Placenta Previa & Uterine Blood Flow Simulator

Placenta previa is defined entirely by geometry: how close the placental edge sits to the internal cervical os. This simulator builds a 3D uterus with an adjustable placenta and cervical canal, lets you slide the placental edge from fully overlapping the os to a normal fundal position, and stretches the lower uterine segment the way late pregnancy and contractions do. A simplified Poiseuille flow model drives spiral-artery perfusion into the intervillous space, while a shear-stress model at the placental margin — proportional to segment stretch, contraction intensity, and how much of the os is still covered — determines when low-pressure venous bleeding begins, reproducing the classic "painless third-trimester bleeding" mechanism taught in obstetrics.