PAPP-A plays many important roles in the development of the embryo, especially helping the growth and development of the placenta, controlling the development of the fetus due to its function of regulating the absorption of amino acids and glucose by young cells (through the release of IGF factor), in addition, PAPP-A helps protect the fetus from the mother's immune system. So is a low PAPP-A concentration in the Double test a cause for concern?