This paper analyzes the influence of pregnancy stage and fetus position on the whole-body and brain exposure of the fetus to radiofrequency electromagnetic fields. Our analysis is performed using semi-homogeneous pregnant woman models between 8 and 32 weeks of amenorrhea. Analyzing the influence of the pregnancy stage on the environmental whole-body and local exposure of a fetus in vertical position, head down or head up, in the 2100 MHz frequency band, we concluded that, during the first pregnancy trimester, both whole-body and average brain exposures of the fetus decrease while advancing in the pregnancy due to the rapid gain of weight of the fetus during these first stages. From the beginning of the second trimester, the whole-body and the average brain exposures are quite stable because the weight gains are quasi proportional to the absorbed power increases. The behavior of the fetus whole-body and local exposures during pregnancy, for a fetus in vertical position with the head up was found of similar level, compared to the position with the head down, but slightly higher especially in the brain.