Uterine Artery Pulsatility Index (PI)

                                    Rizzo G, Arduini D, Romanini C

               Uterine artery doppler velocity waveforms in twin pregnancies.

                                  Obstet Gynecol 1993;82(6):978-983

 

GA

(wks)

50th

 PERCENTILE

5th

 PERCENTILE

95th

PERCENTILE

20

1.54

1.04

2.03

21

1.47

0.98

1.96

22

1.41

0.92

1.9

23

1.35

0.86

1.85

24

1.3

0.81

1.79

25

1.25

0.76

1.74

26

1.2

0.71

1.69

27

1.16

0.67

1.65

28

1.12

0.63

1.61

29

1.08

0.59

1.57

30

1.05

0.56

1.54

31

1.02

0.53

1.51

32

0.99

0.5

1.48

33

0.97

0.48

1.46

34

0.95

0.46

1.44

35

0.94

0.44

1.43

36

0.92

0.43

1.42

37

0.92

0.42

1.41

38

0.91

0.42

1.4

39

0.91

0.42

1.4

40

0.91

0.42

1.4

41

0.92

0.42

1.41

42

0.93

0.43

1.42