Placental recruitment after spontaneous single fetal demise in monochorionic diamniotic twin pregnancies

The incidence of single fetal demise in monochorionic diamniotic twin pregnancies is approximately 7.5%. In single fetal demise cases, the placental region of the demised fetus is almost infarcted or necrotic at the time of delivery. Further, it has been reported that in some cases, a surviving fetus uses all regions of the placenta after a single fetal demise. Thus, in the present study, we investigated the incidence and natural prognosis of placental recruitment in spontaneous single fetal demise cases over a period of 11 years.

All 306 monochorionic diamniotic twin pregnancies that were delivered between 2011 and 2021 in our institution were included in this retrospective cohort study. The placenta and umbilical cord were investigated, and the type of anastomosis was identified by color injection. Furthermore, the number and direction of arteriovenous anastomoses were recorded.

There were eight single fetal demise cases, excluding cases of twin-reversed arterial perfusion sequence and after fetoscopic laser photocoagulation. The placental region of six demised fetuses had an infarction or necrotic region. In two cases, an infarction or necrosis was not observed, and the surviving fetus used all regions of the placenta.

The surviving fetus in monochorionic diamniotic twin pregnancies with superficial anastomoses can use all regions of the placenta, even after a spontaneous single fetal demise. Further studies are needed to determine the difference between such cases and in those in which only the localized regions of the placenta can be used.