20

9

41 (31 – 52)

55 (37 – 74)

96 (75 – 117)

21

8

43 (32 – 53)

56 (38 – 74)

98 (77 – 119)

22

9

44 (34 – 55)

56 (38 – 75)

100 (80 – 121)

23

12

45 (35 – 56)

57 (39 – 75)

102 (81 – 123)

24

10

47 (36 – 57)

57 (39 – 75)

104 (83 – 125)

25

9

48 (38 – 59)

57 (39 – 75)

106 (85 – 127)

26

8

50 (39 – 60)

57 (39 – 75)

107 (86 – 128)

27

11

51 (41 – 61)

57 (39 – 75)

108 (88 – 129)

28

16

52 (42 – 63)

57 (38 – 75)

110 (89 – 130)

29

11

54 (43 – 64)

56 (38 – 75)

111 (90 – 131)

30

12

55 (45 – 65)

56 (38 – 74)

111 (90 – 132)

31

7

56 (46 – 67)

55 (37 – 73)

112 (91 – 133)

32

10

58 (47 – 68)

54 (36 – 73)

112 (92 – 133)

33

11

59 (49 – 70)

53 (35 – 72)

113 (92 – 134)

34

9

61 (50 – 71)

52 (34 – 71)

113 (92 – 134)

35

12

62 (52 – 72)

51 (33 – 69)

113 (92 – 134)

36

10

63 (53 – 74)

50 (31 – 68)

113 (92 – 134)

37

6

65 (54 – 75)

48 (30 – 67)

113 (92 – 134)

38

14

66 (56 – 76)

47 (28 – 65)

112 (91 – 133)

39

9

67 (57 – 78)

45 (26 – 63)

112 (91 – 133)

40

6

69 (58 – 79)

43 (25 – 62)

111 (90 – 132)

41

2

70 (60 – 81)

41 (22 – 60)

110 (89 – 131)

42

1

72 (61 – 82)

39 (20 – 58)

109 (88 – 131)

van Leeuwen et al. BMC Pregnancy and Childbirth 2004 4:6   doi:10.1186/1471-2393-4-6