Hi, Vyvanse is not known to affect the fertility if consumed in moderation or for short course. It can cause serious side effects on the growing embryo when consumed during pregnancy. There can be fetal malformations if used during pregnancy. If the medication is stopped much before conception, then there is no need to be worried. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Raju A. T., General & Family Physician