ABSTRACT
It is now accepted that the risk of loss of one or more embryos/fetuses in a multiple gestation is higher than the risk of loss of a singleton pregnancy. Most losses occur very early in gestation, and are only detected because an initial ultrasound examination shows one or more gestational sacs that subsequently ‘vanish’. The subject of the vanishing fetus is addressed in detail in Chapter 17 of this book. In a similar fashion, fetuses in multiple gestations have a higher likelihood of perinatal loss, also addressed elsewhere in this volume (see Chapter 1). This chapter reviews the literature on the partial or complete loss of multiple pregnancies between the embryonic period and the time of fetal viability. Both the incidence and the potential etiologies of such losses are discussed.
