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

Figure 1 Twin pregnancy ultrasound scan at the 13 + 2 gestational week. A: A dichorionic diamniotic twin pregnancy with two placentas and two distinct amniotic cavities; B: Fetus A with normal ultrasound findings; C: Fetus B with omphalocele shown on crown-rump length section as a mass protrusion of the intestine and liver through a navel hernia in the abdominal wall; D: Color Doppler showed that the blood supply of the mass was from Fetus B. CRL: Crown-rump length; NT: Nuchal translucency.

Figure 2 Receiver operating characteristic curve for mean pulsatility index of bilateral uterine arteries and mean resistance index of bilateral uterine arteries. The area under the receiver operating characteristic (ROC) curve of mean pulsatility index (PI) of bilateral uterine arteries (UtAs; blue line) was 0.650 with a Youden index of 0.309 and the cutoff value as 1.393. The area under the ROC curve of mean resistance index (RI) of bilateral UtAs (pink line) was 0.661 with a Youden index of 0.319 and the cutoff value as 0.683. Mean PI of bilateral UtAs larger than 0.650, or mean RI larger than 1.393 suggested a higher risk of adverse fetal outcomes. ROC: Receiver operating characteristic; PI: Pulsatility index; RI: Resistance index.