RESUMEN
PROBLEM: In twin pregnancies, factors that influence total umbilical cord IgG concentration and IgG transfer ratio are not well known. METHOD: Blood samples were prospectively collected from 57 twin pregnancies. Stepwise multivariate regression analysis was used to evaluate the association between total IgG levels in the umbilical cord blood and IgG transfer ratio according to serum IgG concentration, pregnancy chorionicity, the presence of abnormal umbilical artery pulsatility index, intrauterine growth restriction, gestational age at delivery (GAD), birthweight, and placental weight. RESULTS: Umbilical cord IgG concentration showed a positive correlation with serum IgG concentration and GAD; levels were significantly lower in monochorionic compared with dichorionic pregnancies. IgG transfer ratio also increased with GAD but was inversely correlated with serum IgG concentration levels. CONCLUSION: In twin pregnancies, besides serum IgG concentration and GAD, chorionicity also influences umbilical cord IgG concentration. Monochorionic twins have lower IgG cord concentration than dichorionic twins.