Can I understand your family's disappointment in missing their daughter's wedding? Absolutely. However, you're married now. If they are still saying nasty things, then I don't see why you would share your pregnancy news with them. If they aren't supportive in general, why give them the opportunity to be condescending and hurtful?
If you are determined to tell them, wait until your first trimester is over. Once you tell, you can't untell. God forbid something happens, and then you get to hear even more negativity from your mom.
I think you should tell them just as you would if you weren't afraid of them being upset, with one big exception -- drop some hints, first. Tell mom you have exciting news you'd like to share with her, but not until hubby's there/skype/in-person. She'll probably guess what the news is (even if it's her worst fear), and be able to compose herself in order to react appropriately.
Of course, you know her best. So, you'd know if this is what you can expect from her, or not.
In my observation over the years, Moms are usually so excited about grandchildren that they're willing to overlook everything else that they thought was horrible about the chosen significant other before.
Can I offer a reply here?
MH and I got married without telling anyone and hurt a lot of feelings as well (those bridges have been mended). We took my mom and only my mom out to dinner because I didn't want to tell my dad yet I wanted to have her as a buffer, while at dinner waiting for our appetizers she says, "ok what's up you two look like the cat who caught the cannery" some silence followed and then she says "and if you tell me your pregnant I'm gonna shoot you" (no idea where that came from she isn't a violent type it was pretty out of character for her, this was only 4 months after we had gotten married) MH replies "well what kind of gun do you want I'll go get it"
We were all able to make light of the situation and how awkward my mom's response was and they all eventually showed how happy there were etc. However that pg ended in a MMC I am happy that I told them because they have been a source of support for me through our challenges TTC but at the same time not everyone receives that kind of support when the worst happens.
I hope you have a healthy pg and never have to experience that hurt. As for how to tell there's a couple good suggestions above or you can just go with the flow and see what happens. I believe our pg helped to lighten the mood in general and got everyone talking and started to mend the relationships.