spontaneous miscarriages

When Do Trisomy Babies Miscarry? It is estimated that approximately 80% of Trisomy 21 pregnancies end in a miscarriage (pregnancy loss before 20 weeks of gestation) or intrauterine fetal demise (pregnancy loss after 20 weeks of gestation), while 20% may progress to term delivery. When do most trisomy miscarriages occur? Most pregnancies with a rare