My wife is pregnant and has placenta previa and is 34 weeks is now experiencing upper uterine cramping i want to take her to the doctor should i?

Yes: Placenta praevia, which means the placenta overlies the lower segment and/or cervix(opening of the uterus) can bleed, begin to separate from the uterine wall or pose threats to maintaining the pregnancy and proper blood flow to the fetus. Have your wife evaluated as soon as possible. Taking her to her OB doctor or the er is an excellent plan.