 ### Description

The body weight in grams can be estimated from the gestational age assuming normal development.

Wiggelsworth

menstrual age (end of week)

mean weight in grams

8.5

1

9

2

10

4

11

7

12

14

13

23

14

43

15

70

16

100

17

140

18

190

19

240

20

300

21

360

22

430

23

501

24

600

25

700

26

800

27

900

28

1001

29

1175

30

1350

31

1501

32

1675

33

1825

34

2001

35

2160

36

2340

37

2501

38

2775

39

3001

40

3250

week gestation =

= (1.1 * (10^(-15)) * ((birthweight in grams)^5))-(9.7 * (10^(-12)) * ((birthweight in grams)^4)) + (3.3 * (10^(-8)) * ((birthweight in grams)^3)) - (0.000052 * ((birthweight in grams)^2)) + (0.0442894 * (birthweight in grams)) + 10.806891

Sung and Singer: Liveborn

gestational age (weeks)

body weight (grams), mean

body weight (grams), low

body weight (grams), high

20

381

277

485

21

426

360

492

22

473

410

536

23

524

408

640

24

584

492

676

25

655

549

761

26

739

558

920

27

836

639

1033

28

949

759

1139

29

1077

628

1526

30

1219

788

1650

31

1375

1094

1656

32

1543

1024

2062

33

1720

1140

2300

34

1905

1280

2530

35

2093

1784

2402

36

2280

1665

2895

37

2462

1641

3283

38

2634

2100

3168

39

2789

2269

3309

40

2922

2472

3372

41

3025

2425

3625

42

3091

2474

3708

week gestation with mean birthweight =

= (1.7 * (10^(-9)) * ((birthweight in grams)^3))-(0.00001 * ((birthweight in grams)^2)) + (0.0238722 * (birthweight in grams)) + 12.762229

week gestation maximum for birthweight =

= (10^(-9)) * ((birthweight in grams)^3))-(0.000007 * ((birthweight in grams)^2)) + (0.0185798 * (birthweight in grams)) + 13.553081

week gestation minimum for birthweight =

= (3.7 * (10^(-9)) * ((birthweight in grams)^3))-(0.000019 * ((birthweight in grams)^2)) + (0.0355922 * (birthweight in grams)) + 10.996627

Sung and Singer: Stillborn

gestational age (weeks)

body weight (grams), mean

body weight (grams), low

body weight (grams), high

20

313

174

452

21

353

228

478

22

398

281

515

23

450

332

568

24

510

331

689

25

581

403

759

26

663

436

890

27

758

531

985

28

864

617

1111

29

984

473

1495

30

1115

786

1444

31

1259

671

1847

32

1413

790

2036

33

1578

1324

1832

34

1750

1256

2244

35

1930

1065

2795

36

2114

1498

2730

37

2300

1653

2947

38

2485

1906

3064

39

2667

2071

3263

40

2842

2360

3324

41

3006

2245

3767

42

3156

2478

3834

week gestation with mean birthweight =

= (1.2 * (10^(-9)) * ((birthweight in grams)^3))-(0.000008 * ((birthweight in grams)^2)) + (0.0206221 * (birthweight in grams)) + 14.939943

week gestation maximum for birthweight =

= (6.2 * (10^(-10)) * ((birthweight in grams)^3))-(0.000005 * ((birthweight in grams)^2)) + (0.0155894 * (birthweight in grams)) + 14.992423

week gestation minimum for birthweight =

= (3.7 * (10^(-9)) * ((birthweight in grams)^3))-(0.000018 * ((birthweight in grams)^2)) + (0.0326279 * (birthweight in grams)) + 14.756388