I'm 33 yrs old ..want to get pregnant ..but so worried that i'd get a baby withdown's syndrome so what are tests at first trim.concerning this disease?

11-13 weeks in: The doctor uses ultrasound to measure a specific region on the back of a baby's neck.This is known as a nuchal translucency screening test.When abnormalities are present, more fluid than usual tends to collect in this tissue.Results of the ultrasound are paired with blood tests that measure levels of pregnancy-associated plasma protein-a (papp-a) and a hormone known as hcg.