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The presence of two fetuses of different ages, not twins, in the uterus, due to the impregnation of two ova liberated at successive periods of ovulation; an obsolete concept.
Formation or development of a second fetus when one is already present in the uterus, occurring normally in certain vertebrate species.
Etymology: L, super + fetus, pregnancy
the fertilization of a second ovum after the onset of pregnancy, resulting in the simultaneous development of two fetuses of different degrees of maturity within the uterus. Also called superimpregnation.
superfetationObstetrics Fertilization and subsequent development of a 2nd ovum after the 1st has already implanted in the uterus; superfetation provides the theoretic explanation for the difference in times of delivery of fraternal 'twins'. Cf Superfecundation.
superfetationThe rare occurrence of two or more fetuses of different ages in a womb that are the result of fertilizations occurring in different menstrual cycles.
the fertilization and subsequent development of an ovum when a fetus is already present in the uterus, a result of fertilization of ova during different ovulatory cycles and yielding fetuses of different ages.