1) Conceive 
to conceive during pregnancy
• (v. i.) To conceive after a prior conception, but before the birth of the offspring.
Su`per·fe'tate intransitive verb [ Latin superfetare ; super above, over + fetare to bring forth.] To conceive after a prior conception, but before the birth of the offspring. « The female . . . is said to superfetate .» Grew. 
[v] - conceive when a fetus is already present in the uterus