In unconventional reservoirs, pressure changes observed in offset monitor wells during stimulation of a nearby treatment well can be used to characterize hydraulic fractures. However, current pressure interference models assume planar fractures and ignore the presence of pre-existing natural fractures. In this study we show that to accurately model pressure interference between fractured wells during stimulation, modeling complex fracture growth is important. We model dynamic fracture propagation from the treatment well and analyze pressure changes at an offset monitor well. Pressure changes in the monitor well are observed due to the stress shadow of a nearby propagating hydraulic fracture. Complex fracture growth can take the form of monitor well fracture propagation, fracture turning and natural fracture intersection.  These effects cannot be captured by traditional simulators assuming planar fractures. Our fracturing simulator captures the pressure interference between fractured wells while modeling such complex fracture growth. By capturing such fracture interactions (fracture turning, intersection with natural fractures) and their impact on pressure changes observed in the offset monitor well, our model provides a much more realistic representation of the physics of the problem.