Vanishing twin in the context of "Early pregnancy loss"

Early pregnancy loss is a medical term that when referring to humans can variously be used to mean:

• Death of an embryo or fetus during the first trimester. This can happen by implantation failure, miscarriage, embryo resorption, early fetal resorption or vanishing twin syndrome.
• Death of an embryo or fetus before 20 weeks gestation, as in all pregnancy loss before it becomes considered stillbirth.