Hamilton describes a case of twins in which one fetus died from the effects of an injury between the fourth and fifth months and the second arrived at full period.

Moore cites an instance in which one of the fetuses perished about the third month, but was not expelled until the seventh, and the other was carried to full term.

Wilson speaks of a secondary or blighted fetus of the third month with fatty degeneration of the membranes retained and expelled with its living twin at the eighth month of uterogestation.
There was a case at Riga in 1839 of a robust girl who conceived in February, and in consequence her menses ceased.

In June she aborted, but, to her dismay, soon afterward the symptoms of advanced pregnancy appeared, and in November a full-grown child, doubtless the result of the same impregnation as the fetus, was expelled at the fourth month.
In 1860 Schuh reported an instance before the Vienna Faculty of Medicine in which a fetus was discharged at the third month of pregnancy and the other twin retained until full term.

The abortion was attended with much metrorrhagia, and ten weeks afterward the movements of the other child could be plainly felt and pregnancy continued its course uninterrupted.