Head Circumference / Abdominal Circumference Ratio

                    Campbell S and Thomas A.

  Ultrasound measurement of the fetal head to abdominal

   circumference in the assessment of growth retardation

              Br J Obstet Gynaecol 1977;84:165-174

 

GA

(wks)

5th

Percentile

Mean

95th

Percentile

13-14

1.14

1.23

1.31

15-16

1.05

1.22

1.39

17-18

1.07

1.18

1.29

19-20

1.09

1.18

1.39

21-22

1.06

1.15

1.25

23-24

1.05

1.13

1.21

25-26

1.04

1.13

1.22

27-28

1.05

1.13

1.21

29-30

0.99

1.1

1.21

31-32

0.96

1.07

1.17

33-34

0.96

1.04

1.11

35-36

0.93

1.02

1.11

37-38

0.92

0.98

1.05

39-40

0.87

0.97

1.06

41-42

0.93

0.96

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