This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Screening test used in first trimester for aneuploidy - \nSelect and explain. \nA. PAPP-A &estradiol, B. PAPP-A & AFP, C. PAPP-A &beta HCG, D. Beta HCG & inhibin', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is'c'i.e., PAPP-A &beta HCG1st trimester aneuploidy screening:Human chorionic gonadotropin (either intact or free (b-hCG).Pregnancy-associated plasma protein A (PAPP-A).Fetal Down syndrome in 1st trimester:Higher serum free beta-hCG level.Lower PAPP-A levels.Trisomy 18 & 13:Lowered levels of both HCG PAPPP-A.2nd trimester analytes:Serum integrated screening.Accuracy of aneuploidy detection:Greater on combination with,Sonographic NT measurement.", 'role': 'assistant'}]