Hi C.,
Is this the only time that your friends has behaved this way? Since she has become pregnant? If it is then maybe it is just hormones and it will pass. How long have you two been friends?
Maybe you are on to something when you talk about maybe a little jealousy. Maybe she is feeling because you work and also have a family to take care of as well as other daily things that must be done, she see's your life as happy, complete I don't know. Even though she is pregnant maybe she isn't feeling as fulfilled as she would like. Sometimes when there are things going on in a friends life they will take their hurt or anger out on someone close to them.
Maybe you could try to sit down with her and tell her how you are feeling without making it sound like an attack on her, maybe she will open up but if not then maybe what another respondant said is closer to the truth, sometimes people just out grow the friendship and is wasn't meant to last.
Either way I would talk to her because unless you mention it then you will never truely know and if your like me (and it sounds like you are) this will weigh heavy on your mind until you get it out. Are you two neighbors? That is even more reason to try and at least talk just because you live next to eachother.
It is very hard to find a good friend, I know I go through that alot. Good luck and let us know how it went.
L.