Vulnerability of placental antibody transfer and fetal complement synthesis to disturbance of the pregnant monkey.

Maternal and fetal/infant antibody levels were assessed across pregnancy and at birth to evaluate the prenatal transmission of IgG in the rhesus monkey. Although some antibody was evident in the fetus by midpregnancy, the marked increase in IgG occurred primarily during the last two weeks of pregnancy. This delay until the end of pregnancy would result in low antibody titers in premature infants. In contrast, when gestation length was normal, the placental transfer of IgG was resistant to both dexamethasone treatment and a prolonged period of stress during pregnancy. This resiliency occurred despite an effect of prenatal stress on other aspects of infant development, including physical growth and the fetal synthesis of complement proteins.