Loosing friends to motherhood
I am wondering if I am the only one who seems to have lost friends once having kids. I am not talking about not having time, although that can factor in. But what I mean is it clearly seems as though friends actively distance themselves once babies are in the mix. I am sad and hurt over it, honestly.
I think it has to do with judgement. As in, some mommy friends are so sensative to who does what, how, when nonsense. Like I breastfeed, you don't, she makes her baby food, her baby doesn't sleep through the night, blah blah comparison and judgement. Either that or I really smell or something. I joke, but really I don't get it.
I don't understand all the judgement and comparison. I personally think observing and sharing different parenting approaches is cool, interesting and an opportunity for learning. I certainly don't think my way is best, or works for everyone.
Of course there might be other issues in play here, I just don't know. Jealousy, SAHM v. WM thing, whatever. I'm just whinny and hurt. I want to ask my friend WTF!?!?! Perhaps I will. Nicely of course, in a non-judgemental way 
Re: Loosing friends to motherhood
I've "lost" a few of my single, party animal friends. I don't really miss them though, ha.
I don't care at all about BF, FF, WM vs SAHM, co-sleeping, whatever. My mommy friends do a variety of different things, and whatever works for them, is great!
I've distanced myself from a few "mommy friends" because I don't like the way they parent. I think the way you parent is a reflection on you as a person. I don't like screaming, crying, out of control kids... so if you come to a playdate at my house and your kid is out of control... you probably won't be invited back.
Also, I don't like to hang out with girls that just complain about their husbands and kids 24/7. That's not "fun" for me. Several of my friends would always compain about their deadbeat husbands, and it was annoying for me. I hardly see them anymore.
But for me at least, I've found that I really have to put in a LOT of effort to keep my friendships going. I do a monthly book club with my close friends, so that's an easy way for us to bond without babies around. I also plan a lot of playdates so I can see my girlfriends on a regular basis. I am the "planner" in my group of friends. If I don't plan a girls weekend, it's not going to happen. So for me, I make sure to plan things a lot!
In your instance, I would talk to your friend and find out if she's upset about something, or what's the deal. If you miss her, tell her that!
I was actually excluded a lot because I was not a mom before--I have had friends whom I introduced, and they ended up getting together behind my back since their kids were close in age and they were doing some activities together w/ the kids and "forgot" to call me. So I have distanced myself from both of them.
I am just done w/ friends like that, married or not, kids or not, if you're a crummy friend--you will be a crummy friend no matter what.