Description

The crown rump length can be estimated from the gestational age if there is normal development.

Wiggelsworth

menstrual age (end of week)

crown rump mm

8.5

27

9

31

10

40

11

50

12

61

13

74

14

87

15

101

16

116

17

130

18

142

19

153

20

164

21

175

22

186

23

197

24

208

25

218

26

228

27

238

28

247

29

258

30

265

31

274

32

283

33

293

34

302

35

311

36

321

37

331

38

341

39

352

40

362

week gestation =

= (-7.4 * (10^(-14)) * (((crown rump length in cm) * 10)^6)) + (9.5 * (10^(-11)) * (((crown rump length in cm) * 10)^5)) + (-5.1 * (10^(-8)) * (((crown rump length in cm) * 10)^4)) + (1.44 * (10^(-5)) * (((crown rump length in cm) * 10)^3)) + (-0.002046 * (((crown rump length in cm) * 10)^2)) + (0.2124544 * ((crown rump length in cm) * 10)) + 3.9969113

Sung and Singer: Liveborn

gestational age (weeks)

crown rump (cm), mean

crown rump (cm), low

crown rump (cm), high

20

18.3

16.1

20.5

21

19.1

17.9

20.3

22

20

18.7

21.3

23

20.8

18.9

22.7

24

21.6

20.2

23

25

22.5

20.9

24.1

26

23.3

21.4

25.2

27

24.2

21.7

26.7

28

25

23.3

26.7

29

25.9

23.1

28.7

30

26.7

23.4

30

31

27.6

23.8

31.4

32

28.4

18.9

37.9

33

29.3

26

32.6

34

30.1

25.8

34.4

35

30.9

28.9

32.9

36

31.8

27.9

35.7

37

32.6

27.6

37.6

38

33.5

30.3

36.7

39

34.3

32.4

36.2

40

35.2

32.4

38

41

36

32.9

39.1

42

36.9

34.5

39.3

week gestation with mean crown rump length =

= (1.1830405 * (crown rump length in cm))-1.610768

week gestation maximum for crown rump length =

= (1.0020557 * (crown rump length in cm)) + 0.4590862

week gestation minimum for crown rump length =

= (1.1996472 * (crown rump length in cm)) + 1.4260879

Sung and Singer: Stillborn

gestational age (weeks)

crown rump (cm), mean

crown rump (cm), low

crown rump (cm), high

20

18

16

20

21

18.9

14.1

23.7

22

19.8

10.2

29.4

23

20.6

18.3

22.9

24

21.5

18.4

24.6

25

22.3

18.3

26.3

26

23.2

19.1

27.3

27

24.1

21.2

27

28

24.9

22.7

27.1

29

25.8

21.7

29.9

30

26.6

24.2

29

31

27.5

24.5

30.5

32

28.4

25.6

31.2

33

29.2

25.7

32.7

34

30.1

26.6

33.6

35

30.9

27

34.8

36

31.8

27.8

35.8

37

32.7

27.6

37.8

38

33.5

30.9

36.1

39

34.4

30.7

38.1

40

35.2

28.8

41.6

41

36.1

32.4

39.8

42

36.9

34.9

38.9

week gestation with mean crown rump length =

= (1.1635879 * (crown rump length in cm)) - 0.993608

week gestation maximum for crown rump length =

= (1.095292 * (crown rump length in cm)) - 3.196922

week gestation minimum for crown rump length =

= (1.0575944 * (crown rump length in cm)) + 5.8614413

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