I Did My Scan At Start Of 7 Month Pregnancy.AFI

I did my scan at start of 7 month pregnancy.AFI was slightly reduced upto 14.7 cm.after that I was under observation,i did my next scan after two weeks AFI was again reduced to 11.5cm .my umbilical artery Doppler was normal..I took a lot of liquids within these two weeks bt still it's gradually decreasing...