superfetation

英 [sjuːpəfiː'teɪʃən] 美 [ˌsjuːpəfiː'teɪʃən]

• [生]异期复孕, 重孕

英英释义

Noun:

1. fertilization of a second ovum after a pregnancy has begun; results in two fetuses of different ages in the uterus at the same time;

   "superfetation is normal in some animal species"