excess folic acid during pregnancy is very dangerous????

Moms, I just found out that excess folic acid during pregnancy is very dangerous for the baby. They say it can cause autism???? This is my first time being pregnant and i am really scared of everything that could potentially harm my baby. My doctor prescribed me folic acid vitamins... I’m really scared, it's such a gamble. If I don't take it, I’m afraid of deficiency, and if I take it every day, I’m afraid of excess. But what are the signs of excess folic acid, moms? Does anyone know? I hope we all stay healthy. #seriousquestion