My wife (15 weeks pregnant)has a sharp cervix pain with brown discharge. what could be the cause? is it normal at this stage of pregnancy?

Bleeding in preg: The brown discharge is blood that has been sitting in the vaginal vault for a few days. It may have been blood from the cervix, post coital bleeding or even from the uterus or placenta. It can be a sign of infection too. It is probably nothing but it is worth seeing your OB for an exam, possibly cultures and an ultrasound to be sure it isn't a sign of placenta problems or cervical incompetance.