How can i tell my parents that i'm pregnant?

I am 18 years. old and have been with my b/f for almost 2 years. I just found out that I'm 4 months pregnant and have still had my courses throughout the pregnancy. My parents know that I've been having my period, so how do I tell them that I'm...

pregnant without them jumping to conclusions, especially since they have been known to be alittle abusive? Should I have the baby's father with me while I tell them? Would that make it seem alittle bit better or more worse?

well you are 18 now... Maybe call them and tell them that they are going to have alittle grandchild...now, just tell them that your growing up and you want to make a family now.
But if you do go and meet them in person make sure you do have your boyfriend there with you...incase you need to leave fast or something.

Try writing them a letter, leave is somewhere they can find it, and then leave the house. They'll find it and come and talk to you. You're 18, and considered an adult.\, so be mature when they confront you, they will think you're ready for a family if you ant one.

Since your parents are known to be abusive (maybe verbal or abusive, you didn't say) you may to tell over the phone, which is good for your health and the baby as well. Tell them that you're going to have a baby (if you are certain that you are keeping it) or tell them that you're pregnant (if you're undecided as to whether or not you are keeping it or giving it up for adoption etc.)
Parents may not always be supportive while your pregnant but once you have the baby, some parents do come back around.
I hope that your parents will be by you every step of the way as well as your baby's father!
As for bringing your boyfriend along with you while you break the news to them in person I wouldn't recommend it, I say let him stay close by just in case he's needed.
Or you could have him there with you for moral support I guess (just hope your parents don't turn against him)...
Best of luck,

yes, please bring your boyfrined.. so that maybe he can taka punch for you? BUT. anyhow.. good luck, try to seem calm about it, dont be like OH, OH! IM PREGNANT WHAT NOW H?^$!@!? you know? anyway.. good luck.