Does "expecting" mean "pregnant" exactly?

It’s a euphemism. From the etymonline entry for "pregnant":

The word tended to be avoided in polite conversation until c. 1950; modern euphemisms include anticipating, enceinte, expecting, in a family way, in a delicate (or interesting) condition. Old English terms included mid-bearne, literally "with child;" bearn-eaca, literally "child-adding" or "child-increasing;" and geacnod "increased." Among c. 1800 slang terms for "pregnant" was poisoned (in reference to the swelling).

The use of it always reminds me of a Lady Whiteadder (Blackadder's aunt) quote source

Aunt: [stands up] Don’t call me 'Aunty'!!! [slaps him twice] `Aunt’ is a relative, and relatives are evidence of sex, and sex is hardly a fitting subject for the dinner table. [sits]

It is a means of saying a baby is present but concealing the act of conception (because sex is "hardly a fitting subject" in polite company). Personally, I know where babies come from, so I’d take no issue with just saying "pregnant", but the contents of the news story you reference is already quite scandalous, so maybe the writer is simply attempting to tone it down for the more conservative amongst us.