TABLE C-5 Mean Weights and Percentiles for Placentas (singletons, twins, and triplets)

Gestational age (weeks)

90th Percentile

Mean Placental Weight

10th Percentile

Cases (n)

Singletons

Twins

Triplets

Singletons

Twins

Triplets

Singletons

Twins

Triplets

Singletons

Twins

Triplets

19

263

212

161

2

20

270

285

218

253

166

226

3

3

21

172

286

320

143

231

284

114

176

257

3

2

2

22

191

310

345

157

251

319

122

191

289

6

5

2

23

211

343

400

172

276

361

133

210

331

7

2

3

24

233

382

445

189

307

406

145

232

371

9

3

5

25

256

426

498

208

341

456

159

257

408

19

5

6

26

280

475

558

227

380

509

175

284

444

14

4

6

27

305

528

630

248

421

564

192

314

480

9

8

4

28

331

584

697

270

464

621

210

345

516

16

7

5

29

357

641

772

293

509

679

229

377

553

11

12

6

30

384

700

849

316

554

738

249

409

591

12

17

10

31

411

758

925

340

600

797

269

441

631

14

13

15

32

438

815

1,000

364

644

855

290

472

674

24

29

7

33

464

870

1,072

387

687

911

311

503

719

30

27

14

34

491

923

1,139

411

727

965

331

531

768

32

53

43

35

516

971

1,200

434

764

1,017

352

558

821

44

52

33

36

542

1,014

1,253

457

798

1,065

372

582

878

36

66

19

37

566

1,051

1,297

478

827

1,108

391

602

940

32

58

8

38

589

1,082

1,330

499

850

1,147

409

619

1,007

62

54

5

39

611

1,105

519

868

426

631

103

38

40

632

1,118

537

879

442

639

193

47

41

651

1,123

553

882

456

642

8 7

1 2

SOURCES: Pediatric Pathology & Laboratory Medicine by Pinar H., C. J. Sung, C. E. Oyer and D. B. Singer. Copyright 1996 by Informa Clinical Medicine—Journals. Reproduced with permission of Informa Clinical Medicine—Journals via Copyright Clearance Center; Reprinted from Pinar H., M. Stephens, D. B. Singer, T. K. Boyd, S. M. Pflueger, D. L. Gang, D. J. Roberts and C. J. Sung. 2002. Triplet placentas: reference values for weights. Pediatric and Developmental Pathology 5(5): 495-498 with kind permission from Springer Science and Business Media.



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