Independent risk factors for twin pregnancy adverse fetal outcomes before 28 gestational week by first trimester ultrasound screening

Table 4 Results of bivariate logistic regression analysis suggestive of adverse pregnancy outcome

Characteristics	Odd ratios	95% confidence interval	P value
Mean PI of bilateral uterine arteries	3.524	1.015-12.236	0.047
Abnormal ultrasound findings during first trimester screening	56.146	10.086-312.547	< 0.001
Chorionicity	0.276	0.088-0.862	0.027

PI: Pulsatility index.