The paper outlines the modern day views of the transplacental transmission of IgG antibodies from mother to fetus as an important factor to protect of a baby from infections in the first months of life. It describes the impact of abnormal pregnancy and infectious diseases on the transplacental transmission of IgG antibodies. Particular emphasis is placed on the processes of vasculogenesis and angiogenesis underlying the development and function of the placenta at all stages of pregnancy. Emphasis is laid on the importance of further study of the factors and mechanisms influencing the transplacental transmission of IgG antibodies from mother to fetus for optimizing the preventive and therapeutic measures to improve the status of a fetus, a neonate, and a baby of the first months of life.