Illustration of different positions of the fetus in the abdomen at 16 weeks. At the 16th week of pregnancy, the fetus has developed to a considerable extent. The position of the fetus in the abdomen at this time has a great impact on pregnant women and doctors. Below we will provide detailed illustrations of the different positions of the fetus in the abdomen at 16 weeks from four aspects. 1. The influence of fetal intrauterine position on development increases with the progression of pregnancy.