<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: Which is the MOST appropriate gestational age for performing amniocentesis?
Options:
A. 10-12 weeks
B. 12-16 weeks
C. 20-25 weeks
D. 25-30 weeks
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is B: 12-16 weeks. Explanation: Amniocentesis is ideally performed between 14-16weeks of gestation. Early amniocentesis can be carried out at 12-14 weeks under ultrasonographic guidance. The fetal cells so obtained are subjected for cytogenetic analysis. Fetal fibroblasts and fluid for biochemistry are used for study. Chorionic villus sampling : is carried out transcervically between 10 - 12 weeks and transabdominally from 10 weeks to term. Trophoblast cells are used for study. Cordocentesis: Is done between 18-20 weeks of gestation. Fetal WBCs are used for study. Ref: Textbook of Obstetrics By DC Dutta 6th edn page 107-8.<|im_end|>
