Magical Abortion

Like in nature to the Convenient Miscarriage, a Magical Abortion is what happens when a female hero on a supernatural series becomes pregnant, but the writers—terrified of addressing the issue of actual abortion and dissatisfied by the idea of doing a simple miscarriage—find a way to get rid of the unwanted foetus that involves magic in some way, thus making it less controversial. It differs from the Convenient Miscarriage in that the pregnancy is directly and deliberately terminated, rather than naturally miscarried.

Almost always involves a Fetus Terrible plot, where mundane abortions logically wouldn't work anyway. Doesn't apply to the Face Full of Alien Wingwong, which doesn't really resemble a real life pregnancy at all.

Contrast Plot-Relevant Age-Up and Soap Opera Rapid Aging Syndrome, where the inconvenient infant is born and then matured to a more usable character.

Examples of Magical Abortion include:

Comic Books

A variant was used by Marvel Comics for the Scarlet Witch; she actually had her children (with a robot, and before you ask, we're not sure how that works either, but when they got inconvenient they were Ret Conned into being figments of her imagination mixed with the soul of a demon-lord. When you have Reality Warper powers that aren't under your complete control, it's not the most far-fetched thing that could happen. And then these "imaginary" children are now members of the Young Avengers. Sort of.
- All... those... poor... mutants...
The now-infamous One More Day storyline of the Spider-Man canon also included Mary Jane's pregnancy getting aborted as part of the big magic Retcon. For irony's sake, Joe Quesada didn't want Spidey and MJ getting divorced because it might be seen as objectionable... so instead, he whipped up a storyline where a superhero makes a Deal with the Devil and gets a free abortion in the process.

Film

Near the end of Constantine, John's love interest and girl sidekick Angela becomes mystically impregnated with the Antichrist, which is sent back to Hell through a personal appearance by Satan. In this case she wasn't so much literally pregnant as acting as sort of "flesh-gate" to hell.
An odd film example comes in a flashback scene at the beginning of Warlock II: The Armageddon. A nameless female that becomes mystically pregnant with the titular Warlock is shown having the full-term foetus exorcised out of her with mystical jewellery. No, seriously.
Night Watch starts with the hero getting a witch to magically abort his ex girlfriend's pregnancy so she would come back to him. He backs out of going through with it but it still comes back to bite him.

Literature

In the Dragonriders of Pern universe, the between used in teleporting is very cold, seeing as how it is absolute nothingness. Female dragonriders who go between too often or too long can end up infertile or sterile, and at least one dragonrider has deliberately used it to induce multiple abortions.
- In some books in the series 'taking a short dragon ride' is mentioned as a Pernese euphemism for abortion.
One character in Black Dogs uses the Kytha (a kind of physical magic) to abort a pregnancy by rape and purposefully sterilizes herself in the process. She knew that if she simply aborted the baby, the villain would just rape her again and again until she conceived and bore a living child.
In A Song of Ice and Fire exposure to dark magic in the womb kills Danaerys' unborn son, mutating and decaying him.

Live Action TV

Cordelia on Angel was pregnant twice over the course of the series, only the last of which resulted in an actual birth. Her first pregnancy in season one (Expecting) with demonic septuplets was terminated supernaturally by the death of their demon daddy, which destroyed the evil babies by proxy through a psychic connection.
- Apart from the two actual pregnancies (three if you count the demon eggs in her skull) Cordelia was also faced with numerous impregnation attempts. "And when we're finished here, can we go and find some world somewhere where an ugly demon doesn't want to impregnate me with his demon seed? I mean, is it me? Do I give off some kind of 'come-shuck-me' vibe? You'd tell me, right?"
- Subverted with Darla, who tried to find some way to get rid of her pregnancy, whether mundane or magical, but couldn't--fetus!Connor basically had a magical force field around him. Ironically the thing that came closest to killing him was his actual birth, since the same magic caused complications before Darla, who was vicariously able to love Connor since he had a soul, staked herself so that he could survive.
Phoebe on Charmed arguably had the most far-fetched use of this trope, when her Antichrist-like son was transferred out of her body into the uterus of another woman, The Seer, whom the Charmed sisters then killed. Pheobe doesn't seem particularly shaken up about it, which makes sense since when the baby controlled her she felt that it wasn't hers nor did it have a soul (which was true, since it was the Seer's own evil spawn) and it absolved her of all the crappy things she did while she was pregnant.
Arlene of True Blood tries to have one with the help of a witch in season 3, because the baby's father was a Serial Killer. It doesn't work.

Video Games

Silent Hill 3 features a magic abortion pill - just the the thing you need when you're about to give birth to an evil god. Unfortunately she's a little too far along...