Genetic testing!

Hello ladies.! I was wondering how a genetic test was done?? This is my 3rd pregnancy (second pregnancy ended in a miscarriage). In my first pregnancy I don’t remember how genetic testing was done I’m not sure if it was by blood work.

I’m 14w & 4d. My appointment is on Monday @9am (I’ll be 15 weeks) i was curious on how long is the app.? What happens at the app & how is the test done.? I been reading that they can do a needle in the belly & I’m freaking out.! Can you share your experiences please❤️