Pregnancy is associated with immune suppression, but recent research challenges this view, suggesting that the maternal immune system plays a critical role in supporting pregnancy. The immune system at the implantation site is not suppressed but actively functions to protect the pregnancy. Immune cells such as macrophages, natural killer (NK) cells, and dendritic cells (DCs) are present in the decidua and are essential for implantation and placental development. The presence of these immune cells is not a response to the fetus but is necessary for its survival. The immune system is not suppressed during pregnancy but is modulated to support the unique needs of the pregnancy. The fetal-maternal immune interaction is complex and differs from organ transplantation. The placenta plays a key role in shaping the immune environment, and trophoblast cells can influence immune cell differentiation and function. The immune response during pregnancy varies across stages, with the first trimester being proinflammatory, the second trimester anti-inflammatory, and the third trimester proinflammatory again. Inflammation is essential for implantation, placental development, and parturition. Immune cells at the implantation site are attracted by signals from the trophoblast and help in the process of implantation. The immune system is not suppressed but is carefully regulated to support the pregnancy. The role of immune cells in pregnancy is complex and involves multiple stages of interaction, including recruitment, education, and response. The immune system is essential for protecting the mother and fetus, and understanding its role is crucial for treating pregnancy complications and protecting pregnant women during pandemics.Pregnancy is associated with immune suppression, but recent research challenges this view, suggesting that the maternal immune system plays a critical role in supporting pregnancy. The immune system at the implantation site is not suppressed but actively functions to protect the pregnancy. Immune cells such as macrophages, natural killer (NK) cells, and dendritic cells (DCs) are present in the decidua and are essential for implantation and placental development. The presence of these immune cells is not a response to the fetus but is necessary for its survival. The immune system is not suppressed during pregnancy but is modulated to support the unique needs of the pregnancy. The fetal-maternal immune interaction is complex and differs from organ transplantation. The placenta plays a key role in shaping the immune environment, and trophoblast cells can influence immune cell differentiation and function. The immune response during pregnancy varies across stages, with the first trimester being proinflammatory, the second trimester anti-inflammatory, and the third trimester proinflammatory again. Inflammation is essential for implantation, placental development, and parturition. Immune cells at the implantation site are attracted by signals from the trophoblast and help in the process of implantation. The immune system is not suppressed but is carefully regulated to support the pregnancy. The role of immune cells in pregnancy is complex and involves multiple stages of interaction, including recruitment, education, and response. The immune system is essential for protecting the mother and fetus, and understanding its role is crucial for treating pregnancy complications and protecting pregnant women during pandemics.