ADDENDUM AFTER CLARIFICATION:
I don't think this is a reduced relative clause. I don't think it's a relative clause at all. You've emphasized your example in a way that sets "women to sleep" apart as a unit, but it makes more sense to break it up like this:
She wanted to highlight pressure (on women) (to sleep with men).
Both "on women" and "to sleep with men" are preposition phrases that describe "pressure." Remove either one, or both, and you will still have a complete and accurate sentence.
Your two statements do not have identical meanings. The first sentence only says that women are pressured to sleep with men to enhance their careers. The emphasis is on the pressure, with no claims as to how the women respond to that pressure. Will sleeping with powerful men actually enhance their careers? We don't know, and it's not relevant to the meaning of the sentence.
The second sentence says that the women must sleep with men to enhance their careers "Must" makes the statement extremely firm: either women sleep with powerful men and enhance their careers, or they do not sleep with powerful men and do not enhance their careers. (Or, alternately, they have no choice but to both sleep with powerful men and enhance their careers). In this case, the pressure on the women involved is irrelevant because it doesn't change their options.