Association between maternal-fetal genetic histocompatibility and maternal undernutrition in mice: influence on intrauterine growth.

OBJECTIVE The purpose of this study was to evaluate the effects of maternal-fetal genetic histocompatibility and the association of that condition with maternal undernutrition regarding fetal growth and litter size. STUDY DESIGN Fetuses that were either syngeneic or allogeneic with the mothers were bred, using mice of well-defined syngeneic strains (A/J and Balb/c). Pregnant mice were fed using either unrestricted normal diet with 22% protein, consumed ad libitum, or a diet containing 14% protein, with intake restricted to 70% of that consumed by the unrestricted group. At the end of gestation, the number of fetoplacental units and fetal losses, the fetal and placental weight, and the weights of fetal brain and liver were recorded. RESULTS Fetuses from undernourished mothers showed a reduction in body, placental, and brain weight (P < 0.01); the association of undernourishment with maternal-fetal genetic compatibility resulted in a greater impairment of fetal growth (P < 0.01). A reduction in the number of viable fetuses per female in the dietary-restricted groups was observed. (P < 0.01). Although the concurrence of maternal-fetal genetic compatibility resulted in a trend towards a greater reduction in the number of viable fetuses as well as in a higher rate of fetal loss, these differences did not reach statistical significance. CONCLUSIONS In mice, the occurrence of maternal-fetal genetic histocompatibility alone did not change fetal growth; maternal undernutrition during pregnancy resulted in growth stunting of progenies with reduction of litter size; and the association of these 2 factors produced greater reduction of fetal weight.