ultrasound

I have blood work being done this Friday/ STD screening/ cervical cancer screening. I will be just over ten weeks. I go back in arounf 13 weeks (October 7th) to find out if my child has any birth defects/down- syndrome. I will always love my child no matter what. I am just worried that if is something is wrong I will blame myself entirely. I didn't know I was pregnant for five weeks and I was smoking and drinking heavily. I know people have told me that people do not know they were pregnant for awhile and have had children be fine but I still can't help but worry. Does anyone know the odds of having a child with birth defects at 22 years of age? Is it just genetics?