I took an MA in CW about 15 years ago, and have since taught at two universities, in addition to writing for a living.
It's not a magic bullet, no. But it does give you 1) Structure and deadlines. This is so so helpful, especially for those who have been writing inside their heads for ages, and need to get it down on paper. 2) Community. Being with like-minded, serious writers - some of whom you'll not get on with, but many you will, is invaluable. I still have close friends/colleagues from my course and we've all helped each other get on. 3) You will, at the end of the course, have something approaching a "body of work" that you can show an agent. It is highly unlikely that would happen without no.1, or you would have done it already.
I am highly dubious of online support groups, which are mainly made up of wannabe writers, rather than serious aspiring professionals (apologies to anyone who is the exception).
As far as the possible pregnancy goes I don't actually think it's an issue. I'm not unsympathetic, as I had fertility problems myself, and in fact was having treatment during my MA. You're not yet pregnant, and when you are you can deal with it. Bear in mind there will NEVER be an ideal time to do the MA - everyone I know who made a success of it had a million other things going on in their lives (dying parents, divorce, young children etc), and that's not entirely a bad thing. If you become a professional writer, the world is not going to stop, so the sooner you learn how to focus on your work amid life's chaos, the better.
You have absolutely nothing to lose by applying. Apply and get accepted before going through all these arguments. Good luck OP.