The amount of amniotic fluid at 12 weeks of pregnancy is:

Amniotic fluid measures about 50 ml at 12 weeks, 400 ml at 20 weeks and reaches its peak of 1 litre at 36-38 weeks. Thereafter the amount diminishes, till at term it measures about 600-800 ml. As the pregnancy continues post term, fuher reduction occurs to the extent of about 200 ml at 43 weeks. In general, the volume increases by 10 mL per week at 8 weeks and increases up to 60 mL per week at 21 weeks, then declines gradually back to a steady state by 33 weeks. Ref: Textbook of Obstetrics by D C Dutta, 6th edition, Page 37.