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Table 3 Percentiles for twin fetal sonography measurements by gestational age

From: Fetal growth standards for Chinese twin pregnancies

Gestational age, wks

Percentiles

3rd

5th

10th

25th

50th

75th

90th

95th

97th

Biparietal diameter, mm (MC & DC twins)

 14

25.9

26.2

26.7

27.4

28.3

29.1

30.0

30.5

30.8

 15

28.7

29.0

29.5

30.3

31.3

32.2

33.1

33.7

34.0

 16

31.5

31.9

32.4

33.3

34.3

35.4

36.4

37.0

37.4

 17

34.5

34.8

35.4

36.4

37.5

38.7

39.8

40.4

40.8

 18

37.5

37.9

38.5

39.6

40.8

42.0

43.2

43.9

44.4

 19

40.5

40.9

41.6

42.7

44.1

45.4

46.7

47.4

47.9

 20

43.5

44.0

44.7

46.0

47.4

48.8

50.1

51.0

51.5

 21

46.6

47.1

47.8

49.2

50.6

52.2

53.6

54.5

55.1

 22

49.6

50.1

50.9

52.3

53.9

55.5

57.1

58.0

58.6

 23

52.6

53.1

54.0

55.5

57.1

58.9

60.5

61.4

62.1

 24

55.5

56.1

57.0

58.5

60.3

62.1

63.8

64.8

65.5

 25

58.3

58.9

59.9

61.5

63.3

65.2

67.0

68.1

68.8

 26

61.1

61.7

62.7

64.4

66.3

68.3

70.1

71.2

72.0

 27

63.7

64.3

65.4

67.1

69.1

71.2

73.1

74.3

75.0

 28

66.2

66.9

68.0

69.8

71.8

74.0

76.0

77.2

78.0

 29

68.6

69.3

70.4

72.3

74.4

76.6

78.7

79.9

80.7

 30

70.9

71.6

72.7

74.7

76.9

79.1

81.2

82.5

83.4

 31

73.0

73.8

74.9

76.9

79.2

81.5

83.7

85.0

85.8

 32

75.0

75.8

77.0

79.0

81.3

83.7

85.9

87.3

88.2

 33

76.9

77.7

78.9

81.0

83.4

85.8

88.1

89.4

90.3

 34

78.7

79.5

80.7

82.9

85.3

87.7

90.0

91.4

92.4

 35

80.4

81.2

82.4

84.6

87.0

89.6

91.9

93.3

94.3

 36

81.9

82.7

84.0

86.2

88.7

91.3

93.6

95.1

96.1

 37

83.4

84.2

85.5

87.7

90.3

92.9

95.3

96.8

97.7

 38

84.8

85.6

87.0

89.2

91.8

94.4

96.8

98.3

99.3

Head circumference, mm (MC & DC twins)

 14

92.4

93.2

94.6

96.8

99.4

102.1

104.6

106.1

107.1

 15

102.6

103.5

105.0

107.5

110.4

113.4

116.1

117.7

118.8

 16

113.2

114.2

115.8

118.6

121.8

125.0

128.0

129.8

131.0

 17

124.1

125.2

127.0

130.0

133.4

137.0

140.2

142.2

143.5

 18

135.2

136.4

138.3

141.6

145.3

149.2

152.7

154.8

156.3

 19

146.4

147.7

149.8

153.3

157.3

161.5

165.3

167.6

169.1

 20

157.7

159.1

161.3

165.1

169.4

173.8

177.9

180.4

182.0

 21

168.9

170.4

172.8

176.8

181.4

186.1

190.5

193.1

194.8

 22

180.0

181.6

184.1

188.4

193.3

198.2

202.9

205.7

207.5

 23

190.9

192.6

195.2

199.8

204.9

210.1

215.0

218.0

219.9

 24

201.5

203.3

206.1

210.8

216.2

221.7

226.8

230.0

232.0

 25

211.8

213.7

216.6

221.6

227.2

233.0

238.3

241.5

243.7

 26

221.7

223.7

226.7

231.9

237.7

243.8

249.3

252.7

254.9

 27

231.2

233.3

236.4

241.8

247.8

254.1

259.8

263.3

265.6

 28

240.3

242.4

245.6

251.2

257.4

263.9

269.8

273.5

275.8

 29

248.8

251.0

254.3

260.1

266.5

273.2

279.3

283.0

285.5

 30

256.9

259.1

262.6

268.4

275.1

281.9

288.2

292.0

294.5

 31

264.6

266.8

270.3

276.3

283.2

290.1

296.6

300.5

303.1

 32

271.7

274.0

277.6

283.7

290.7

297.8

304.4

308.4

311.0

 33

278.4

280.8

284.4

290.7

297.8

305.0

311.7

315.8

318.5

 34

284.7

287.1

290.8

297.2

304.4

311.8

318.6

322.8

325.5

 35

290.7

293.1

296.9

303.3

310.7

318.1

325.1

329.3

332.0

 36

296.3

298.7

302.6

309.1

316.5

324.1

331.1

335.4

338.2

 37

301.6

304.1

308.0

314.6

322.1

329.8

336.9

341.2

344.1

 38

306.8

309.3

313.2

319.9

327.5

335.3

342.5

346.8

349.7

Abdominal circumference, mm (MC & DC twins)

 14

77.8

78.7

80.1

82.5

85.3

88.2

90.9

92.5

93.6

 15

86.8

87.8

89.4

92.1

95.2

98.4

101.4

103.2

104.4

 16

96.3

97.4

99.1

102.1

105.5

109.1

112.4

114.4

115.7

 17

106.0

107.2

109.1

112.4

116.2

120.0

123.6

125.9

127.3

 18

116.0

117.3

119.4

123.0

127.1

131.3

135.2

137.6

139.2

 19

126.1

127.6

129.8

133.7

138.1

142.7

146.9

149.5

151.2

 20

136.4

138.0

140.4

144.5

149.3

154.2

158.8

161.6

163.4

 21

146.7

148.4

151.0

155.4

160.5

165.7

170.6

173.6

175.6

 22

157.0

158.7

161.5

166.2

171.7

177.2

182.4

185.6

187.7

 23

167.1

169.0

172.0

177.0

182.7

188.6

194.1

197.5

199.7

 24

177.2

179.2

182.3

187.6

193.6

199.9

205.7

209.2

211.6

 25

187.1

189.1

192.4

198.0

204.3

210.9

217.0

220.7

223.2

 26

196.7

198.9

202.3

208.1

214.8

221.7

228.0

231.9

234.5

 27

206.2

208.5

212.0

218.1

225.0

232.2

238.8

242.9

245.5

 28

215.4

217.8

221.4

227.8

235.0

242.4

249.3

253.5

256.3

 29

224.4

226.8

230.7

237.2

244.7

252.4

259.5

263.9

266.8

 30

233.2

235.7

239.6

246.4

254.1

262.1

269.5

274.0

277.0

 31

241.7

244.3

248.4

255.4

263.4

271.6

279.2

283.8

286.9

 32

250.1

252.8

257.0

264.2

272.4

280.9

288.7

293.5

296.7

 33

258.5

261.2

265.5

272.9

281.3

290.0

298.1

303.0

306.3

 34

266.7

269.5

274.0

281.6

290.2

299.1

307.4

312.4

315.8

 35

275.0

277.9

282.4

290.2

299.1

308.2

316.7

321.9

325.3

 36

283.3

286.3

291.0

298.9

308.0

317.4

326.1

331.4

334.9

 37

291.8

294.9

299.7

307.8

317.1

326.7

335.6

341.1

344.7

 38

300.6

303.8

308.7

317.0

326.6

336.4

345.5

351.1

354.7

Femur length, mm (MC & DC twins)

 14

13.1

13.3

13.6

14.1

14.7

15.3

15.9

16.3

16.5

 15

15.4

15.6

15.9

16.5

17.2

17.9

18.6

19.0

19.2

 16

17.8

18.0

18.4

19.1

19.8

20.6

21.4

21.8

22.1

 17

20.3

20.5

21.0

21.7

22.6

23.5

24.3

24.8

25.2

 18

22.9

23.2

23.6

24.5

25.4

26.4

27.4

27.9

28.3

 19

25.5

25.9

26.4

27.3

28.3

29.4

30.5

31.1

31.5

 20

28.2

28.6

29.1

30.1

31.3

32.5

33.6

34.2

34.7

 21

30.9

31.3

31.9

32.9

34.2

35.4

36.6

37.4

37.8

 22

33.5

33.9

34.6

35.7

37.0

38.4

39.7

40.4

40.9

 23

36.1

36.5

37.2

38.4

39.8

41.2

42.6

43.4

43.9

 24

38.5

39.0

39.7

41.0

42.5

44.0

45.4

46.2

46.8

 25

40.9

41.4

42.2

43.5

45.0

46.6

48.0

48.9

49.5

 26

43.2

43.7

44.5

45.8

47.4

49.0

50.5

51.5

52.1

 27

45.3

45.8

46.6

48.1

49.7

51.4

52.9

53.9

54.5

 28

47.3

47.9

48.7

50.2

51.8

53.5

55.1

56.1

56.7

 29

49.2

49.8

50.7

52.1

53.8

55.6

57.2

58.2

58.8

 30

51.1

51.6

52.5

54.0

55.7

57.5

59.2

60.2

60.8

 31

52.8

53.4

54.3

55.8

57.5

59.3

61.0

62.0

62.7

 32

54.5

55.1

56.0

57.5

59.3

61.1

62.8

63.8

64.5

 33

56.2

56.8

57.7

59.3

61.0

62.9

64.6

65.6

66.3

 34

57.9

58.5

59.4

61.0

62.8

64.6

66.3

67.4

68.1

 35

59.6

60.2

61.2

62.8

64.6

66.4

68.2

69.2

69.9

 36

61.5

62.1

63.0

64.6

66.5

68.3

70.1

71.1

71.8

 37

63.5

64.1

65.0

66.6

68.5

70.4

72.1

73.2

73.9

 38

65.6

66.3

67.2

68.9

70.7

72.7

74.4

75.5

76.2

  1. Note: MC monochorionic, DC dichorionic