Misti,
I've had several midwives who didn't recommend RR Tea in the first trimester, especially if you don't normally drink it. My current midwife suggests using it from the very beginning.
Personally, I'm usually (shamefully) out of the regular habit of drinking it when I get pregnant again, so I generally avoid it during the first 12 weeks, and slowly build back up to drinking up to 1-2 quarts per day before delivery.
I like to mix RR, Oat Straw, Nettles, and Alfalfa in my pregnancy tea, and add in a bit of mint for flavor. Before I got used to the taste, I also had honey as well, but I'm so used to the flavor now that the honey is almost too sweet. I also like to chug the tea after birth to replenish those vitamins and minerals as well as promoting healing.
Congratulations!!