Why do old friends, ociates ignore/isolate you during pregnancy?

I know the obvious reason, would be they weren't true friends. But I find it frustrating that, 9 months ago (yes, I am 9 months preggers currently) some of these same guys whom I had platonic friendships with or even business relationships were very active "friends" in my life. Calling, emailing, inviting me out, etc...and since finding out I was expecting---they have not shown any interest/support and are even ignoring me as in, if I email them/call, etc. I'm not married, and it's sorta obvious that the father is not in the picture. And NOOOO---I'm not looking to be dating or starting relationships with them or hoping they take a daddy role---but just having some male encouragement from guys whom I thought were my "friends" would have been encouraging during this time. And I mean, almost ALL my male friends---from the gay ones, to the ones I have had ual relationships in the past with, to ones who were real confidants. It makes me feel, that AFTER I have my son---I will no longer acknowledge them...and to add insult to injury---some of these guys who are acting uninterested in my pregnancy---are single dads too...so I almost feel like it's a double-standard. Like guys can go off and have children and be single, yet if a woman becomes pregnant and isn't married---she's damaged goods....Advice for how to rise above this...