Interactions between chronic murine Trypanosoma cruzi infection and pregnancy: fetal growth retardation.

Fetal growth, reproductive capacity, and parasitemia were studied in three groups of BALB/c mice: pregnant and chronically infected with Trypanosoma cruzi, non-pregnant but similarly infected, and pregnant but noninfected. The pregnant mice were killed on day 17 of pregnancy. Comparisons of the two pregnant groups showed significant differences in fetal weights and x18 magnified ossification lengths of radius and cubitus, whereas placental weights were not modified. The results indicate that intrauterine growth retardation occurs during chronic murine T. cruzi infection. No difference was noted between the reproductive capacities of the two pregnant groups. Parasitemias were similar in infected pregnant and control groups. Mice of all groups survived infection until killing. Pregnancy, therefore, does not influence chronic murine T. cruzi infection. Parasites were never found in fetal blood, indicating a very low, if any, frequency of transplacental transmission of parasite during the chronic phase of infection.