My husband and i decided to start trying to concieve when i run out of birth control in 2 months. when should i start prenatals?

Now: You should start prenatals when you are trying to concieve.

Now... but: The cited average wait for a desired conception is 6 months with a wide range from weeks to a year. Beyond a year a review of fertility issues becomes valid. Be patient, things should go well & taking prenatal vitamins will help prepare your system for when it happens.