Table 1.

Comparison of baseline characteristics between growth discordant twin and normal twin

	Growth discordant group (n = 71)	Normal growth group(n = 346)	P
Maternal age ($\overline{x}\pm s$, yrs)	29.33 ± 4.72	29.42 ± 4.54	0.899
Pre-gestation BMIa ($\overline{x}\pm s$, kg/m2)	22.56 ± 3.72	22.13 ± 1.50	0.157
Pre-delivery BMI($\overline{x}\pm s$, kg/m2)	28.15 ± 2.73	28.38 ± 3.53	0.923
Gravidity [M (min-max), times]	1 (0–3)	1 (0–6)	0.071
Nulliparity(n%)	48 (67.60)	259 (74.85)	0.207
Chronic diseases(n%)	9 (12.68)	55 (15.89)	0.493
Obstetrical complications(n%)	59 (83.10)	272 (78.61)	0.395
Week for ultrasound [M (min-max), w]
First-trimester	13.00 (12.02–13.51)	13.00 (11.10–14.05)	0.221
Second-trimester	22.20 (17.02–26.03)	22.20 (21.05–27.61)	0.598
Early third-trimester	32.00 (28.03–33.00)	32.10 (28.05–34.05)	0.841
Late third-trimester	35.65 (34.01–40.30)	36.40 (34.12–40.00)	0.037
Delivery week [M (min-max), w]	36.52 (33.65–38.02)	37.10 (32.03–40.01)	0.347
Interval between delivery and the last ultrasound [M (min-max), d]	5.02 (3.15–8.12)	6.30 (4.05–8.19)	0.385

^aBMI body mass index