The term expecting is often used as if it means "pregnant", as shown by Merriam-Webster (for the verb expect)
3 : to be pregnant : await the birth of one's child —used in progressive tenses she's expecting next month
and Oxford Dictionaries says
informal Be pregnant.
‘his wife was expecting again’
but logically you can only be expecting if you are knowingly pregnant and anticipating a successful conclusion.
There seem to be two issues here. One is how we should use terms that are metaphorical in origins in particular contexts where the original meaning seems to be the opposite of the derived meaning.
The other is whether we should go by the dictionary when we suspect the dictionary writers were not specific enough in their definition.
Note that this question was motivated by a news report that said that surgeons "discovered that [Ebony, who did not previously know she was pregnant] was expecting a baby [while she was in a coma], and I thought, "How could she be expecting a baby or anything else whilst in a coma?"