Products of conception from 19 women immunized against rubella shortly before or during pregnancy were studied. Ten pregnancies went to term, and nine ended in abortion (eight induced). Vaccine-like rubella virus was recovered from the eye of one aborted fetus, the only instance in which fetal infection was demonstrated. Lenticular abnormalities typical of congenital rubella were observed in the other fetal eye, and particles resembling rubella virus were seen on electron microscopy. The seronegative mother had been immunized seven weeks before conception. The serologic status at the time of immunization of only one other woman is known and she was immune. The recovery of vaccine-like rubella virus from a fetus with histologic evidence of a cataract suggests that attenuated rubella virus may be teratogenic when given to susceptible women early in pregnancy or shortly before conception.
Fleet WF, Benz EW, Karzon DT, Lefkowitz LB, Herrmann KL. Fetal Consequences of Maternal Rubella Immunization. JAMA. 1974;227(6):621-627. doi:10.1001/jama.1974.03230190013003