Perinatal outcome and neurological follow up of the cotwins in twin pregnancies complicated by single intrauterine death.

OBJECTIVE: To review the outcome of twin pregnancies complicated by single fetal intrauterine death (IUD) managed at our Centre and to evaluate the neurological follow up of the surviving cotwins. STUDY DESIGN: Twenty-three twin pregnancies (10 dichorionic and 13 monochorionic diamniotic) complicated by IUD in the II or III trimester were seen at our Centre during the study period (2001-2006). All patients were managed conservatively unless non-reassuring signs of fetal well-being were present at ultrasound examination or CTG after 28 weeks, suggesting immediate delivery. Serial scans after the diagnosis of single death were performed and, in addition, eight monochorionic twin pregnancies underwent prenatal MRI in order to identify the presence of cerebral lesions in the survivors. Live born surviving cotwins underwent neurological follow up. RESULTS: In the monochorionic group one cotwin died in utero and one in the neonatal period with a perinatal survival rate of 83.4% (10/12) (excluding one case who opted for termination of pregnancy); in the dichorionic group perinatal survival rate was 100%. In all monochorionic cases there were no signs of ischemic brain lesions in the surviving cotwins at the diagnosis of single death and during ultrasonographic follow up. In monochorionic pregnancies prenatal MRI, when performed, was negative for signs of brain damage in the surviving cotwins. Gestational age at delivery was not statistically different between monochorionic and dichorionic pregnancies (36 (range, 28.4-40.2) vs. 34.6 (range, 28.2-41.3) weeks) (p=0.6) and the rate of early preterm delivery before 32 weeks was 23.8% (5/21) and independent from chorionicity (18.2% vs. 30%, p=0.5). Neurodevelopmental follow up was available for 18/20 live born survivors (85%) and was normal in all but one twin; this case was born from a dichorionic pregnancy with a suspicion of congenital infection. CONCLUSIONS: Our data confirmed a trend to a higher risk of perinatal mortality of cotwins in monochorionic twin pregnancies compared to dichorionic ones. In our experience prenatal ultrasound and MRI were useful to exclude cerebral lesions in utero and subsequent neurological sequelae in surviving monochorionic cotwins, even if definitive conclusions, especially on MRI, are limited by the small number of cases in our study.