Does Vyvanse Prevent Implantation?

Hi, I am 25 years old, 61 inches, and 100 pounds and have been taking ADHD medication for 10 years now. I was previously on Adderall now I currently take Vyvanse. My husband and I are trying to conceive. I go to a hollistic doctor and she says that the baby does not get anything from the mother until approximately 8 weeks but to try and decrease mg's until then. I am still nervous and would like to know if Vyvanse is known to prevent implantation or if it would hurt the baby until the 8 week mark. Thankyou