Velamentous cord insertion in dichorionic and monochorionic twin pregnancies - Does it make a difference?

Area of Science:

• Perinatology
• Maternal-Fetal Medicine
• Obstetrics

Background:

• Velamentous cord insertion (VCI) is a placental abnormality where the umbilical cord inserts into the fetal membranes, not the placental disc.
• Twin gestations, particularly monochorionic (MC) twins, are at higher risk for various complications.
• Twin-twin transfusion syndrome (TTTS) is a serious complication unique to MC twins.

Purpose of the Study:

• To determine the prevalence of VCI in dichorionic (DC) and MC twin pregnancies, with and without TTTS.
• To investigate the association between VCI and adverse perinatal outcomes in these twin groups.

Main Methods:

• A retrospective analysis of 1498 twin placentas from two European tertiary medical centers.
• Classification of placentas into DC twins, MC twins without TTTS, and MC twins with TTTS.
• Statistical comparison of VCI prevalence and perinatal outcomes across groups.

Main Results:

• VCI prevalence was significantly higher in MC twins (34.7% without TTTS, 36.1% with TTTS) compared to DC twins (7.6%).
• In MC twins, VCI was associated with severe birth weight discordance, small for gestational age, and increased risk of intrauterine fetal demise.
• Lower gestational age at birth was observed in DC and MC twins (without TTTS) with VCI.

Conclusions:

• The prevalence of VCI is substantially higher in MC twin pregnancies than in DC twin pregnancies.
• VCI serves as a critical indicator of adverse perinatal outcomes, particularly in the context of MC twins.