3.1 | Population characteristics
Demographic details of the study population are described inTable 1 . Overall, there were no significant differences between these two groups in maternal age, pre-gestational maternal body mass index, weight gain during pregnancy, primigravida, and the method of conception. The gestational age at delivery of DCDA-D pregnancies was significantly earlier (1 week) than DCDA-C pregnancies. The postnatal outcomes of DCDA-C and DCDA-D twins are summarized in Table 2 . No discrepancies were observed within DCDA-D co-twin pairs (comparison 3) regarding fetal abdominal circumference (AC), fetal head circumference (HC), height, pH in cord blood, and Apgar score at 5 min, whilst significant disparities within co-twins were observed for BW and Apgar scores at 1 min. In addition, the Apgar score at 1 and 5 min, pH in cord blood, and the indicators of fetal development, including AC, HC, height, and birthweight, were profoundly discordant for comparisons 1 and 2.