In 1961 you couldn't just fly anywhere at the drop of a hat. You had to be immunized to travel overseas so you could come back. I doubt seriously a prego that far along could be immunized.
Zippo would have been born a Kenyan so they probably wouldn't let him into the country without his shots, and he would have been too young to get shots.
Not to mention the time it would take to go to and from Kenya.
In 1961 I'm not even sure they would let a newborn that young on a plan.