Multiple pregnancy in human is not a physiological event because the anatomy of the human uterus is designed to harbour only one fetus at a time.
Placenta of biamnial biplacental twins:
Biamnial bichorial placenta, twins, Macro, autopsy (73279)
Another case:
Biamnial bichorial placenta, twins, Macro, autopsy (73280)
Twins and bichorial biamnial placenta:
Placenta, twins, Macro, autopsy (73974)
Bichorial biamnial placenta:
Placenta, bichoriadal biamnial twins, Macro, autopsy (73996)
Fetal death in multiple pregnancy:
Suprisingly many pregnancies begin as multiple, but one fetus usually dies sooner than multiple gravidity is recognized (before 10th w.g):
Fetus compressus, two placentas with minimal fusion:
Twins, fetus papyraceus, Macro, autopsy (72393)
Twins, fetus papyraceus, Macro, autopsy (72394)
Twins, fetus papyraceus, Macro, autopsy (72395)
Vanishing twin:
Vanishing twin, Macro, autopsy (73072)
Vanishing twin, Macro, autopsy (73073)
Vanishing twin, Macro, autopsy (73074)
Triplets, fetoreduction:
Triplets, fetal reduction, Macro, autopsy (73342)
Triplets, fetal reduction, Macro, autopsy (73343)
Triplets, fetal reduction, Macro, autopsy (73344)