Single fetal death occurs in 0.5–6.8% of twin pregnancies. The earlier twins are diagnosed, the more likely one twin is to demise. The three major factors affecting outcome are the gestational age at death, the cause of death and the chorionicity of the twins. With dichorionic twins, provided the cause of death is intrinsic to the dead twin, complications are unusual. However, the death of a monochorionic twin may be followed by cerebral infarction in the surviving co-twin, as well as renal, hepatic and cutaneous damage. In 13 studies, single fetal death was associated with serious morbidity in 24% of 119 surviving monochorionic children. It is likely that the cause of the neurological damage is acute exsanguination of the surviving twin into the circulation of the dead twin through placental vascular anastomoses.
The optimal management of single fetal death ≥ 36 weeks’ gestation is elective delivery. For dichorionic twins remote from term, an expectant approach leads to enhanced maturity and an increased chance of survival. For the survivors of monochorionic single fetal deaths, there is
debate as to whether the optimal management is delivery or expectant.
However, delivery is unlikely to improve outcome if the reason for neurological injury is acute hypoperfusion immediately after the demise of the sibling. Thus a conservative approach is usually adopted with serial ultrasound follow-up (and/or MRI) to look for ventriculomegaly,
porencephaly, and microcephaly.
Source: Forfar and Arneil’s Textbook of Pediatrics, 7E