Differentiation of the specialized epithelial cells of the placenta, termed cytotrophoblasts, is a
particularly important aspect of placental development during the first trimester of pregnancy.
During this process cytotrophoblast stem cells either fuse to form the syncytium or aggregate
to form cell columns that adhere to, then invade the uterus. We found that chorionic villi from
early gestation placentas of mothers who smoke showed a marked reduction in cell
columns, a defect that could not be corrected by placing them in culture. We used two …