Certain infections in the pregnant woman may be accompanied by deleterious effects on the fetus, regardless of the presence of fetal infection. Severe maternal infection can lead to fetal death in utero or to premature labor; less severe infections in the mother seem to be involved in the pathogenesis of fetal growth retardation.
The Figure is a set-theory diagram to illustrate a basic mechanistic concept, that various normal nutritional, biochemical, metabolic, or endocrine processes in the mother may be altered during states of infection or pregnancy. Individual maternal processes (illustrated by capital letters in the several sets) may be enhanced or suppressed as a typical physiologic response to pregnancy (lower middle set) or may remain unaltered. Infection (top middle set) initiates many specific responses in the host. In a pregnant woman, individual maternal processes may remain unchanged or may exhibit synergistic, antagonistic, or noncorrelating responses to the combination of both
Beisel WR. Synergistic Effects of Maternal Malnutrition and Infection on the InfantRecommendations for Prospective Studies in Man. Am J Dis Child. 1975;129(5):571–574. doi:10.1001/archpedi.1975.02120420027009