Discrepancies in Crown-Rump Length and Abnormal Cord Insertion as Predictors of Selective Fetal Growth Restriction in Monochorionic Twin Pregnancies

This study aims to explore the significance of discrepancies in crown-rump length (CRL) and abnormal cord insertion in predicting selective fetal growth restriction (sFGR) in monochorionic (MC) twin pregnancies. Special attention was paid to determining the potential value of these factors in early pregnancy for predicting sFGR. A retrospective analysis included 131 pregnant women diagnosed with MC twin pregnancies. CRL was measured using a GE E8 color Doppler ultrasound instrument. Groups were compared based on the discrepancy in CRL (≥6 mm difference group, n = 26; <6 mm normal group, n = 105) and the presence of abnormal cord insertion (abnormal group, n = 27; normal group, n = 104). The study found no significant association between CRL discrepancy and postnatal birth-weight discordance suggestive of sFGR ( p > .05). In contrast, abnormal cord insertion was significantly associated with an increased occurrence of sFGR-related outcome ( p < .001). Specifically, sFGR-related outcome occurred in 12 of 27 cases (44.4%) in the abnormal cord insertion group, compared with 7 of 104 cases (6.7%) in the normal cord insertion group. In this retrospective MC twin cohort, abnormal cord insertion was associated with an increased risk of postnatal birth-weight discordance suggestive of sFGR, whereas CRL discrepancy showed limited discriminative ability. Because of the retrospective design, limited number of outcome events, and use of postnatal rather than standardized antenatal Doppler-based sFGR criteria, these findings should be interpreted as exploratory and require validation in larger prospective studies.