We describe a method to obtain a 3D representation of objects given by a series of parallel cross-sections. We define a contour-to-contour connection based on geometric closeness and show a practical way to calculate an approximation using the Delaunay trinagulation. The performance of our method is shown on several medical examples. We further evaluate the precision of 3D models reconstructed from synthetic data and compare it to the marching cube reconstruction. In the third part, we use the 3D model of a pelvis and a fetal head for simulating a delivery. We calculate the forces applying on the head and define a measure of adequateness. This measure may be interesting for the decision of making a cesarean section.