Ay, brown discharge sa second trimester can be normal talaga, especially if wala kang iba pang symptoms like cramping or bleeding, pero better check with your OB para sure lang kasi everyone's pregnancy is different, a few of us mums had similar concerns and the doctor just monitored it, nothing serious naman. Make sure lang na hydrated ka always at kung may mas maraming bleeding or cramping suddenly, go to your hospital na agad okay? Congratulations sa buntis!