This is an unknown because there have not been any studies done. That aside, it is known that in the fetus, there is a state of rapid replication of cells which makes them more physiologically sensitive to external stimuli. It is not just drugs that can cause aberrant development in the fetus.
For this reason, and others, Dr. Clark warned not to use the zapper on any woman who was expecting or might become pregnant. I am quite certain that she would not be alone in stating this.