Table 2

Haemodynamic variables between monochorionic twin fetuses with and without twin-twin transfusion syndrome

Variable	Twin 1 (n=87)	Twin 2 (n=89)	Recipient (n=41)	Donor (n=45)	ANOVA (p value; Bonferroni or Dunnett T3 post-hoc tests)
Values are mean (SD).
One twin 1, five recipients, and two donors were excluded because of intrauterine demise before fetal echocardiography. One twin and one recipient were excluded because of structural heart defects (pulmonary valve stenosis and pulmonary atresia intact septum respectively).
ANOVA, analysis of variance; CI, confidence interval; D, donor; R, recipient; T1, twin one (larger); T2, twin two (smaller).
Cardiothoracic ratio (%)	23.2 (3.9)	23.1 (3.4)	30.8 (9.1)	23.9 (4.9)	<0.0001
					(R–T1) 95% CI, 2.89 to 12.4; p<0.0001
					(R–T2) 95% CI, 3.02 to 12.5; p<0.0001
					(R–D) 95% CI, 1.82 to 12.08; p=0.003
					(T1–T2) 95% CI, −1.75 to 1.96; p>0.1
Aortic peak velocity (m/s)	0.60 (0.13)	0.59 (0.12)	0.73 (0.23)	0.53 (0.16)	<0.0001
					(R–T1) 95% CI, −0.002 to 0.26; p=0.05
					(R–T2) 95% CI, 0.010 to 0.27; p=0.030
					(R–D) 95% CI, 0.05 to 0.34; p=0.003
					(T1–T2) 95% CI, −0.05 to 0.07; p=0.998
Pulmonary peak velocity (m/s)	0.55 (0.13)	0.53 (0.14)	0.63 (0.14)	0.48 (0.09)	<0.0001
					(R–T1) 95% CI, 0.013 to 0.159; p=0.012
					(R–T2) 95% CI, 0.026 to 0.170; p=0.002
					(R–D) 95% CI, 0.069 to 0.237; p<0.0001
					(T1–T2) 95% CI, −0.048 to 0.071; p>0.1
Pulmonary valve diameter (cm)	0.50 (0.13)	0.48 (0.10)	0.48 (0.14)	0.42 (0.10)	0.017
					(D–T1) 95% CI, −0.15 to −0.013; p=0.011
					(D–T2) 95% CI, −0.14 to −0.0003; p=0.048
					(D–R) 95% CI, −0.15 to 0.016; p=0.202
					(T1–T2) 95% CI, −0.043 to 0.068; p>0.1
Umbilical artery pulsatility index	1.27 (0.22)	1.31 (0.31)	1.33 (0.38)	1.71 (0.46)	<0.0001
					(D–T1) 95% CI, 0.20 to 0.69; p<0.0001
					(D–T2) 95% CI, 0.14 to 0.65; p=0.001
					(D–R) 95% CI, 0.09 to 0.68; p=0.005
					(T1–T2) 95% CI, −0.18 to 0.08; p=0.876