I've been taking valproic acid since childhood but have switched meds since. How will this affect pregnancy?

Valproic acid aka Epilim is used for the treatment of epilepsy. I am nearly 25 and have been taking it since i was 18months old. I have since switched to lamotrigine aka Lamictal and have been taking that for about 5 months. I understand the effects that Epilim can have if taken during pregnancy, and the lamicatal is considered somewhat safer. I want to know if I have been taking eplim for so long will it still have effects on the pregnancy even though I am no longer on it.
I am looking to fall pregnant soon and would like as much information as possible first.

Thanks