<prompt> A 32-year-old woman is confirmed as being 6 weeks pregnant. She feels well, and has no past medical history. This is her second pregnancy; the first pregnancy was uncomplicated and she delivered at term, but the baby was anemic due to beta-thalassemia. She is now worried that the current pregnancy may also be affected. Which of the following methods is most likely to establish an accurate prenatal diagnosis?fetal ultrasound at 12 weekscord blood electrophoresischorionic villus samplingbuccal mucosal cytology of both parents  <response>: Chorionic villus sampling in the first trimester with deoxyribonucleic acid DNA-based diagnosis has a high degree of accuracy. Cord blood electrophoresis is suitable for screening high-risk infants at birth. 