This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Prenatal Diagnosis, Subject name: Gynaecology & Obstetrics
[{'content': "Increased nuchal translucency at 14 weeks of gestation is seen in: \nSelect and explain. \nA. Turner's syndrome, B. Down's syndrome, C. Esophageal atresia, D. Klinefelter's syndrome", 'role': 'user'}, {'content': "Answer: B \nExplanation: First-trimester screening at 11 to 14 weeks' gestation, using the fetal nuchal translucency measurement together with serum analytes like PAPP-A and HCG levels , has achieved Down syndrome detection rates comparable to those for second-trimester screening in women younger than 35 years. It is measured in the sagittal plane between 11 and 14 weeks, when the crown-rump length measures between 38 and 84 mm. Increased fetal nuchal thickness is a strong marker for chromosomal anomalies in the first trimester. Increased fetal nuchal translucency i.e. > 3 mm on ultrasound is suggestive of trisomies", 'role': 'assistant'}]