These microscopic slides of mouse placentas and uterine tissue show the importance of the protein Gab3 for ensuring a healthy delivery. On the left, in normal, wild-type mice (WT) the brown-colored cells, the placental trophoblast, form an area called the junctional zone (JZ) and few cells enter vessels in the maternal decidua (DB). The uterine wall and the rest of the decidua (DB) are clear. This allows the placenta to detach properly during delivery. The middle image shows much deeper penetration when mice have a mutated form of Gab3. The image on the right shows even deeper penetration when mice completely lack Gab3. The last two conditions result in retained placenta, a high risk of severe bleeding and possible death for the mother. Detailed findings were posted online Aug. 2 in Science Immunology.