Table 4

Descriptive statistics of the raw scores on triplet BW and GA, and percentage of smoking and alcohol consumption during pregnancy, as a function of zygosity

MZ

DZ

TZ


N trios

37

102

271

N boys/girls

41/70

145/161

387/426

GA mean (sd)

33.3 (2.15)

33.6 (2.89)

33.7 (2.52)

N mothers consuming alcohol

3 (8%)

19 (19%)

36 (13%)

N mothers smoking

6 (16%)

19 (19%)

49 (18%)


MZ

MZ*

DZ**

TZ


Mean BW first born (grams)

1852

1952

2017

1954

Mean BW second born (grams)

1759

1887

1941

1933

Mean BW third born (grams)

1789

1831

2107

1829

Variance triplet BW

157

230

262

215

Pair-wise covariance triplet BW

110

162

156

144

Pair-wise correlation triplet BW

0.70

0.70

0.64

0.67

SGA first born (% SE ss/US ss/US ts)

19/42/3

22/38/5

27/37/7

25/44/7

SGA sec. born (% SE ss/US ss/US ts )

41/57/14

41/24/5

14/59/13

25/41/9

SGA third born (% SE ss/US ss/US ts)

32/51/16

35/39/8

18/33/11

18/52/15


*MZ triplets from DZ trios; ** DZ triplets from DZ trios; GA = gestational age; BW = birth weight; SGA = small for gestational age; US ss = United States' singleton standard; US ts = US triplet standard; SE ss = Swedisch singleton standard; MZ = monozygotic; DZ = dizygotic; TZ = trizygotic.

Lamb et al. BMC Pediatrics 2011 11:24   doi:10.1186/1471-2431-11-24

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