The Association between Intertwin Difference in First Trimester Crown-Rump Length, Nuchal Translucency, and Birth Weight Discordance in Twin Pregnancies: A Retrospective Cohort Study
Table 1
Subject characteristics in twins with a birth weight discordance < 20% vs. ≥ 20%.
Characteristics ()
Birth weight discordance < 20% ()
Birth weight discordance ≥ 20% ()
value
Maternal age, years (mean, SD)
32.7 (4.9)
33.2 (4.8)
0.3423
Maternal BMI (kg/m2) (, %)
(i) < 18.5
20 (3.01%)
3 (2.27%)
0.0818
(ii) 18.5-24.9
362 (54.44%)
74 (56.06%)
(iii) 25-29.9
171 (25.71%)
23 (17.42%)
(iv) 30+
112 (16.84)
32 (24.24%)
Parity (%)
0
423 (58.34%)
90 (62.50%)
0.4281
1
222 (30.62%)
43 (29.86%)
≥ 2
80 (11.03%)
11 (7.64%)
IVF, (%)
Yes
171 (23.68%)
30 (20.98%)
0.4841
No
551 (76.32%)
113 (79.02%)
CRL difference (mm, SD)
2.6 (2.9)
4.5 (4.4)
< 0.0001
CRL ratio (%)
0 (0)
0.1 (0.1)
< 0.0001
NT difference (mm)
0.3 (0.5)
0.4 (0.6)
0.1598
NT ratio (%)
0.1 (0.1)
0.2 (0.2)
0.0775
Average birth weight (twin 1 and 2, grams SD)
2445 (549)
2131 (638)
< .0001
Weight difference (grams, SD)
204 (155)
732 (284)
< .0001
Gestational age at delivery (weeks)
35.8 (2.6)
34.7 (3.0)
0.0002
Fetal sex
Male:Male (%)
229 (31.46%)
52 (36.88%)
0.2793
Male:Female (%)
257 (35.30%)
51 (36.17%)
Female:Female (%)
242 (33.24%)
38 (26.95%)
Chorionicity, ultrasound (, %)
DCDA
547 (76.93%)
115 (82.14%)
0.1415
MCDA
149 (20.96%)
25 (17.86%)
MCMA
15 (2.11%)
0 (0%)
Chorionicity, pathology (, %)
DCDA
461 (77.61%)
97 (80.83%)
0.2451
MCDA
120 (20.20%)
23 (19.17%)
MCMA
13 (2.19%)
0 (0%)
Legend: SD: standard deviation; BMI: body mass index; IVF: in vitro fertilization; CRL: crown rump length; NT: nuchal translucency; DCDA: dichorionic diamniotic; MCDA: monochorionic diamniotic; MCMA: monochorionic monoamniotic.
