Final answer:
An incomplete abortion is when some, but not all, products of conception have been expelled from the uterus during pregnancy termination.
Step-by-step explanation:
Abortions that have passed some, but not all, of the products of conception are known as incomplete abortions. In these cases, the pregnancy has ended with the expulsion of some of the fetal tissue or placenta from the uterus, however, some products of conception still remain inside. This contrasts with a complete abortion, where all pregnancy tissue has been passed, a threatened abortion, which may result in pregnancy loss but has not yet done so, a missed abortion, where the fetus has died but is still retained in the uterus, and recurrent abortion, which refers to multiple consecutive miscarriages.