I'ts hard to say this time of year, how long you should wait. Couple of weeks is how long my wife and I waited, but that was in the summer months. You may want to wait until the first vaccinations are done considering the time of year. your child will carry the mothers immunities for the first coupe of months. (my wife and I have a 15 month old and another due in January, so this is all still fresh in my head)