Does anyone know what birth defects methadone cause?

I am currently at 5Mg's and am getting very conflicting information. I will soon be enrolling in a methadone clinic but I want information before I start so I am informed, I don't want them to keep me on it just to make money. I am currently 3 months pregnant.

: http://alcoholdrugstreatment.info/does-anyone-know-what-birth-defects-methadone-cause