Velamentous cord insertion in monochorionic twins with or without twin-twin transfusion syndrome: Does it matter?

Objective: To study the association between velamentous cord insertion (VCI) and different outcomes in monochorionic twins with and without twin twin transfusion syndrome (TTTS). Methods: We recorded the cord insertion type in all consecutive monochorionic placentas examined in two tertiary medical centers. The association between VU and several outcomes was estimated. Results: A total of 630 monochorionic placentas with TTTS (n = 304) and without TTTS (n = 326) were studied. The incidence of VU in the TITS and non-TTTS group was 36.8% and 35.9%, respectively (P = 0.886). The presence of VCI in one twin was significantly associated with small for gestational age (SGA) status (odds ratio [OR] 1.45, 95% CI 1.13, 1.87) and severe birth weight discordance (OR 3.09, 95% CI 1.93, 4.96). Our results also showed significant interaction between TITS and VCI when we considered intrauterine fetal demise (IUFD) and gestational age (GA) at birth. The prevalence of IUFD in monochorionic pregnancies without TTTS increased from 4.6% to 14.1% in the presence of VCI (P = 0.027). In the TITS group, the prevalence of IUFD was comparable in the absence or presence of VCI. Similarly, GA at birth was significantly lower in the presence of VCI only in the non-TTTS group. Conclusion: Our findings suggest that VCI is not associated with the development of TTTS but increases the risk of adverse outcomes. Both VCI and TITS independently increase the prevalence of IUFD and lower GA at birth in a similar way, showing that VCI is an important indicator of adverse perinatal outcome in monochorionic twins. (C) 2013 Elsevier Ltd. All rights reserved.