actually up till now i have not worn any maternity pants.. I'm in my 3rd tri btw. I just wear pants that are stretchy and 2 sizes up.
I was still wearing my pre-preggy jeans in my 1st tri.. and no1 knew i was preggy until i was in my 2nd tri. hehe.
Of course, i wouldn't recommend wearing pants that are too tight, but do dress what you feel comfortable in. =)