My friend Laura Crossett suggested terminology to the nice folks at LC. She let me share her suggestion here, cuz she's CC like that.
I recommend changing the terminology for http://id.loc.gov/authorities/subjects/sh85106293 from "Pregnancy, Unwanted" to:
The latter is used by the CDC in describing pregnancies that are "mistimed, unplanned, or unwanted at the time of conception,*" which I suppose is a broader term than simply "unwanted pregnancy"--but that would mean it could be applied to a greater range of situations, which might prove useful, as there is currently no subject heading appropriate for a woman who finds herself pregnant when she was not anticipating such an event. Not all unintended or unplanned pregnancies are unwanted, or end up being that way. I had one myself and wrote a book about it, in fact.
An unplanned or unintended pregnancy a common occurrence: almost half the pregnancies in the United States fit that description. An unwanted pregnancy suggests a moral judgment, something I would hope the LoC tries to avoid.
Thank you very much for your time and consideration,