Abortion.

"It's a parasite."

Is it though? 

Here are the three characteristics of a parasite. 

- invades the host's body

- is a different species

- derives nutrients from the host

- is followed by immune system reaction due to being foreign

You need all four of those to be parasite.

Now, let's look at a fetus.

- It doesn't invade the mother's body, it is created within. 

- It is the same species as the mother; Homo Sapiens.

- The fetus and mother share nutrients. The fetus also "exchanges" just like the mother does.

- No immune reaction (infection, ect). The body knows not to attack fetuses even though they're "foreign" (different DNA that doesn't match with mother's).

So you can call it a parasite, yet, it is scientifically incorrect to do so.