Harjulehto T, Aro T, Hovi T, Saxén L
Department of Pathology, University of Helsinki, Finland.
Lancet. 1989 Apr 8;1(8641):771-2. doi: 10.1016/s0140-6736(89)92584-1.
In February, 1985, mass vaccination with live oral poliovirus vaccine (OPV) was started during a poliomyelitis outbreak in Finland. Pregnant women were advised to take the vaccination. Judged as the rate of reported malformations, OPV during early pregnancy had no harmful effects on fetal development.