Single Fetal Demise at 10 - 14 Weeks of Monochorionic and Dichorionic Twin Pregnancy

BACKGROUND: We examined the perinatal outcomes in cases of at least one fetal demise in monochorionic and diamniotic twin pregnancies. METHODS: We reviewed the obstetric records of all Japanese twin pregnancies managed beyond 9 weeks’ gestation at Japanese Red Cross Katsushika Maternity Hospital between 2008 and 2014. RESULTS: The incidence in the monochorionic twin pregnancies was significantly higher than that in the dichorionic twin pregnancies (8.3% vs. 2.6%, odds ratio: 3.40, 95% confidence interval: 1.5 - 7.6, P < 0.01). Of these, 60.0% were diagnosed as fetal demise of both fetuses at the same time (vs. dichorionic twin pregnancy: odds ratio: 12.0, 95% confidence interval: 1.3 - 120, P = 0.04). The rate of “vanishing twin” in cases of at least one fetal demise at 10 - 14 weeks’ gestation in the monochorionic twin pregnancies was significantly lower than that in the diamniotic twin pregnancies (30.0% vs. 88.9%, odds ratio: 0.05, 95% confidence interval: 0.01 - 0.53, P = 0.01). CONCLUSION: The incidence of fetal demise and the influence on the co-twin in monochorionic twin pregnancy is greater than those in dichorionic twin pregnancy.