Selective Reduction
Imagine it. A couple longs to have a child, but they can't. They go through the rigors of treatment and find they're good candidates for in vitro fertilization. So they lay out the ten grand (or more) for IVF, and the doc transfers five embies to the uterus. Amazingly four of them implant.
Uh oh. That's too many. So they choose to abort or (euphemism:) reduce the ones they don't want.
You can read about the practice in this Washington Post article.